Table Of Contents
half-duplex controlled-carrier
loopback local (T1 controller)
loopback remote (T1 controller)
service-module 56k clock source
service-module 56k data-coding
service-module 56k network-type
service-module 56k remote-loopback
service-module 56k switched-carrier
service-module t1 clock source
service-module t1 remote-alarm-enable
service-module t1 remote-loopback
Interface Commands
This chapter contains the commands used to configure interface features that are not protocol-specific. For hardware technical descriptions, and for information about installing the router or access server interfaces, refer to the hardware installation and maintenance publication for your particular product.
For interface configuration tasks and examples, refer to the chapter entitled "Configuring Interfaces" in the Configuration Fundamentals Configuration Guide.
For information about the Channel Interface Processor (CIP), see the chapter entitled "IBM Channel Attach Commands" chapter in the Bridging and IBM Networking Command Reference. The CIP is described in a separate chapter because of the interrelationship of host system configuration values and device configuration values.
Note
Some commands previously documented in this chapter have been replaced by new commands. Although they continue to perform their normal functions in the current release, support for these commands will cease in a future release.
access-list (standard)
Use the access-list global configuration command to establish MAC address access lists. Use the no form of this command to remove a single access list entry.
access-list access-list-number {permit | deny} address mask
no access-list access-list-numberSyntax Description
Default
No MAC address access lists are established.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Related Command
access-list (type-code)
access-list (type-code)
Use the access-list global configuration command to build type-code access lists. Use the no form of this command to remove a single access list entry.
access-list access-list-number {permit | deny} type-code wild-mask
no access-list access-list-numberSyntax Description
Default
No type-code access lists are built.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Type-code access lists can have an impact on system performance; therefore, keep the lists as short as possible and use wildcard bit masks whenever possible.
Access lists are evaluated according to the following algorithm:
•
•
If the length/type field is greater than 1500, the packet is treated as an LSAP packet unless the DSAP and SSAP fields are AAAA. If the latter is true, the packet is treated using type-code filtering.
If you have both Ethernet Type II and LSAP packets on your network, you should set up access lists for both.
Use the last item of an access list to specify a default action; for example, permit everything else or deny everything else. If nothing else in the access list matches, the default action is normally to deny access; that is, filter out all other type codes.
Related Commands
access-list (extended)
access-list (standard)async default ip address
The peer default ip address command replaces the async default ip address command. Refer to the description of the peer default ip address command for more information.
async default routing
To enable the router to pass routing updates to other routers over the AUX port configured as an asynchronous interface, use the async default routing interface configuration command.
async default routing
Syntax Description
This command has no keywords or arguments.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use the async default routing command to define the default behavior for router-to-router communication over connections to the AUX port configured as an asynchronous interface.
To require a remote user to manually configure routing over connections to the AUX port configured as an asynchronous interface, use the async dynamic routing command.
Example
The following example enables routing over asynchronous interface 0:
interface async 0async default routingRelated Command
async dynamic routing
async dynamic address
To specify an address on an asynchronous interface (rather than using the default address), use the async dynamic address interface configuration command. Use the no form of this command to disable dynamic addressing.
async dynamic address
no async dynamic addressSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example shows dynamic addressing assigned to an interface:
interface async 1async dynamic addressRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
ppp †
slipasync dynamic routing
To enable manually configured routing on an asynchronous interface, use the async dynamic routing interface configuration command. Use the no form of this command to disable routing protocols; static routing is still used.
async dynamic routing
no async dynamic routingSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example shows how to enable manually configured routing on asynchronous interface 1. The ip tcp header-compression passive command enables Van Jacobson TCP header compression and prevents transmission of compressed packets until a compressed packet arrives from the asynchronous link.
interface async 1 async dynamic routing async dynamic addressasync default ip address 1.1.1.2 ip tcp header-compression passiveA remote user who establishes a PPP or SLIP connection to this asynchronous interface can enable routing by using the /routing switch or the ppp/routing command.
However, if you want to establish routing by default on connections to an asynchronous interface, use the async default routing command when you configure the interface.
Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
async default routing
async dynamic address
ip tcp header-compression †async mode dedicated
To place a line into network mode using SLIP or PPP encapsulation, use the async mode dedicated interface configuration command. Use the no form of this command to return the line to interactive mode.
async mode dedicated
no async modeSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
With dedicated asynchronous mode, the interface will use either SLIP or PPP encapsulation, depending on which encapsulation method is configured for the interface. An EXEC prompt does not appear, and the line is not available for normal interactive use.
If you configure a line for dedicated mode, you will not be able to use async dynamic address, because there is no user prompt. You must configure either async default ip address and ip unnumbered or ip address.
Example
The following example assigns an Internet address to an asynchronous line and places the line into network mode. Setting the stop bits to 1 enhances performance.
interface async 1async default ip address 182.32.7.51async mode dedicatedencapsulation slipRelated Command
async mode interactive
async mode interactive
To enable the use of slip and ppp EXEC commands, use the async mode interactive line configuration command. Use the no form of this command to prevent users from enabling SLIP and PPP at the EXEC level.
async mode interactive
no async modeSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example enables the ppp and slip EXEC commands:
interface async 1async mode interactiveRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
async mode dedicated
ppp †
slip †auto-polarity
To enable automatic receiver polarity reversal on a hub port connected to an Ethernet interface of a Cisco 2505 or Cisco 2507, use the auto-polarity hub configuration command. To disable this feature, use the no form of this command.
auto-polarity
no auto-polaritySyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Hub configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
This command applies to a port on an Ethernet hub only.
Example
The following example enables automatic receiver polarity reversal on hub 0, ports 1 through 3:
hub ethernet 0 1 3auto-polarityRelated Command
hub
backup delay
To define how much time should elapse before a secondary line status changes after a primary line status has changed, use the backup delay interface configuration command. To return to the default, so that as soon as the primary fails, the secondary is immediately brought up without delay, use the no form of this command.
backup delay {enable-delay | never} {disable-delay | never}
no backup delay {enable-delay | never} {disable-delay | never}Syntax Description
Default
0 seconds
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When a primary line goes down, the Cisco IOS software delays the amount of seconds defined by the enable-delay argument before enabling the secondary line. If, after the delay period, the primary line is still down, the secondary line is activated.
When a primary line comes back up, the software will delay the amount of seconds defined by the disable-delay argument.
In cases where spurious signal disruptions might appear as intermittent lost carrier signals, it is recommended that some delay be enabled before activating and deactivating a secondary.
ExamplesThe following example sets a 10-second delay on deactivating the secondary line; however, the line is activated immediately:
interface serial 0backup delay 0 10The same example on the Cisco 7000 requires the following commands:
backup interface serial
To configure the serial interface as a secondary, or dial backup line, use the backup interface serial interface configuration command. Use the no form of this command to turn disable this feature.
backup interface serial number
backup interface serial slot/port (for the Cisco 7000 series and 7200 series)
no backup interface serial number
no backup interface serial slot/port (for the Cisco 7000 series and 7200 series)Syntax Description
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.0. (An earlier command, backup interface, first appeared in Cisco IOS Release 10.0.)
Examples
The following example sets serial 1 as the backup line to serial 0:
interface serial 0backup interface serial 1Related Command
down-when-looped
backup load
To set the traffic load thresholds for dial backup service, use the backup load interface configuration command. Use the no form of this command to remove the setting.
backup load {enable-threshold | never} {disable-load | never}
no backup load {enable-threshold | never} {disable-load | never}Syntax Description
Default
Both arguments default to never.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When the transmitted or received load on the primary line is greater than the value assigned to the enable-threshold argument, the secondary line is enabled.
When the transmitted load on the primary line plus the transmitted load on the secondary line is less than the value entered for the disable-load argument, and the received load on the primary line plus the received load on the secondary line is less than the value entered for the disable-load argument, the secondary line is disabled.
If the never keyword is used instead of an enable-threshold value, the secondary line is never activated because of load. If the never keyword is used instead of a disable-load value, the secondary line is never deactivated because of load.
Examples
The following example sets the traffic load threshold to 60 percent on the primary line. When that load is exceeded, the secondary line is activated, and will not be deactivated until the combined load is less than 5 percent of the primary bandwidth.
interface serial 0backup load 60 5The same example on the Cisco 7000 requires the following commands:
bandwidth
To set a bandwidth value for an interface, use the bandwidth interface configuration command. Use the no form of this command to restore the default values.
bandwidth kilobits
no bandwidthSyntax Description
kilobits
Intended bandwidth in kilobits per second. For a full bandwidth DS3, enter the value 44736.
Default
Default bandwidth values are set during startup and can be displayed with the EXEC command show interfaces.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The bandwidth command sets an informational parameter only; you cannot adjust the actual bandwidth of an interface with this command. For some media, such as Ethernet, the bandwidth is fixed; for other media, such as serial lines, you can change the actual bandwidth by adjusting hardware. For both classes of media, you can use the bandwidth configuration command to communicate the current bandwidth to the higher-level protocols.
Additionally, IGRP uses the minimum path bandwidth to determine a routing metric. The TCP protocol adjusts initial retransmission parameters based on the apparent bandwidth of the outgoing interface.
At higher bandwidths, the value you configure with the bandwidth command is not what is displayed by the show interface command. The value shown is that used in IGRP updates and also used in computing load.
Note
Example
The following example sets the full bandwidth for DS3 transmissions:
interface serial 0 bandwidth 44736Related Command
A dagger (†) indicates that the command is documented outside this chapter.
vines metric †
cablelength
To increase the pulse of a signal at the receiver and decrease the pulse from the transmitter using pulse equalization and line build-out for a T1 cable on a Cisco AS5200, use the cablelength controller configuration command. To return the pulse equalization and line build-out values to their default settings, use the no form of this command.
cablelength long dbgain-value dbloss-value
no cablelength longSyntax Description
Default
Long cable length, receiver gain of 36 dB, and transmitter loss of 0 dB
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Use this command for configuring the T1 controller only if the Cisco AS5200's T1 line does not connect to an external CSU box. Ask your telephone service provider what decibel option to use when connecting the T1 line to a smart jack.
A pulse equalizer regenerates a signal that has been attenuated and filtered by a cable loss. Pulse equalization does not produce a simple gain, but it filters the signal to compensate for complex cable loss. A gain26 receiver gain compensates for a long cable length equivalent to 26 dB of loss, while a gain36 compensates for 36 dB of loss.
The lengthening or building out of a line is used to control far-end crosstalk. Building out attenuates the stronger signal from the customer installation transmitter so that the transmitting and receiving signals have similar amplitudes. A signal difference of less than 7.5 dB is ideal. Building out does not produce simple flat loss (also known as resistive flat loss). Instead, it simulates a cable loss of 7.5 dB, 15 dB, or 22.5 dB so that the resulting signal is handled properly by the receiving equalizer at the other end.
Example
The following example increases the receiver gain by 26 decibels and decreases the transmitting pulse by 7.5 decibels for a long cable:
cablelength long gain26 -7.5dbcas-group
To configure channelized T1 timeslots with channel associated signaling (also known as robbed bit signaling), which enables an integrated modem to receive and transmit analog calls, use the cas-group controller configuration command. Use the no form of this command to disable channel associated signaling for one or more timeslots.
cas-group channel-group [timeslots range]
no cas-group channel-group [timeslots range]Syntax Description
Default
Disabled
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Use this command to enable an AS5200 modem to receive and send incoming and outgoing analog calls through each T1 controller that is configured for a channelized T1 line, which has 24 possible channels.
Switched 56 digital calls are not supported under this new feature.
Example
The following example shows you how to configure all 24 channels to support robbed bit signaling on a Cisco AS5200:
AS5200(config)# controller T1 0AS5200(config-controller)# cas-group 1 timeslots 1-24AS5200(config-controller)#%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 1 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 2 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 3 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 4 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 5 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 6 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 7 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 8 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 9 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 10 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 11 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 12 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 13 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 14 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 15 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 16 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 17 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 18 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 19 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 20 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 21 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 22 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 23 is up%DSX0-5-RBSLINEUP: RBS of controller 1 timeslot 24 is upchannel-group
Use the channel-group controller configuration command to define the timeslots that belong to each T1 or E1 circuit.
channel-group number timeslots range [speed {48 | 56 | 64}]
Syntax Description
Default
The default line speed when configuring a T1 controller is 56 kbps.
The default line speed when configuring an E1 controller is 64 kbps.
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command in configurations where the router or access server must communicate with a T1 or E1 fractional data line. The channel-group number may be arbitrarily assigned and must be unique for the controller. The timeslot range must match the timeslots assigned to the channel group. The service provider defines the timeslots that comprise a channel group.
Example
In the following example, three channel groups are defined. Channel-group 0 consists of a single timeslot, channel-group 8 consists of 7 timeslots and runs at a speed of 64 kbps per timeslot, and channel-group 12 consists of a single timeslot.
channel-group 0 timeslots 1channel-group 8 timeslots 5,7,12-15,20 speed 64channel-group 12 timeslots 2Related Commands
framing
linecodeclear controller
Use the clear controller EXEC command to reset the T1 or E1 controller on the Cisco 7000 series, Cisco 7200 series, or Cisco 4000 series routers.
clear controller {t1 | e1} slot/port (Cisco 7000 series and Cisco 7200 series)
clear controller {t1 | e1} number (Cisco 4000 series)Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0 (for the Cisco 7000).
This command first appeared in Cisco IOS Release 11.0 (for the Cisco 4000).Examples
The following example resets the T1 controller at slot 4, port 0 on a Cisco 7000 series router:
clear controller t1 4/0The following example resets the E1 controller at NIM 0 on a Cisco 4000 series router:
clear controller e1 0Related Commands
controller e1
controller t1clear controller lex
To reboot the LAN Extender chassis and restart its operating software, use the clear controller lex privileged EXEC command.
clear controller lex number [prom]
clear controller lex slot/port [prom] (for the Cisco 7000 family)Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
The clear controller lex command halts operation of the LAN Extender and performs a cold restart.
Without the prom keyword, if an image exists in Flash memory, and that image has a newer software version than the PROM image, and that image has a valid checksum, then this command runs the Flash image. If any one of these three conditions is not met, this command reloads the PROM image.
With the prom keyword, this command reloads the PROM image, regardless of any Flash image.
Examples
The following example halts operation of the LAN Extender bound to LAN Extender interface 2 and causes the LAN Extender to perform a cold restart from Flash memory:
Router# clear controller lex 2reload remote lex controller? [confirm] yesThe following example halts operation of the LAN Extender bound to LAN Extender interface 2 and causes the LAN Extender to perform a cold restart from PROM:
Router# clear controller lex 2 promreload remote lex controller? [confirm] yesclear counters
To clear the interface counters, use the clear counters EXEC command.
clear counters [type number]
clear counters [type slot/port] [ethernet | serial] (for the Cisco 4000 series or Cisco 7000 series with a LAN Extender interface)
clear counters [type slot/port] (for the Cisco 7000 series and Cisco 7200 series, and for the Cisco 7500 with a Packet over SONET Interface Processor)
clear counters [type slot/port-adapter/port] (for the Cisco 7000 series and the Cisco 7500 series with ports on VIP cards)Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command clears all the current interface counters from the interface unless the optional arguments type and number are specified to clear only a specific interface type (serial, Ethernet, Token Ring, and so on).
Note
Examples
The following example illustrates how to clear all interface counters:
clear countersThe following example illustrates how to clear interface counters on the serial interface residing on a Cisco 1000 series LAN Extender:
clear counters lex 0 serialRelated Command
show interfaces
clear hub
To reset and reinitialize the hub hardware connected to an interface of a Cisco 2505 or Cisco 2507, use the clear hub ethernet EXEC command.
clear hub ethernet number
ethernet
Indicates the hub in front of an Ethernet interface.
number
Hub number to clear, starting with 0. Since there is currently only one hub, this number is 0.
Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Example
The following example clears hub 0:
clear hub ethernet 0Related Command
hub
clear hub counters
To set to zero the hub counters on an interface of a Cisco 2505 or Cisco 2507, use the clear hub counters EXEC command.
clear hub counters [ether number [port [end-port]]]
Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Example
The following example clears the counters displayed in a show hub command for all ports on hub 0:
clear hub counters ether 0Related Command
show hub
clear interface
To reset the hardware logic on an interface, use the clear interface EXEC command.
clear interface type number
clear interface type slot/port (on a Cisco 7000 series and Cisco 7200 series, and for the Cisco 7500 with a Packet over SONET Interface Processor)
clear interface [type slot/port-adapter/port] (for ports on VIP cards in the Cisco 7000 series and the Cisco 7500 series routers)
clear interface type slot/port [:channel-group] (on a Cisco 7000 MIP T1 interface)Syntax Description
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Under normal circumstances, you do not need to clear the hardware logic on interfaces.
Example
The following example resets the interface logic on HSSI interface 1:
clear interface hssi 1clear interface fastethernet
To reset the controller for a specified Fast Ethernet interface, use the clear interface fastethernet privileged EXEC command.
clear interface fastethernet number (Cisco 4500 series)
clear interface fastethernet slot/port (Cisco 7000 series and Cisco 7200 series)
clear interface fastethernet slot/port-adapter/port (Cisco 7500 series)Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Examples
The following example resets the controller for the Ethernet 0 interface on a Cisco 4500:
clear interface fastethernet 0The following example resets the controller for the Ethernet interface located in slot 1 port 0 on a Cisco 7000 or Cisco 7200:
clear interface fastethernet 1/0The following example resets the controller for the Ethernet interface located in slot 1 port adapter 0 port 0 on a Cisco 7500:
clear interface fastethernet 1/0/0clear line
To return a line to its idle state, use the clear line privileged EXEC command at the system prompt.
clear line line-number
Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Normally, this command returns the line to its default as a terminal line, with the interface in a "down" state.
Example
The following example shows how to use the clear line command to return serial interface 5 to its idle state:
clear line 5clear rif-cache
To clear entries from the Routing Information Field (RIF) cache, use the clear rif-cache EXEC command.
clear rif-cache
Syntax Description
This command has no arguments or keywords.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example illustrates how to clear the RIF cache:
clear rif-cacheRelated Command
A dagger (†) indicates that the command is documented outside this chapter.
multiring †
clear service-module serial
To reset the integrated CSU/DSU on a Cisco 2524 or Cisco 2525 router, use the clear service-module serial privileged EXEC configuration command.
clear service-module serial number
Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Use this command only in severe circumstances (for example, when the router is not responding to a CSU/DSU configuration command).
This command terminates all DTE and line loopbacks that are locally or remotely configured. It also interrupts data transmission through the router for up to 15 seconds. The software performs an automatic software reset in case of two consecutive configuration failures.
The CSU/DSU module is not reset with the clear interface command.
CautionIf you experience technical difficulties with your router and intend to contact customer support, refrain from using this command. This command erases the router's past CSU/DSU performance statistics. To clear only the CSU/DSU performance statistics, issue the clear counters command.
Example
The following example resets the CSU/DSU on a Cisco 2524 or Cisco 2525 router:
clear service-module serial 0Related Commands
clear counters
test service-moduleclock rate
To configure the clock rate for the hardware connections on the serial interface appliques, network interface modules (NIMs), and interface processors to an acceptable bit rate, use the clock rate interface configuration command. Use the no clock rate command to remove the clock rate if you change the interface from a DCE to a DTE device.
clock rate bps
no clock rateSyntax Description
bps
Desired clock rate in bits per second: 1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000, 72000, 125000, 148000, 500000, 800000, 1000000, 1300000, 2000000, or 4000000.
Default
No clock rate is configured.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Be aware that the fastest speeds might not work if your cable is too long, and that speeds faster than 148,000 bits per second are too fast for EIA/TIA-232 signaling. It is recommended that you only use the synchronous serial EIA/TIA-232 signal at speeds up to 64,000 bits per second. To permit a faster speed, use an EIA/TIA-449 or V.35 applique.
Example
The following example sets the clock rate on the first serial interface to 64,000 bits per second:
interface serial 0 clock rate 64000clock source (Cisco AS5200)
To select the clock source for the time-division multiplexing (TDM) bus in a Cisco AS5200 access server, use the clock source interface configuration command. The no form of this command configures the clock source to its default setting.
clock source {line {primary | secondary} | internal}
no clock source line {primary | secondary}Syntax Description
Defaults
Primary TDM clock source from the T1 0 controller
Secondary TDM clock source from the T1 1 controller
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
To use the clocking coming in from a T1 line, configure the clock source line primary command on the T1 interface that has the most reliable clocking. Configure the clock source line secondary command on the T1 interface that has the next best known clocking. With this configuration, the primary line clocking is backed up to the secondary line if the primary clocking shuts down.
Example
The following example configures the Cisco AS5200 access server to use T1 controller 0 as the primary clock source and T1 controller 1 as the secondary clock source:
controller t1 0clock source line primarycontroller t1 1clock source line secondaryclock source (controller)
Use the clock source controller configuration command to set the T1-line clock-source for the MIP in the Cisco 7000 series, Cisco 7200 series, and Cisco 7500 series or for the NPM in the Cisco 4000 series.
clock source {line | internal}
Syntax Description
line
Specifies the T1 line as the clock source.
internal
Specifies the MIP (Cisco 7000 series, Cisco 7200 series, and Cisco 7500 series) or the NPM (Cisco 4000) as the clock source.
Defaults
Primary TDM clock source from the T0 controller
Secondary TDM clock source from the T1 controller
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
To use the clocking coming in from a T1 line, configure the clock source line primary command on the controller that has the most reliable clocking. Configure the clock source line secondary command on the controller that has the next best known clocking. With this configuration, the primary line clocking is backed up to the secondary line if the primary clocking shuts down.
Example
The following example configures the Cisco AS5200 to use the T0 controller as the primary clocking source and the T1 controller as the secondary clocking source:
AS5200(config)# controller t1 0AS5200(config-if)# clock source line primaryAS5200(config-if)# exitAS5200(config)# controller t1 1AS5200(config-if)# clock source line secondaryRelated Commands
framing
linecodeclock source (interface)
To control which clock a G.703 E1 interface will use to clock its transmitted data from, use the clock source interface configuration command. The no form of this command restores the default value.
clock source {line | internal}
no clock sourceSyntax Description
Default
By default, the applique uses the line's receive data stream.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
This command applies to a Cisco 4000 router or Cisco 7000 series and Cisco 7500 series router. A G.703-E1 interface can clock its transmitted data from either its internal clock or from a clock recovered from the line's receive data stream.
Example
The following example specifies the G.703-E1 interface to clock its transmitted data from its internal clock:
clock source internalcmt connect
To start the processes that perform the connection management (CMT) function and allow the ring on one fiber to be started, use the cmt connect EXEC command.
cmt connect [interface-name [phy-a | phy-b]]
Syntax Description
interface-name
(Optional) Specifies the FDDI interface.
phy-a
(Optional) Selects Physical Sublayer A.
phy-b
(Optional) Selects Physical Sublayer B.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
In normal operation, the FDDI interface is operational once the interface is connected and configured. The cmt connect command allows the operator to start the processes that perform the CMT function.
The cmt connect command is not needed in the normal operation of FDDI; this command is used mainly in interoperability tests.
Examples
The following examples demonstrate use of the cmt connect command for starting the CMT processes on the FDDI ring.
The following command starts all FDDI interfaces:
cmt connectThe following command starts both fibers on the FDDI interface unit 0:
cmt connect fddi 0The following command on the Cisco 7000 series, the Cisco 7200 series, or Cisco 7500 series starts both fibers on the FDDI interface unit 0:
cmt connect fddi 1/0The following command starts only Physical Sublayer A on the FDDI interface unit 0:
cmt connect fddi 0 phy-aThe following command on the Cisco 7000 starts only Physical Sublayer A on the FDDI interface unit 0:
cmt connect fddi 1/0 phy-acmt disconnect
To stop the processes that perform the connection management (CMT) function and allow the ring on one fiber to be stopped, use the cmt disconnect EXEC command.
cmt disconnect [interface-name [phy-a | phy-b]]
Syntax Description
interface-name
(Optional) Specifies the FDDI interface.
phy-a
(Optional) Selects Physical Sublayer A.
phy-b
(Optional) Selects Physical Sublayer B.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
In normal operation, the FDDI interface is operational once the interface is connected and configured, and is turned off using the shutdown interface configuration command. The cmt disconnect command allows the operator to stop the processes that perform the CMT function and allow the ring on one fiber to be stopped.
The cmt disconnect command is not needed in the normal operation of FDDI; this command is used mainly in interoperability tests.
Examples
The following examples demonstrate use of the cmt disconnect command for stopping the CMT processes on the FDDI ring.
The following command stops all FDDI interfaces:
cmt disconnectThe following command stops both fibers on the FDDI interface unit 0:
cmt disconnect fddi 0The following command on the Cisco 7000 series, the Cisco 7200 series, or Cisco 7500 series stops both fibers on the FDDI interface unit zero:
cmt disconnect fddi 1/0The following command stops only Physical Sublayer A on the FDDI interface unit 0. This command causes the FDDI media to go into a wrapped state so that the ring will be broken.
cmt disconnect fddi 0 phy-aThe following command on the Cisco 7000 series or Cisco 7500 series stops only Physical Sublayer A on the FDDI interface unit 0 in slot 1. This command causes the FDDI media to go into a wrapped state so that the ring will be broken.
cmt disconnect fddi 1/0 phy-acompress
To configure software compression for Link Access Procedure, Balanced (LAPB), and High-Level Data Link Control (HDLC) encapsulations, use the compress interface configuration command. To disable compression, use the no form of this command.
compress [predictor | stac]
no compress [predictor | stac]Syntax Description
predictor
(Optional) Specifies that a predictor compression algorithm will be used.
stac
(Optional) Specifies that a Stacker (LZS) compression algorithm will be used.
Default
Compression is disabled.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0 (as compress predictor). The command, compress predictor stac first appeared in Cisco IOS Release 10.3.
You can configure point-to-point software compression for all LAPB, PPP, and HDLC encapsulations. Compression reduces the size of frames via lossless data compression. The compression algorithm used is a predictor algorithm (the RAND compression algorithm), which uses a compression dictionary to predict what the next character in the frame will be.
For HDLC encapsulations, you can specify a Stacker compression algorithm by using the stac keyword. PPP and LAPB encapsulations support both predictor and Stacker compression algorithms.
Compression is performed in software and may significantly affect system performance. We recommend that you disable compression if CPU load exceeds 65 percent. To display the CPU load, use the show process cpu EXEC command.
Compression requires that both ends of the serial link be configured to use compression. You should never enable compression for connections to a public data network.
Note
If the majority of your traffic is already compressed files, we recommend that you not use compression. If the files are already compressed, the additional processing time spent in attempting unsuccessfully to compress them again will slow system performance.
provides general guidelines for deciding which compression type to select for LAPB encapsulations.
Stacker compression for LAPB encapsulations reaches its performance ceiling on T1 lines; it is not recommended for faster lines because the added processing slows their performance. Stacker compression processing might be slower on other systems than on the Cisco 4500 routers.
When using predictor compression, you can adjust the MTU for the serial interface and the LAPB maximum bits per frame (N1) parameter, as shown in the first example, to avoid informational diagnostics regarding excessive MTU or N1 sizes. However, you should not change those parameters when you use Stacker compression.
Examples
The following example enables predictor compression on serial interface 0 for a LAPB link:
interface serial 0encapsulation lapbcompress predictormtu 1509lapb n1 12072The following example enables Stacker compression on serial interface 0 for a LAPB link. This example does not set the MTU size and the maximum bits per frame (N1); we recommend that you do not change those LAPB parameters for Stacker compression:
interface serial 0encapsulation lapbcompress predictorRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
encapsulation lapb
encapsulation x25
show compress
show processes †controller
To configure a T1 or E1 controller and enter controller configuration mode, use the controller global configuration command.
controller {t1 | e1} slot/port (on the Cisco 7000 and the Cisco 7500 series)
controller {t1 | e1} number (on the Cisco 4000 series)
Syntax Description
Default
No T1 or E1 controller is configured.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0 (for the Cisco 7000 and 7500 series).
This command first appeared in Cisco IOS Release 11.0 (for the Cisco 4000).This command is used in configurations where the router or access server is intended to communicate with a T1 or E1 fractional data line. Additional parameters for the T1 or E1 line must be configured for the controller before the T1 or E1 circuits can be configured by means of the interface global configuration command.
This command is used only on a Cisco 7000 series and Cisco 7500 series or Cisco 4000 series router.
This command does not apply to the Cisco 7200 series.
Examples
In the following example, the MIP in slot 4, port 0 of a Cisco 7000 is configured as a T1 controller:
controller t1 4/0In the following example, NIM 0 of a Cisco 4000 is configured as a T1 controller:
controller t1 0Related Commands
channel-group
clear controller lex
clear controller t1
clock source (controller)
framing
linecode
show controllers e1
show controller t1copy flash lex
To download an executable image from Flash memory on the core router to the LAN Extender chassis, use the copy flash lex privileged EXEC command.
copy flash lex number
Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
If you attempt to download a version of the software older than what is currently running on the LAN Extender, a warning message is displayed.
Example
The following example illustrates how to copy the executable image namexx to the LAN Extender interface 0:
Router# copy flash lex 0Name of file to copy? namexxAddress of remote host [255.255.255.255] <cr>writing namexx !!!!!!!!!!!!!!!!!!!!!!!!!copy completeRelated Command
copy tftp lex
copy tftp lex
To download an executable image from a TFTP server to the LAN Extender, use the copy tftp lex privileged EXEC command.
copy tftp lex number
Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
If you attempt to download a version of the software older than what is currently running on the LAN Extender, a warning message is displayed.
Example
The following example illustrates how to copy the file namexx from the TFTP server:
Router# copy tftp lex 0Address or name of remote host (255.255.255.255]? 131.108.1.111Name of file to copy? namexxOK to overwrite software version 1.0 with 1.1 ?[confirm]Loading namexx from 131.108.13.111!!!!!!!!!!!!!!!!!!!!!!!!![OK - 127825/131072 bytes]Successful download to LAN Extendercrc
To set the length of the cyclic redundancy check (CRC) on a Fast Serial Interface Processor (FSIP) or HSSI Interface Processor (HIP) of the Cisco 7000 series and Cisco 7500 series or on a 4-port serial adapter of the Cisco 7200 series, use the crc interface configuration command. To set the CRC length to 16 bits, use the no form of this command.
crc size
no crcSyntax Description
Default
16 bits
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
All interfaces use a 16-bit cyclic redundancy check (CRC) by default, but also support a 32-bit CRC. CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The designators 16 and 32 indicate the length (in bits) of the frame check sequence (FCS). A CRC of 32 bits provides more powerful error detection, but adds overhead. Both the sender and receiver must use the same setting.
CRC-16, the most widely used throughout the United States and Europe, is used extensively with wide-area networks (WANs). CRC-32 is specified by IEEE 802 and as an option by some point-to-point transmission standards. It is often used on SMDS networks and LANs.
Example
In the following example, the 32-bit CRC is enabled on serial interface 3/0:
interface serial 3/0crc 32crc4
To enable generation of CRC4 on the G.703 E1 port adapter on the FSIP, use the crc4 interface configuration command. To disable this feature, use the no form of this command.
crc4
no crc4Syntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
This command applies to a Cisco 4000 router or Cisco 7000 series and Cisco 7500 series router. It is useful for checking data integrity while operating in framed mode. CRC4 provides additional protection for a frame alignment signal under noisy conditions. Refer to CCITT Recommendation G.704 for a definition of CRC4.
This command does not apply to the Cisco 7200 series.
Example
The following example enables CRC4 generation on the G.703 E1 port adapter on the FSIP:
crc4dce-terminal-timing enable
When running the line at high speeds and long distances, use the dce-terminal-timing enable interface configuration command to prevent phase shifting of the data with respect to the clock. If SCTE is not available from the DTE, use no form of this command, which causes the DCE to use its own clock instead of SCTE from the DTE.
dce-terminal-timing enable
no dce-terminal-timing enableSyntax Description
This command has no keywords or arguments.
Default
DCE uses its own clock.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
On the Cisco 4000 platform, you can specify the serial Network Interface Module timing signal configuration. When the board is operating as a DCE and the DTE provides terminal timing (SCTE or TT), the dce-terminal-timing enable command causes the DCE to use SCTE from the DTE.
Example
The following example prevents phase shifting of the data with respect to the clock:
interface serial 0 dce-terminal-timing enabledelay
To set a delay value for an interface, use the delay interface configuration command. Use the no form of this command to restore the default delay value.
delay tens-of-microseconds
no delaySyntax Description
tens-of-microseconds
Integer that specifies the delay in tens of microseconds for an interface or network segment.
Default
Default delay values may be displayed with the EXEC command show interfaces.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example sets a 30,000-microsecond delay on serial interface 3:
interface serial 3 delay 30000Related Command
show interfaces
description (controller)
To add a description to an E1 or T1 controller on a Cisco 7000 series and Cisco 7500 series router, use the description controller configuration command. Use the no form of this command to remove the description.
description string
no descriptionSyntax Description
Default
No description is added.
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
The description command is meant solely as a comment to be put in the configuration to help you remember what certain E1 or T1 controllers are used for. The description affects the MIP interfaces only and appears in the output of the show controllers e1, show controllers t1, and show running-config EXEC commands.
Example
The following example describes a 3174 controller:
controller t1 description 3174 Controller for test labRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
show controllers e1
show controller t1
show running-config †description (interface)
To add a description to an interface configuration, use the description interface configuration command. Use the no form of this command to remove the description.
description string
no descriptionSyntax Description
Default
No description is added.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The description command is meant solely as a comment to be put in the configuration to help you remember what certain interfaces are used for. The description appears in the output of the following EXEC commands: show startup-config, show interfaces, and show running-config.
Example
The following example shows how to add a description for a T1 interface:
interface serial 0 description Fractional T1 line to Mountain View -- 128 Kb/sRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
show interfaces
show running-config †
show startup-config †down-when-looped
To configure an interface to inform the system it is down when loopback is detected, use the down-when-looped interface configuration command.
down-when-looped
Syntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command is valid for HDLC or PPP encapsulation on serial and HSSI interfaces.
When an interface has a backup interface configured, it is often desirable that the backup interface be enabled when the primary interface is either down or in loopback. By default, the backup is only enabled if the primary interface is down. By using the down-when-looped command, the backup interface will also be enabled if the primary interface is in loopback.
If testing an interface with the loopback command, or by placing the DCE into loopback, down-when-looped should not be configured; otherwise, packets will not be transmitted out the interface that is being tested.
Example
In the following example, interface serial 0 is configured for HDLC encapsulation. It is then configured to let the system know that it is down when in loopback mode.
interface serial0encapsulation hdlcdown-when-loopedRelated Commands
backup interface serial
loopback (interface)dte-invert-txc
On the Cisco 4000 series, you can specify the serial Network Processor Module timing signal configuration. When the board is operating as a DTE, the dte-invert-txc command inverts the TXC clock signal it gets from the DCE that the DTE uses to transmit data. Use the no form of this command if the DCE accepts SCTE from the DTE.
dte-invert-txc
no dte-invert-txcSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command if the DCE cannot receive SCTE from the DTE, the data is running at high speeds, and the transmission line is long. This prevents phase shifting of the data with respect to the clock.
If the DCE accepts SCTE from the DTE, use no dte-invert-txc.
Example
The following example inverts the TXC on serial interface 0:
interface serial 0 dte-invert-txcearly-token-release
To enable early token release on Token Ring interfaces, use the early-token-release interface configuration command. Once enabled, use the no form of this command to disable this feature.
early-token-release
no early-token-releaseSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Early token release is a method whereby the Token Ring interfaces can release the token back onto the ring immediately after transmitting, rather than waiting for the frame to return. This feature helps increase the total bandwidth of the Token Ring.
The Token Ring Interface Processor (TRIP) on the Cisco 7000 series and Cisco 7500 series and the Token Ring adapters on the Cisco 7200 series all support early token release.
Examples
The following example enables the use of early token release on Token Ring interface 1:
interface tokenring 1early-token-releaseOn the Cisco 7000 series, to enable the use of early token release on your Token Ring interface processor in slot 4 on port 1, issue the following configuration commands:
interface tokenring 4/1early-token-releaseencapsulation
To set the encapsulation method used by the interface, use the encapsulation interface configuration command.
encapsulation encapsulation-type
Syntax Description
Default
The default depends on the type of interface. For example, a synchronous serial interface defaults to HDLC.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
To use SLIP or PPP, the router or access server must be configured with an IP routing protocol or with the ip host-routing command. This configuration is done automatically if you are using old-style slip address commands. However, you must configure it manually if you configure SLIP or PPP via the interface async command.
Examples
The following example resets HDLC serial encapsulation on serial interface 1:
interface serial 1 encapsulation hdlcThe following example enables PPP encapsulation on serial interface 0:
interface serial 0encapsulation pppRelated Commands
The dagger (†) indicates that the command is documented outside this chapter.
keepalive
ppp †
ppp authentication †
slip †encapsulation atm-dxi
Use the encapsulation atm-dxi interface configuration command to enable ATM-DXI encapsulation. The no form of this command disables ATM-DXI.
encapsulation atm-dxi
no encapsulation atm-dxiSyntax Description
This command has no arguments or keywords.
Default
HDLC
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example configures ATM-DXI encapsulation on serial interface 1:
interface serial 1 encapsulation atm-dxiRelated Command
atm-dxi map
encapsulation lapb
To set the LAPB encapsulation method used by the interface, use the encapsulation lapb interface configuration command.
encapsulation lapb [dte | dce] [multi | protocol]
Syntax Description
Default
DTE is the default operational type.
IP is the default protocol type.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0. (The options first appeared in Cisco IOS Release 10.3.)
To use a particular encapsulation, you must configure the router or access server with that protocol type.
Example
The following example enables LAPB encapsulation on serial interface 0, using a default IP routing protocol:
interface serial 0encapsulation lapbencapsulation x25
To specify an serial interface's operation as an X.25 device, use the encapsulation x25 interface configuration command.
encapsulation x25 [dte | dce] [ddn | bfe | ietf]
Syntax Description
Defaults
The default serial encapsulation is HDLC. You must explicitly configure an X.25 encapsulation method.
DTE operation is the default X.25 mode. Cisco's traditional X.25 encapsulation method is the default.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0 (with the dce option). The remaining options first apeared in Cisco IOS Release 10.3.
One end of an X.25 link must be a logical DCE and the other end a logical DTE. (This assignment is independent of the interface's hardware DTE/DCE identity.) Typically, when connecting to a public data network (PDN), the customer equipment acts as the DTE and the PDN attachment acts as the DCE.
Cisco has supported the encapsulation of a number of datagram protocols for quite some time, using a standard means when available and proprietary means when necessary. More recently the IETF adopted a standard, RFC 1356, for encapsulating most types of datagram traffic over X.25. X.25 interfaces use Cisco's traditional method unless explicitly configured for IETF operation; if the ietf keyword is specified, that standard will be used unless Cisco's traditional method is explicitly configured. For details see the x25 map command.
When an X.25 interface is reconfigured, all of the interface's X.25 parameters are initialized except the x25 map commands. The x25 map statements that are configured for an interface are not deleted when the encapsulation is changed, so they will be retained if the interface is later reconfigured for X.25 operation.
A router or access server attaching to the Defense Data Network (DDN) or to a Blacker Front End (BFE) device can be configured to use their respective algorithms to convert between IP and X.121 addresses by using the ddn or bfe options, respectively. An IP address should be assigned to the interface, from which the algorithm will generate the interface's X.121 address; for proper operation, this X.121 address should not be modified.
A router or access server DDN attachment can operate as either a DTE or a DCE device. A BFE attachment can operate only as a DTE device. The ietf option is not available if either the ddn or bfe option is selected.
Example
The following example configures the interface for connection to a Blacker Front End device:
interface serial 0encapsulation x25 bfeerror-threshold
To set the mechanism that protects against packet overload and resulting recount errors on the MCI interface cards, use the error-threshold interface configuration command.
error-threshold milliseconds
Syntax Description
Default
1000 ms
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following commands set the error recount threshold on Ethernet interface 2 to 10,000 ms:
interface ethernet 2 error-threshold 10000fddi burst-count
To allow the FCI card to preallocate buffers to handle bursty FDDI traffic (for example, NFS bursty traffic), use the fddi burst-count interface configuration command. Use the no form of this command to revert to the default value.
fddi burst-count number
no fddi burst-countSyntax Description
Default
3 buffers
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command applies to the FCI card only. The microcode software version should not be 128.45 or 128.43.
Example
The following example sets the number of buffers to 5:
interface fddi 0 fddi burst-count 5fddi c-min
To set the C-Min timer on the PCM, use the fddi c-min interface configuration command. Use the no form of this command to revert to the default value.
fddi c-min microseconds
no fddi c-minSyntax Description
Default
1600 microseconds
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command applies to the processor CMT only. You need extensive knowledge of the PCM state machine to tune this timer. Use this command when you run into PCM interoperability problems.
Example
The following example sets the C-Min timer to 2000 microseconds:
interface fddi 0 fddi c-min 2000Related Commands
fddi tb-min
fddi tl-min-time
fddi t-outfddi cmt-signal-bits
To control the information transmitted during the connection management (CMT) signaling phase, use the fddi cmt-signal-bits interface configuration command.
fddi cmt-signal-bits signal-bits [phy-a | phy-b]
Syntax Description
Defaults
The default signal bits for the phy-a and phy-b keywords are as follows:
•
•
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
If neither the phy-a nor phy-b keyword is specified, the signal bits apply to both physical connections.
Note
Use and to set the physical type and duration bits.
Table 21 FDDI Physical Type Bit Specifications
0
0
Physical A
1
0
Physical B
0
1
Physical S
1
1
Physical M
Example
The following example sets the CMT signaling phase to signal bits 0x208 on both physical connections:
interface fddi 0 fddi cmt-signal-bits 208fddi duplicate-address-check
To turn on the duplicate address detection capability on the FDDI, use the fddi duplicate-address-check interface configuration command. Use the no form of this command to disable this feature.
fddi duplicate-address-check
no fddi duplicate-address-checkSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
If you use this command, the Cisco IOS software will detect a duplicate address if multiple stations are sharing the same MAC address. If the software finds a duplicate address, it will shut down the interface.
Example
The following example enables duplicate address checking on the FDDI:
interface fddi 0 fddi duplicate-address-checkfddi encapsulate
To specify encapsulating bridge mode on the CSC-C2/FCIT interface card, use the fddi encapsulate interface configuration command. Use the no form of this command to turn off encapsulation bridging and return the FCIT interface to its translational, nonencapsulating mode.
fddi encapsulate
no fddi encapsulateSyntax Description
This command has no arguments or keywords.
Default
The FDDI interface by default uses the SNAP encapsulation format defined in RFC 1042. It is not necessary to define an encapsulation method for this interface when using the CSC-FCI interface card.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The no fddi encapsulate command applies only to CSC-C2/FCIT interfaces, because the CSC-FCI interfaces are always in encapsulating bridge mode. The CSC-C2/FCIT interface card fully supports transparent and translational bridging for the following configurations:
•
•
•
The command fddi encapsulate puts the CSC-C2/FCIT interface into encapsulation mode when doing bridging. In transparent mode, the FCIT interface interoperates with earlier versions of the CSC-FCI encapsulating interfaces when performing bridging functions on the same ring.
CautionBridging between dissimilar media presents several problems that can prevent communications from occurring. These problems include bit-order translation (or usage of MAC addresses as data), maximum transfer unit (MTU) differences, frame status differences, and multicast address usage. Some or all of these problems might be present in a multimedia bridged LAN and might prevent communication from taking place. These problems are most prevalent when bridging between Token Rings and Ethernets or between Token Rings and FDDI nets. This is because of the different way Token Ring is implemented by the end nodes.
The following protocols have problems when bridged between Token Ring and other media: Novell IPX, DECnet Phase IV, AppleTalk, VINES, XNS, and IP. Further, the following protocols may have problems when bridged between FDDI and other media: Novell IPX and XNS. We recommend that these protocols be routed whenever possible.
Example
The following example sets FDDI interface 1 on the CSC-C2/FCIT interface card to encapsulating bridge mode:
interface fddi 1 fddi encapsulatefddi smt-frames
To enable the SMT frame processing capability on the FDDI, use the fddi smt-frames interface configuration command. Use the no form of this command to disable this feature and prevent the Cisco IOS software from generating or responding to SMT frames.
fddi smt-frames
no fddi smt-framesSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use the no form of this command to turn off SMT frame processing for diagnosing purposes. Use the fddi smt-frames command to reenable the feature.
Example
The following example disables SMT frame processing:
interface fddi 0 no fddi smt-framesfddi tb-min
To set the TB-Min timer in the physical connection management (PCM), use the fddi tb-min interface configuration command. Use the no form of this command to revert to the default value.
fddi tb-min milliseconds
no fddi tb-minSyntax Description
Default
100 ms
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
This command applies to the processor CMT only. You need extensive knowledge of the PCM state machine to tune this timer. Use this command when you run into PCM interoperability problems.
Example
The following example sets the TB-Min timer to 200 ms:
interface fddi 0 fddi tb-min 200Related Commands
fddi c-min
fddi tl-min-time
fddi t-outfddi tl-min-time
To control the TL-Min time (the minimum time to transmit a Physical Sublayer, or PHY line state, before advancing to the next physical connection management (PCM) state, as defined by the X3T9.5 specification), use the fddi tl-min-time interface configuration command.
fddi tl-min-time microseconds
Syntax Description
Default
30 microseconds
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Interoperability tests have shown that some implementations of the FDDI standard need more than 30 microseconds to sense a signal.
Examples
The following example changes the TL-Min time from 30 microseconds to 100 microseconds:
interface fddi 0fddi tl-min-time 100The following example changes the TL-Min time from 30 microseconds to 100 microseconds on a Cisco 7000:
interface fddi 3/0fddi tl-min-time 100Related Commands
fddi c-min
fddi tl-min-time
fddi t-outfddi token-rotation-time
To control ring scheduling during normal operation and to detect and recover from serious ring error situations, use the fddi token-rotation-time interface configuration command.
fddi token-rotation-time microseconds
Syntax Description
Default
5000 microseconds
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The FDDI standard restricts the allowed time to be greater than 4000 microseconds and less than 165,000 microseconds. As defined in the X3T9.5 specification, the value remaining in the TRT is loaded into the token holding timer (THT). Combining the values of these two timers provides the means to determine the amount of bandwidth available for subsequent transmissions.
Examples
The following example sets the rotation time to 24,000 microseconds:
interface fddi 0fddi token-rotation-time 24000The following example sets the rotation time to 24,000 microseconds on a Cisco 7000:
interface fddi 3/0fddi token-rotation-time 24000fddi t-out
To set the t-out timer in the physical connection management (PCM), use the fddi t-out interface configuration command. Use the no form of this command to revert to the default value.
fddi t-out milliseconds
no fddi t-outSyntax Description
Default
100 ms
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command applies to the processor CMT only. You need extensive knowledge of the PCM state machine to tune this timer. Use this command when you run into PCM interoperability problems.
Example
The following example sets the timeout timer to 200 ms:
interface fddi 0fddi t-out 200Related Commands
fddi c-min
fddi tb-min
fddi tl-min-timefddi valid-transmission-time
To recover from a transient ring error, use the fddi valid-transmission-time interface configuration command.
fddi valid-transmission-time microseconds
Syntax Description
Default
2500 microseconds
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Examples
The following example changes the transmission timer interval to 3000 microseconds:
interface fddi 0fddi valid-transmission-time 3000The following example changes the transmission timer interval to 3000 microseconds on a Cisco 7000 or Cisco 7200:
interface fddi 3/0fddi valid-transmission-time 3000fdl
To set the facilities data-link exchange standard for the CSU on the T1 controllers on the Cisco AS5200, enter the fdl controller configuration command. To disable facilities data-link support, use the no form of this command.
fdl {att | ansi}
no fdl {att | ansi}Syntax Description
att
Selects AT&T technical reference 54016 for Extended Super Frame facilities data-link exchange support.
ansi
Selects ANSI T1.403 for Extended Super Frame facilities data-link exchange support.
Default
Disabled
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
You must configure this command on both T1 controllers if you want to support the CSU function on each T1 line. However, you must use the same facilities data-link exchange standard as your service provider. You can have a different standard configured on each T1 interface.
Example
The following example configures the ANSI T1.403 standard for T1 controller 0:
controller t1 0fdl ansiframing
Use the framing controller configuration command to select the frame type for the T1 or E1 data line.
framing {sf | esf} (for T1 lines)
framing {crc4 | no-crc4} [australia] (for E1 lines)Syntax Description
Defaults
Super Frame is the default on a T1 line.
CRC4 frame is the default on an E1 line.
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0 as framing {sf | esf}.
Use this command in configurations where the router or access server is intended to communicate with T1 or E1 fractional data line. The service provider determines which framing type, either sf, esf, or crc4, is required for your T1/E1 circuit.
Example
The following example selects Extended Super Frame as the T1 frame type:
framing esfRelated Commands
channel-group
linecodegroup-range
To create a list of member asynchronous interfaces (associated with a group interface), use the group-range interface configuration command. Use the no form of the command to remove an interface from the member list.
group-range low-end-of-range high-end-of-range
no group-number interfaceSyntax Description
Default
No interfaces are designated as members of a group.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Using the group-range command, you create a group of asynchronous interfaces that are associated with a group asynchronous interface on the same device. This group interface is configured by using the interface group-async command. This one-to-many structure allows you to configure all associated member interfaces by entering one command on the group interface, rather than entering this command on each interface. You can customize the configuration on a specific interface by using the member command.
Examples
The following example defines interfaces 2, 3, 4, 5, 6, and 7 as members of asynchronous group interface 0:
interface group-async 0 group range 2 7Related Commands
interface group-async
member
half-duplex
Use the half-duplex interface configuration command to configure an SDLC interface for half-duplex mode. Use the no form of this command to reset the interface for full-duplex mode.
half-duplex
no half-duplexSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
The half-duplex command is used to configure an SDLC interface for half-duplex mode.
The half-duplex command deprecates the both the sdlc hdx and media-type half-duplex commands.
Note
Example
In the following example, an SDLC interface has been configured for half-duplex mode:
encapsulation sdlc-primaryhalf-duplexRelated Command
The dagger (†) indicates that the command is documented outside this chapter.
half-duplex timer †
half-duplex controlled-carrier
To place a low-speed serial interface in controlled-carrier mode, instead of constant-carrier mode, use the half-duplex controlled-carrier interface configuration command. Use the no form of this command to return the interface to constant-carrier mode.
half-duplex controlled-carrier
no half-duplex controlled-carrierSyntax Description
This command has no arguments or keywords.
Default
Constant-carrier mode, where DCD is held constant and asserted by the DCE half-duplex interface.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies only to low-speed serial DCE interfaces in half-duplex mode. Configure a serial interface for half-duplex mode by using the media-type half-duplex command. These interfaces are available on Cisco 2520 through 2523 routers.
Controlled-carrier operation means that the DCE interface will have DCD deasserted in the quiescent state. When the interface has something to transmit, it will assert DCD, wait a user-configured amount of time, then start the transmission. When the interface has finished transmitting, it will again wait a user-configured amount of time, then deassert DCD.
An interface placed in controlled-carrier mode can be returned to constant-carrier mode by using the no form of the command.
Examples
The following examples show how to place the interface in controlled-carrier mode and back into constant-carrier operation.
Changing to controlled-carrier mode from the default of constant-carrier operation:
interface serial 2half-duplex controlled-carrierChanging to constant-carrier operation from controlled-carrier mode:
interface serial 2no half-duplex controlled-carrierRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
half-duplex timer †
physical-layer †hold-queue
To specify the hold-queue limit of an interface, use the hold-queue interface configuration command. Use the no form of this command with the appropriate keyword to restore the default values for an interface.
hold-queue length {in | out}
no hold-queue {in | out}Syntax Description
length
Integer that specifies the maximum number of packets in the queue.
in
Specifies the input queue.
out
Specifies the output queue.
Default
The default input hold-queue limit is 75 packets. The default output hold-queue limit is 40 packets. These limits prevent a malfunctioning interface from consuming an excessive amount of memory. There is no fixed upper limit to a queue size.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The input hold queue prevents a single interface from flooding the network server with too many input packets. Further input packets are discarded if the interface has too many input packets outstanding in the system.
If priority output queueing is being used, the length of the four output queues is set using the priority-list global configuration command. The hold-queue command cannot be used to set an output hold queue length in this situation.
For slow links, use a small output hold-queue limit. This approach prevents storing packets at a rate that exceeds the transmission capability of the link. For fast links, use a large output hold-queue limit. A fast link may be busy for a short time (and thus require the hold queue), but can empty the output hold queue quickly when capacity returns.
To display the current hold queue setting and the number of packets discarded because of hold queue overflows, use the EXEC command show interfaces.
Note
Example
The following example illustrates how to set a small input queue on a slow serial line:
interface serial 0 hold-queue 30 inRelated Command
show interfaces
hssi external-loop-request
To allow the router to support a CSU/DSU that uses the LC signal to request a loopback from the router, use the hssi external-loop-request interface configuration command. Use the no form of this command to disable the feature.
hssi external-loop-request
no hssi external-loop-requestSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The HSA applique (on the HSSI) contains an LED that indicates the LA, LB, and LC signals transiting through the devices. The CSU/DSU uses the LC signal to request a loopback from the router. The CSU/DSU may want to do this so that its own network management diagnostics can independently check the integrity of the connection between the CSU/DSU and the router.
Use this command to enable a two-way, internal, and external loopback request on HSSI from the CSU/DSU.
Note
Example
The following example enables a CSU/DSU to use the LC signal to request a loopback from the router:
hssi external-loop-requesthssi internal-clock
To convert the HSSI interface into a 45 MHz clock master, use the hssi internal-clock interface configuration command. Use the no form of this command to disable the clock master mode.
hssi internal-clock
no hssi internal-clockSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Use this command in conjunction with the HSSI null-modem cable to connect two Cisco routers together with HSSI. You must configure this command at both ends of the link, not just one.
Example
The following example converts the HSSI interface into a 45 MHz clock master:
hssi internal-clockhub
To enable and configure a port on an Ethernet hub of a Cisco 2505 or Cisco 2507, use the hub global configuration command.
hub ethernet number port [end-port]
Syntax Description
Default
No hub ports are configured.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Examples
The following example enables port 1 on hub 0:
hub ethernet 0 1no shutdownThe following example enables ports 1 through 8 on hub 0:
hub ethernet 0 1 8no shutdownRelated Command
shutdown
ignore-dcd
Use the ignore-dcd interface configuration command to configure the serial interface to monitor the DSR signal (instead of the DCD signal) as the line up/down indicator. Use the no form of this command to restore the default behavior.
ignore-dcd
no ignore-dcdSyntax Description
This command has no arguments or keywords.
Default
The serial interface, operating in DTE mode, monitors the DCD signal as the line up/down indicator.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.0.
This command applies to Quad Serial NIM interfaces on the Cisco 4000 series and Hitachi-based serial interfaces on the Cisco 2500 series and Cisco 3000 series.
When the serial interface is operating in DTE mode, it monitors the Data Carrier Detect (DCD) signal as the line up/down indicator. By default, the attached DCE device sends the DCD signal. When the DTE interface detects the DCD signal, it changes the state of the interface to up.
In some configurations, such as an SDLC multidrop environment, the DCE device sends the Data Set Ready (DSR) signal instead of the DCD signal, which prevents the interface from coming up. Use this command to tell the interface to monitor the DSR signal instead of the DCD signal as the line up/down indicator.
Example
The following example configures serial interface 0 to monitor the DSR signal as the line up/down indicator:
interface serial 0ignore-dcdinterface
To configure an interface type and enter interface configuration mode, use the interface global configuration command.
interface type number
interface type slot/port (for the Cisco 7000 series and Cisco 7200 series, and for the Cisco 7500 series with a Packet over SONET Interface Processor)
interface [type slot/port-adapter/port] [ethernet | serial] (for ports on VIP cards in the Cisco 7000 and the 7500 series routers)
interface serial slot/port:channel-group (for channelized T1 or E1 on the Cisco 7000 series)
interface serial number:channel-group (for channelized T1 or E1 on the Cisco 4000 series)To configure a subinterface, use the interface global configuration command.
interface type slot/port-adapter/port.subinterface-number {multipoint | point-to-point} (for ports on VIP cards in the Cisco 7000 and the 7500 series routers)
interface type slot/port.subinterface-number {multipoint | point-to-point} (for the Cisco 7000 series and Cisco 7200 series)
interface type slot/port-adapter.subinterface-number {multipoint | point-to-point} (for the Cisco 7500 series)Syntax Description
Default
None
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0 for the Cisco 7000 series.
This command first appeared in Cisco IOS Release 11.0 for the Cisco 4000 series.Subinterfaces can be configured to support partially meshed Frame Relay networks (refer to the chapter entitled "Configuring Interfaces" in the Configuration Fundamentals Configuration Guide).
There is no correlation between the number of the physical serial interface and the number of the logical LAN Extender interface. These interfaces can have the same or different numbers.
Examples
In the following example, serial interface 0 is configured with PPP encapsulation:
interface serial 0 encapsulation pppThe following example enables loopback mode and assigns an IP network address and network mask to the interface. The loopback interface established here will always appear to be up:
interface loopback 0 ip address 131.108.1.1 255.255.255.0The following example for the Cisco 7000 shows the interface configuration command for Ethernet port 4 on the EIP that is installed in (or recently removed from) slot 2:
interface ethernet 2/4The following example begins configuration on the Token Ring interface processor in slot 1 on
port 0 of a Cisco 7000:interface tokenring 1/0The following example shows how a partially meshed Frame Relay network can be configured. In this example, subinterface serial 0.1 is configured as a multipoint subinterface with three frame relay PVCs associated, and subinterface serial 0.2 is configured as a point-to-point subinterface.
interface serial 0encapsulation frame-relayinterface serial 0.1 multipointip address 131.108.10.1 255.255.255.0frame-relay interface-dlci 42 broadcastframe-relay interface-dlci 53 broadcastinterface serial 0.2 point-to-pointip address 131.108.11.1 255.255.0frame-relay interface-dlci 59 broadcastThe following example configures circuit 0 of a T1 link for Point-to-Point Protocol (PPP) encapsulation:
controller t1 4/1circuit 0 1interface serial 4/1:0ip address 131.108.13.1 255.255.255.0encapsulation pppThe following example configures LAN Extender interface 0:
interface lex 0Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
circuit
controller
mac-address †
ppp †
show interfaces
slip †interface dialer
To designate a dialer rotary group leader, use the interface dialer global configuration command.
interface dialer interface-number
Syntax Description
Default
None
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Dialer rotary groups allow you to apply a single interface configuration to a set of interfaces. Once the interface configuration is propagated to a set of interfaces, those interfaces can be used to place calls using the standard dial-on-demand criteria. When many destinations are configured, any of these interfaces can be used for outgoing calls.
Dialer rotary groups are useful in environments that require many calling destinations. Only the rotary group needs to be configured with all of the dialer map commands. The only configuration required for the interfaces is the dialer rotary-group command that indicates which interface is part of a dialer rotary group.
Although a dialer rotary group is configured as an interface, it is not a physical interface. Instead it represents a group of interfaces. Any number of dialer groups can be defined.
Interface configuration commands entered after the interface dialer command will be applied to all physical interfaces assigned to specified rotary group.
Example
The following example identifies dialer interface 1 as the dialer rotary group leader. Dialer interface 1 is not a physical interface, but represents a group of interfaces. The interface configuration commands that follow apply to all interfaces included in this group.
interface dialer 1encapsulation pppdialer in-banddialer map ip 172.30.2.5 username YYY 14155553434dialer map ip 172.30.4.5 username ZZZRelated Command
A dagger (†) indicates that the command is documented outside this chapter.
dialer rotary-group †
interface fastethernet
To select a particular Fast Ethernet interface for configuration, use the interface fastethernet global configuration command.
interface fastethernet number (Cisco 4500 series and Cisco 4700 series)
interface fastethernet slot/port (Cisco 7000 series and Cisco 7200 series)
interface fastethernet slot/port-adapter/port (Cisco 7500 series)Syntax Description
Default
None
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Examples
The following example configures Fast Ethernet interface 0 for standard Advanced Research Projects Agency (ARPA) encapsulation (the default setting) on a Cisco 4500 or Cisco 4700 router:
interface fastethernet 0Related Command
show interfaces fastethernet
interface group-async
To create a group interface that will serve as master, to which asynchronous interfaces can be associated as members, use the interface group-async command. Use the no form of the command to restore the default.
interface group-async number
no interface group-async numberSyntax Description
Default
No interfaces are designated as group masters.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Using the interface group-async command, you create a single asynchronous interface to which other interfaces are associated as members using the group-range command. This one-to-many configuration allows you to configure all associated member interfaces by entering one command on the group master interface, rather than entering this command on each individual interface. You can create multiple group masters on a device; however, each member interface can only be associated with one group.
Examples
The following example defines asynchronous group master interface 0:
interface group-async 0Related Commands
group-range
memberinvert-transmit-clock
Delays between the SCTE clock and data transmission indicate that the transmit clock signal might not be appropriate for the interface rate and length of cable being used. Different ends of the wire may have variances that differ slightly. To invert the clock signal to compensate for these factors, use the invert-transmit-clock interface configuration command. This command applies only to the Cisco 7000 series and Cisco 7500 series. To return to the transmit clock signal to its initial state, use the no form of this command.
invert-transmit-clock
no invert-transmit-clockSyntax Description
This command has no arguments or keywords.
Default
Not inverted
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
In the following example, the clock signal on serial interface 3/0 is inverted.
interface serial 3/0invert-transmit-clockip address-pool
To enable an address pooling mechanism used to supply IP addresses to dial-in asynchronous, synchronous, or ISDN point-to-point interfaces, use the ip address-pool global configuration command. To disable IP address pooling globally on all interfaces with the default configuration, use the no form of the command.
ip address-pool [dhcp-proxy-client | local]
no ip address-poolSyntax Description
Default
IP address pooling is disabled.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
The global default mechanism applies to all interfaces that have been left in the default setting of the peer default ip address pool command.
If any peer default ip address command other than peer default ip address pool (the default) is configured, then the interface uses that mechanism and not the global default mechanism. Thus all interfaces can be independently configured or left unconfigured so that the global default mechanism setting apply. This flexibility minimizes the configuration effort on the part of the administrator.
Examples
The following example specifies the DHCP proxy client mechanism as the global default mechanism for assigning peer IP addresses:
ip address-pool dhcp-proxy-clientThe following example specifies a local IP address pool called default as the global default mechanism for all interfaces that have been left in their default setting:
ip address-pool localRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
encapsulation ppp †
encapsulation slip †
ip dhcp-server
ip local pool
member peer default ip address
peer default ip address
peer default ip address pool
ppp †
show dhcp
show ip local pool
slip †ip dhcp-server
To specify which Dynamic Host Configuration Protocol (DHCP) servers to use on your network, specify the IP address of one or more DHCP servers available on the network, use the ip dhcp-server global configuration command. Use the no form of the command to remove a DHCP server's IP address.
ip dhcp-server [ip-address | name]
no ip dhcp-server [ip-address | name]Syntax Description
Default
The IP limited broadcast address of 255.255.255.255 is used for transactions if no DHCP server is specified. This allows automatic detection of DHCP servers.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
A DHCP server temporarily allocates network addresses to clients through the access server on an as-needed basis. While the client is active, the address is automatically renewed in a minimum of 20-minute increments. When the user terminates the session, the interface connection is terminated so that network resources can be quickly reused. You can specify up to ten servers on the network.
In normal situations, if a user's SLIP/PPP session fails (for example if a modem line disconnects), the allocated address will be reserved temporarily to preserve the same IP address for the client when dialed back into the server. This way, the session that was accidentally terminated can often be resumed.
To use the DHCP proxy-client feature, enable your access server to be a proxy-client on asynchronous interfaces by using the ip address-pool dhcp-proxy-client command. If you wish to specify which DHCP servers are used on your network, use the ip dhcp-server command to define up to ten specific DHCP servers.
Note
The ip address-pool dhcp-proxy-client command initializes proxy-client status to all interfaces defined as asynchronous on the access server. To selectively disable proxy-client status on a single asynchronous interface, use the no peer default ip address interface command.
Note
Example
The following command specifies a DHCP server with the IP address of 129.12.13.81:
ip dhcp-server 129.12.13.81Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
ip address-pool dhcp-proxy-client
ip helper address †
peer default ip address pool
show dhcp †ip local pool
To configure a local pool of IP addresses to be used when a remote peer connects to a point-to-point interface, use the ip local pool global configuration command. To delete an address pool, use the no form of this command.
ip local pool {default | pool-name low-ip-address [high-ip-address]}
no ip local pool {default | poolname}Syntax Description
Default
No address pools are configured.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Use the ip local pool command to create one or more local address pools from which IP addresses are assigned when a peer connects. The default address pool is then used on all point-to-point interfaces after the ip address-pool local global configuration command is issued. To use a specific, named address pool on an interface, use the peer default ip address pool interface configuration command.
These pools can also be used with the translate command for one-step vty-async connections and in certain AAA/TACACS+ authorization functions. Refer to the "Protocol Translation" chapter in the Access Services Configuration Guide and the "System Management" chapter of the Configuration Fundamentals Configuration Guide for more information. Pools can be displayed with the show ip local pool command.
Example
The following command creates a local IP address pool by the name of quark, which contains all local IP addresses from 172.16.23.0 to 172.16.23.255:
ip local pool quark 172.16.23.0 172.16.23.255Related Commands
ip address-pool
show ip local poolisdn incoming-voice modem
To enable incoming ISDN voice calls to access the AS5200 call switch module and integrated modems, use the isdn incoming-voice modem interface configuration command. The no form of this command stops all incoming ISDN analog calls from routing to the modems.
isdn incoming-voice modem
no isdn incoming-voice modemSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Incoming ISDN digital calls are unaffected by this command. ISDN digital calls directly connect to network resources even when the no isdn incoming-voice modem command is configured.
Example
The following example enables incoming and outgoing ISDN calls to route to the modems using the D channel serial interface:
interface serial 0:23isdn incoming-voice modemkeepalive
To set the keepalive timer for a specific interface, use the keepalive interface configuration command. To turn off keepalives entirely, use the no form of this command.
keepalive [seconds]
no keepalive [seconds]Syntax Description
Default
Enabled and set to 10 seconds on most interfaces; disabled on asynchronous interfaces.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Asynchrounous interfaces do not send and do not expect keepalives from the remote end of a point-to-point connection. To enable keepalives on asynchrounous interfaces, use the keepalive command and set a specific interval.
You can configure the keepalive interval, which is the frequency at which the Cisco IOS software sends messages to itself (Ethernet and Token Ring) or to the other end (serial), to ensure a network interface is alive. The interval in previous software versions was 10 seconds; it is now adjustable in 1-second increments down to 1 second. An interface is declared down after three update intervals have passed without receiving a keepalive packet.
Setting the keepalive timer to a low value is very useful for rapidly detecting Ethernet interface failures (transceiver cable disconnecting, cable unterminated, and so on).
A typical serial line failure involves losing Carrier Detect (CD) signal. Because this sort of failure is typically noticed within a few milliseconds, adjusting the keepalive timer for quicker routing recovery is generally not useful.
Note
Example
The following example sets the keepalive interval to 3 seconds:
interface ethernet 0keepalive 3lex burned-in-address
To set the burned-in MAC address for a LAN Extender interface, use the lex burned-in-address interface configuration command. To clear the burned-in MAC address, use the no form of this command.
lex burned-in-address ieee-address
no lex burned-in-addressSyntax Description
Default
No burned-in MAC address is set
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Use this command only on a LAN Extender interface that is not currently active (not bound to a serial interface).
Example
The following example sets the burned-in MAC address on LAN Extender interface 0:
interface serial 4encapsulation pppinterface lex 0lex burned-in-address 0000.0c00.0001ip address 131.108.172.21 255.255.255.0lex input-address-list
To assign an access list that filters on MAC addresses, use the lex input-address-list interface configuration command. To remove an access list from the interface, use the no form of this command.
lex input-address-list access-list-number
no lex input-address-listSyntax Description
access-list-number
Number of the access list you assigned with the access-list global configuration command. It can be a number from 700 to 799.
Default
No access lists are preassigned to a LAN Extender interface.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3 (The no 1ex input-address-list command first appeared in Cisco IOS Release 10.0.)
Use the lex input-address-list command to filter the packets that are allowed to pass from the LAN Extender to the core router. The access list filters packets based on the source MAC address.
The LAN Extender interface does not process MAC-address masks. Therefore, you should omit the mask from the access-list commands.
For LAN Extender interfaces, an implicit permit everything entry is automatically defined at the end of an access list. Note that this default differs from other access lists, which have an implicit deny everything entry at the end of each access list.
Example
The following example applies access list 710 to LAN Extender interface 0. This access list denies all packets from MAC address 0800.0214.2776 and permits all other packets.
access-list 710 deny 0800.0214.2776interface lex 0lex input-address-list 710Related Command
A dagger (†) indicates that the command is documented outside this chapter.
access-list †
lex input-type-list
To assign an access list that filters Ethernet packets by type code, use the lex input-type-list interface configuration command. To remove an access list from the interface, use the no form of this command.
lex input-type-list access-list-number
no lex input-type-listSyntax Description
access-list-number
Number of the access list you assigned with the access-list global configuration command. It can be a number in the range 200 to 299.
Default
No access lists are preassigned to a LAN Extender interface.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
Filtering is done on the LAN Extender chassis.
The LAN Extender interface does not process masks. Therefore, you should omit the mask from the access-list commands.
For LAN Extender interfaces, an implicit permit everything entry is automatically defined at the end of an access list. Note that this default differs from other access lists, which have an implicit deny everything entry at the end of each access list.
Example
The following example applies access list 220 to LAN Extender interface 0. This access list denies all AppleTalk packets (packets with a type field of 0x809B) and permits all other packets.
access-list 220 deny 0x809B 0x0000interface lex 0lex input-type-list 220Related Command
A dagger (†) indicates that the command is documented outside this chapter.
access-list †
lex priority-group
To activate priority output queuing on the LAN Extender, use the lex priority-group interface configuration command. To disable priority output queuing, use the no form of this command.
lex priority-group group
no lex priority-groupSyntax Description
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
To define queuing priorities, use the priority-list protocol global configuration command. Note that you can use only the following forms of this command:
priority-list list protocol protocol {high | medium | normal | low}
priority-list list protocol bridge {high | medium | normal | low} list list-number
If you specify a protocol that does not have an assigned Ethernet type code, such as x25, stun, or pad, it is ignored and will not participate in priority output queuing.
Example
The following example activates priority output queuing on LAN Extender interface 0:
priority-list 5 protocol bridge medium list 701lex interface 0lex priority-group 5Related Command
A dagger (†) indicates that the command is documented outside this chapter
priority-list protocol †
lex retry-count
To define the number of times to resend commands to the LAN Extender chassis, use the lex retry-count interface configuration command. To return to the default value, use the no form of this command.
lex retry-count number
no lex retry-count [number]Syntax Description
number
Number of times to retry sending commands to the LAN Extender. It can be a number in the range 0 to 100. The default is 10 times.
Default
10
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
After the core router has sent a command the specified number of times without receiving an acknowledgment from the LAN Extender, it stops sending the command altogether.
Example
The following example resends commands 20 times to the LAN Extender:
lex interface 0lex retry-count 20Related Command
lex timeout
lex timeout
To define the amount of time to wait for a response from the LAN Extender, use the lex timeout interface configuration command. To return to the default time, use the no form of this command.
lex timeout milliseconds
no lex timeout [milliseconds]Syntax Description
milliseconds
Time, in milliseconds, to wait for a response from the LAN Extender before resending the command. It can be a number in the range 500 to 60000. The default is 2000 ms (2 seconds).
Default
2000 ms (2 seconds)
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
The lex timeout command defines the amount of time that the core router will wait to receive an acknowledgment after having sent a command to the LAN Extender.
Example
The following example causes unacknowledged packets to be resent at 4-second intervals:
lex interface 0lex timeout 4000Related Command
lex retry-count
linecode
Use the linecode controller configuration command to select the line-code type for the T1 or E1 line.
linecode {ami | b8zs | hdb3}
Syntax Description
Defaults
AMI is the default for T1 lines.
High-density bipolar 3 is the default for E1 lines.
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0. (The option hdb3 first appeared in Cisco IOS Release 10.3.)
Use this command in configurations where the router or access server must communicate with T1 fractional data lines. The T1 service provider determines which line-code type, either ami or b8zs, is required for your T1 circuit. Likewise, the E1 service provider determines which line-code type, either ami or hdb3, is required for your E1 circuit.
Example
The following example specifies B8ZS as the line-code type:
linecode b8zslink-test
To reenable the link-test function on a port on an Ethernet hub of a Cisco 2505 or Cisco 2507, use the link-test hub configuration command. Use the no form of this command to disable this feature if a pre-10BaseT twisted-pair device not implementing link test is connected to the hub port.
link-test
no link-testSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Hub configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
This command applies to a port on an Ethernet hub only. Disable this feature if a 10BaseT twisted-pair device at the other end of the hub does not implement the link test function.
Example
The following example disables the link test function on hub 0, ports 1 through 3:
hub ethernet 0 1 3no link-testRelated Command
hub
local-lnm
To enable Lanoptics Hub Networking Management of a PCbus Token Ring interface, use the local-lnm interface configuration command. Use the no form of this command to disable Lanoptics Hub Networking Management.
local-lnm
no local-lnmSyntax Description
This command has no arguments or keywords.
Default
Management is not enabled.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
The Token Ring interface on the AccessPro PC card can be managed by a remote LAN manager over the PCbus interface. At present, the Lanoptics Hub Networking Management software running on an IBM compatible PC is supported.
Example
The following example enables Lanoptics Hub Networking Management:
local-lnmloopback (E1 controller)
To loop an entire E1 line (including all channel-groups defined on the controller) toward the line and back toward the router or access server, use the loopback controller configuration command. To remove the loop, use the no form of this command.
loopback
no loopbackSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
This command is useful for testing the DCE device (CSU/DSU) itself.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures the loopback test on the E1 line:
controller e1 0 loopbackloopback (interface)
To diagnose equipment malfunctions between interface and device, use the loopback interface configuration command. The no loopback command disables the test.
loopback
no loopbackSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
On HSSI serial interface cards, the loopback function configures a two-way internal and external loop on the HSA applique of the specific interface.
On MCI and SCI serial interface cards, the loopback functions when a CSU/DSU or equivalent device is attached to the router or access server. The loopback command loops the packets through the CSU/DSU to configure a CSU loop, when the device supports this feature.
On the MCI and MEC Ethernet cards, the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
On the CSC-FCI FDDI card, the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
On all Token Ring interface cards (except the 4-megabit CSC-R card), the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
Note
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures the loopback test on Ethernet interface 4:
interface ethernet 4 loopbackRelated Commands
down-when-looped
show interfaces loopbackloopback applique
To configure an internal loop on the HSSI applique, use the loopback interface configuration command. To remove the loop, use the no form of this command.
loopback applique
no loopback appliqueSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command loops the packets within the applique, to provide a way to test communication within the router or access server. It is useful for sending pings to yourself to check functionality of the applique.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures the loopback test on the HSSI applique:
interface serial 1 loopback appliqueRelated Command
show interfaces loopback
loopback dte
To loop packets back to the DTE from the CSU/DSU, when the device supports this feature, use the loopback interface configuration command. To remove the loop, use the no form of this command.
loopback dte
no loopback dteSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command is useful for testing the DTE-to-DCE cable.
For the Cisco 2524 and Cisco 2525 routers, this command is used to test the performance of the integrated CSU/DSU. Packets are looped from within the CSU/DSU back to the serial interface of the router. Send a test ping to see if the packets successfully looped back. To cancel the loopback test, use the no loopback dte command.
When using the 4-wire 56/64-kbps CSU/DSU module, an out-of-service signal is transmitted to the remote CSU/DSU.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures the loopback test on the DTE interface:
interface serial 1 loopback dteRelated Command
show interfaces loopback
loopback line
To loop packets completely through the CSU/DSU to configure the CSU loop, when the device supports this feature, use the loopback line interface configuration command. To remove the loop, use the no form of this command.
loopback line [payload]
no loopback line [payload]Syntax Description
payload
(Optional) Configures a loopback point at the DSU and loops back data to the network on an integrated CSU/DSU for a Cisco 2524 and Cisco 2525.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command is useful for testing the DCE device (CSU/DSU) itself. When the loopback line command is configured on the 2-wire 56-kbps CSU/DSU module or the 4-wire 56/64-kbps CSU/DSU modules installed on a Cisco 2524 or Cisco 2525 router, the network data loops back at the CSU and the router data loops back at the DSU. If the CSU/DSU is configured for switched mode, you must have an established connection to perform a payload-line loopback. To loop the received data through the minimum amount of CSU/DSU circuitry, issue the loopback line command.
When you issue the loopback line payload command on an integrated CSU/DSU module, the router cannot transmit data through the serial interface for the duration of the loopback. Choosing the DSU as a loopback point loops the received-network data through the maximum amount of CSU/DSU circuitry. Data is not looped back to the serial interface. An active connection is required when operating in switched mode for payload loopbacks.
If you enable the loopback line command on the fractional T1/T1 module, the CSU/DSU performs a full-bandwidth loopback through the CSU portion of the module and data transmission through the serial interface is interrupted for the duration of the loopback. No reframing or corrections of bipolar violation errors or cyclic redundancy check (CRC) errors are performed. When you configure the loopback line payload command on the FT1/T1 module, the CSU/DSU performs a loopback through the DSU portion of the module. The loopback line payload command reframes the data link, regenerates the signal, and corrects bipolar violations and Extended Super Frame CRC errors.
When performing a T1-line loopback with Extended Super Frame on a Cisco 2524 or Cisco 2525 router, communication over the facilities data link is interrupted, but performance statistics are still updated. To show interfaces currently in loopback operation on a Cisco 2524 or Cisco 2525 router, use the show service-module EXEC command.
To show interfaces currently in loopback operation on other routers, use the show interfaces loopback EXEC command.
Example
The following example configures the loopback test on the DCE device:
interface serial 1 loopback lineThe following example shows how to configure a payload loopback on a Cisco 2524 or 2525 router:
Router1(config-if)#loopback line payloadLoopback in progressRouter1(config-if)#no loopback lineThe following example shows the output on a Cisco 2524 or 2525 router when you loop a packet in switched mode without an active connection:
Router1(config-if)#service-module 56k network-type switchedRouter1(config-if)#loopback line payloadNeed active connection for this type of loopback% Service module configuration command failed: WRONG FORMAT.Related Command
show interfaces loopback
loopback local (T1 controller)
To loop an entire T1 line (including all channel-groups defined on the controller) toward the line and the router or access server, use the loopback local controller configuration command. To remove the loop, use the no form of this command.
loopback local
no loopback localSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command is useful for testing the DCE device (CSU/DSU) itself.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures the loopback test on the T1 line:
controller t1 0 loopback localloopback local (interface)
To loop a channelized T1 or channelized E1 channel-group, use the loopback local interface configuration command. To remove the loop, use the no form of this command.
loopback local
no loopback localSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.0.
This command is useful for looping a single channel-group in a channelized environment without disrupting the other channel-groups.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures the loopback test on the T1 line:
interface serial 1/0:22 loopback localRelated Command
show interfaces loopback
loopback remote (T1 controller)
To loop packets from a MIP through the CSU/DSU, over a dedicated T1 link, to the remote CSU at the single destination for this T1 link and back, use the loopback remote controller configuration command. To remove the loop, use the no form of this command.
loopback remote
no loopback remoteSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Controller configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command applies only when the device supports the remote function. It is used for testing the data communication channels.
For MIP cards, this controller configuration command applies if only one destination exists at the remote end of the cloud, the entire T1 line is dedicated to it, and the device at the remote end is a CSU (not a CSU/DSU). This is an uncommon case; MIPs are not usually used in this way.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures a remote loopback test:
interface serial 0 loopback remoteRelated Command
show interfaces loopback
loopback remote (interface)
To loop packets through a CSU/DSU, over a DS-3 link or a channelized T1 link, to the remote CSU/DSU and back, use the loopback remote interface configuration command. To remove the loop, use the no form of this command.
loopback remote
no loopback remoteloopback remote {full | payload | smart-jack} [0in1 | 1in1 | 1in2 | 1in5 | 1in8 | 3in24 | qrw | user-pattern value] (Cisco 2524 or Cisco 2525 only)
no loopback remote {full | payload | smart-jack}loopback remote [2047 | 511 | stress-pattern pattern number] (Cisco 2524 or Cisco 2525 only)
no loopback remote
Note
Syntax Description for the FT1/T1 CSU/DSU
Module
Syntax Description for the 2- and 4-Wire 56/64-kbps CSU/DSU Modules
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command applies only when the remote CSU/DSU device supports the function. It is used for testing the data communication channels. The loopback usually is performed at the line port, rather than the DTE port, of the remote CSU/DSU.
For a multiport interface processor (MIP) connected to a network via a channelized T1 link, the loopback remote interface configuration command applies if the remote interface is served by a DDS line (56 kbps or 64 kbps) and the device at the remote end is a CSU/DSU. In addition, the CSU/DSU at the remote end must react to latched DDS CSU loopback codes. Destinations that are served by other types of lines or that have CSU/DSUs that do not react to latched DDS CSU codes cannot participate in an interface remote loopback. Latched DDS CSU loopback code requirements are described in AT&T specification TR-TSY-000476, "OTGR Network Maintenance Access and Testing."
On the integrated FT1/T1 CSU/DSU module installed on a Cisco 2524 and Cisco 2525 router, the loopback remote full command sends the loopup code to the remote CSU/DSU. The remote CSU/DSU performs a full-bandwidth loopback through the CSU portion of the module. The loopback remote payload command sends the loopup code on the configured timeslots, while maintaining the D4-extended super framing. The remote CSU/DSU performs the equivalent of a loopback line payload request. The remote CSU/DSU loops back only those timeslots that are configured at the remote end. This loopback reframes the data link, regenerates the signal, and corrects bipolar violations and Extended Super Frame CRC errors. The loopback remote smart-jack command sends a loopup code to the remote smart jack. You cannot put the local smart jack into loopback.
Failure to loopup or initiate a remote loopback request could be caused by enabling the no service-module t1 remote-loopback command or having an alternate remote-loopback code configured on the remote end. When the loopback is terminated, the result of the pattern test is displayed.
On the 2- and 4-wire 56/64-kbps CSU/DSU modules installed on a Cisco 2524 or Cisco 2525 router, an active connection is required before a loopup can be initiated while in switched mode. When transmitting V.54 loopbacks, the remote device is commanded into loopback using V.54 messages. Failure to loopup or initiate a remote loopback request could be caused by enabling the no service-module 56k remote-loopback command.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Example
The following example configures a remote loopback test:
interface serial 0 loopback remoteRelated Command
show interfaces loopback
media-type
To specify the physical connection for one of the following configurations, use the media type command:
•
•
•
Use the no form of this command to restore the default value.
media-type {aui | 10baset | 100baset | mii}
no media-type {aui | 10baset | 100baset | mii}Syntax Description
aui
Selects a 15-pin physical connection.
10baset
Selects an RJ45 10BaseT physical connection.
100baset
Specifies an RJ45 100BaseT physical connection.
mii
Specifies a media-independent interface.
Default
AUI 15-pin physical connection is the default setting on the Cisco 4000 series.
100BaseT physical connection is the default setting on the Cisco 7000 series and 7200 series.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Examples
The following example selects an RJ45 10BaseT physical connection on Ethernet interface 1:
interface ethernet 1 media-type 10basetThe following example specifies a media-independent interface physical connection to Fast Ethernet slot 0, port 1 on the Cisco 7000 or 7200 series:
interface fastethernet 0/1media-type miiThe following example specifies a media-independent interface physical connection to Fast Ethernet slot 0, port-adapter 1, port 1 on the Cisco 7500 series:
interface fastethernet 0/1/1media-type miimember
To alter the configuration of an asynchronous interface that is a member of a group, use the member interface configuration command. Use the no form of the command to restore defaults set at the group master interface.
member number interface-command
no member number interface-commandSyntax Description
number
Number of the asynchronous interface to be altered.
interface-command
One or more of the following commands entered for this specific interface:
•
•
Default
No individual configurations are set for member interfaces.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
You can customize a member interface by using the member command. (Interfaces are designated as members of a group by using the interface group-async and group-range commands.) To restore the defaults set at the group master interface, use the no form of this command.
Example
The following example defines interface 3 with a description of line 3, attached to a Hayes Optima modem:
interface group-async 0 member 3 description line #3 Hayes OptimaRelated Commands
group-range
interface group-asyncmop enabled
To enable an interface to support the Maintenance Operation Protocol (MOP), use the mop enabled interface configuration command. To disable MOP on an interface, use the no mop enabled command.
mop enabled
no mop enabledSyntax Description
This command has no arguments or keywords.
Default
Enabled on Ethernet interfaces and disabled on all other interfaces.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
In the following example, MOP is enabled for serial interface 0:
interface serial 0mop enabledRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
mop retransmit-timer †
mop retries †
mop sysidmop sysid
To enable an interface to send out periodic Maintenance Operation Protocol (MOP) system identification messages, use the mop sysid interface configuration command. To disable MOP message support on an interface, use the no form of this command.
mop sysid
no mop sysidSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
You can still run MOP without having the background system ID messages sent. This lets you use the MOP remote console, but does not generate messages used by the configurator.
Example
In the following example, serial interface 0 is enabled to send MOP system identification messages:
interface serial 0mop sysidRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
mop device-code †
mop enabledmtu
To adjust the maximum packet size or maximum transmission unit (MTU) size, use the mtu interface configuration command. Use the no form of this command to restore the MTU value to its original default value.
mtu bytes
no mtuSyntax Description
Defaults
lists default MTU values according to media type.
Table 24 Default Media MTU Values
Ethernet
1500
Serial
1500
Token Ring
4464
ATM
4470
FDDI
4470
HSSI (HSA)
4470
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Each interface has a default maximum packet size or maximum transmission unit (MTU) size. This number generally defaults to the largest size possible for that type interface. On serial interfaces, the MTU size varies, but cannot be set smaller than 64 bytes.
CautionChanging an MTU size on a Cisco 7500 router will result in recarving of buffers and resetting of all interfaces. The following message is displayed:
%RSP-3-Restart:cbus complex
Note
Example
The following example specifies an MTU of 1000 bytes:
interface serial 1 mtu 1000Related Commands
A dagger (†) indicates that the command is documented outside this chapter.
encapsulation smds †
ip mtu †nrzi-encoding
To enable non-return to zero inverted (NRZI) line coding format, use the nrzi-encoding interface configuration command. Use the no form of this command to disable this capability.
nrzi-encoding
no nrzi-encodingSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
All FSIP interface types support nonreturn to zero (NRZ) and nonreturn to zero inverted (NRZI) format. This is a line coding format that is required for serial connections in some environments. NRZ encoding is most common. NRZI encoding is used primarily with RS-232 connections in IBM environments.
Example
In the following example, serial interface 1 is configured for NRZI encoding:
interface serial 1nrzi-encodingpeer default ip address
Use the peer default ip address interface configuration command to specify an IP address, an address from a specific IP address pool, or an address from the DHCP mechanism to be returned to a remote peer connecting to this interface. Use the no form of the command to disable a prior peer IP address pooling configuration on an interface.
peer default ip address {ip-address | dhcp | pool [pool-name]}
no peer default ip addressSyntax Description
Default
pool
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.3.
This command applies to point-to-point interfaces that support the PPP or SLIP encapsulation.
This command allows an administrator to configure all possible address pooling mechanisms on a interface-by-interface basis.
The peer default ip address command can override the global default mechanism defined by the ip address-pool command on an interface-by-interface basis.
•
•
•
•
Examples
The following command specifies that this interface will use a local IP address pool called pool3:
peer default ip address pool pool3The following command specifies that this interface will use the IP address 172.140.34.21:
peer default ip address 172.140.34.21The following command reenables the global default mechanism to be used on this interface:
peer default ip address poolRelated Commands
A dagger (†) indicates that the command is documented outside this chapter.
encapsulation ppp
encapsulation slip
ip address-pool
ip dhcp-server
ip local pool
ppp †
slip †
show dhcpphysical-layer
To specify the mode of a slow-speed serial interface on a router as either synchronous or asynchronous, use the physical-layer interface configuration command. Use the no form of this command to return the interface to its default mode, which is synchronous.
physical-layer {sync | async}
no physical-layerSyntax Description
Default
Synchronous mode
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies only to low-speed serial interfaces available on Cisco 2520 through Cisco 2523 routers.
If you specify the no physical-layer command, you return the interface to its default mode (synchronous).
In synchronous mode, low-speed serial interfaces support all interface configuration commands available for high-speed serial interfaces, except the following two commands:
•
•
When placed in asynchronous mode, low-speed serial interfaces support all commands available for standard asynchronous interfaces.
When you enter this command, it does not appear in the output of show running config and show startup config commands, because the command is a physical layer command.
Examples
The following examples show different uses of this command.
The following example shows how to change a low-speed serial interface from synchronous to asynchronous mode:
interface serial 2physical-layer asyncposi framing-sdh
To select SDH STM-1 framing on a Packet OC-3 interface in a Cisco RSP/7000 or Cisco 7500 router, which has a Route Switch Processor, use the posi framing-sdh interface configuration command. To revert to the default SONET STS-3c framing, use the no form of this command.
posi framing-sdh
no posi framing-sdhSyntax Description
This command has no keywords or arguments.
Default
SONET STS-3c framing
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Example
In the following example, the interface is configured for SDH STM-1 framing:
interface posi 3/0posi framing-sdhno shutdownRelated Commands
interface posi
posi internal-clockposi internal-clock
To set the internal clock as the transmission clock source, use the posi internal-clock interface configuration command. To revert to the default recovered receive clock as the transmission clock source, use the no form of this command.
posi internal-clock
no posi internal-clockSyntax Description
This command has no keywords or arguments.
Default
The recovered receive clock
Command mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Example
The following command reverts to the default recovered receive clock:
interface posi 3/0no posi internal-clockRelated Commands
interface posi
posi framing-sdhpulse-time
To enable pulsing DTR signal intervals on the serial interfaces, use the pulse-time interface configuration command. Use the no form of this command to restore the default interval.
pulse-time seconds
no pulse-timeSyntax Description
Default
0 seconds
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
When the serial line protocol goes down (for example, because of loss of synchronization) the interface hardware is reset and the DTR signal is held inactive for at least the specified interval. This function is useful for handling encrypting or other similar devices that use the toggling of the DTR signal to resynchronize.
Example
The following example enables DTR pulse signals for three seconds on serial interface 2:
interface serial 2 pulse-time 3ring-speed
To set the ring speed for the CSC-1R and CSC-2R Token Ring interfaces, use the ring-speed interface configuration command.
ring-speed speed
Syntax Description
Default
16-Mbps operation
CautionConfiguring a ring speed that is wrong or incompatible with the connected Token Ring will cause the ring to beacon, which effectively takes the ring down and makes it nonoperational.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example sets a Token Ring interface ring speed to 4 Mbps:
interface tokenring 0 ring-speed 4service-module 56k clock rate
To configure the network line speed for a 4-wire 56/64-kbps CSU/DSU module, use the service-module 56k clock rate interface configuration command. Use the no form of this command to enable a network line speed of 56 kbps.
service-module 56k clock rate line-speed
no service-module 56k clock rate line-speedSyntax Description
line-speed
Network line speed in kbps; one of the following keywords 2.4, 4.8, 9.6, 19.2, 38.4, 56, 64, and auto. Default is 56 kbps.
Default
56 kbps
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
The 64-kbps line speed cannot be used with back-to-back digital data service (DDS) lines. The subrate line speeds are determined by the service provider.
Only the 56-kbps line speed is available in switched mode, which is enabled using the service-module 56k network-type interface configuration command on the 4-wire CSU/DSU. The 2-wire CSU/DSU default is set to switched mode.
The keyword auto enables the CSU/DSU to decipher current line speed from the sealing current running on the network. Use auto only when transmitting over telco DDS lines and the clocking source is taken from the line.
Example
The following example displays two routers connected in back-to-back DDS mode. However, the configuration fails because the auto rate is used.
Router1(config-if)#service-module 56k clock source internalRouter1(config-if)#service-module 56k clock rate 38.4Router2(config-if)#service-module 56k clock rate autoa1#ping 10.1.1.2Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:.....Success rate is 0 percent (0/5)Router2(config-if)#service-module 56k clock rate 38.4Router1#ping 10.1.1.2Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 52/54/56 msWhen transferring from DDS mode to switched mode, you must set the correct clock rate, as shown in the following example:
Router2(config-if)#service-module 56k network-type ddsRouter2(config-if)#service-module 56k clock rate 38.4Router2(config-if)#service-module 56k network-type switched% Have to use 56k or auto clock rate for switched mode% Service module configuration command failed: WRONG FORMAT.Router2(config-if)#service-module 56k clock rate auto% WARNING - auto rate will not work in back-to-back DDS.Router2(config-if)#service-module 56k network-type switchedRelated Commands
service-module 56k clock source
service-module 56k network-typeservice-module 56k clock source
To configure the clock source for the 4-wire 56/64-kbps CSU/DSU module, use the service-module 56k clock source interface configuration command. Use the no form of this command to enable the line clock.
service-module 56k clock source {line | internal}
no service-module 56k clock source {line | internal}Syntax Description
line
Uses the clocking provided by the active line.
internal
Uses internal clocking provided by the module.
Default
Line clock
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
In most applications, the CSU/DSU should be configured with the clock source line command. For back-to-back configurations, configure one CSU/DSU with the clock source internal command and the other with clock source line command.
Example
The following example configures internal clocking and transmission at 38.4 kbps.
service-module 56k clock source internalservice-module 56k clock rate 38.4Related Command
service-module 56k clock rate
service-module 56k data-coding
To prevent application data from replicating loopback codes when operating at 64 kbps on a 4-wire CSU/DSU, use the service-module 56k data-coding interface configuration command. Use the no form of this command to enable normal transmission.
service-module 56k data-coding {normal | scrambled}
no service-module 56k data-coding {normal | scrambled}Syntax Description
normal
Specifies normal transmission of data.
scrambled
Scrambles bit codes or user data before transmission. All control codes such as out of service and out of frame are avoided.
Default
Normal data transmission
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies only to the Cisco 2524 or Cisco 2525 router.
Enable the scrambled configuration only in 64-kbps digital data service (DDS) mode. If the network type is set to switched, the configuration is refused.
If you transmit scrambled bit codes, both CSU/DSUs must have this command configured for successful communication.
Example
The following example scrambles bit codes or user data before transmission:
service-module 56k clock rate 64service-module 56k data-coding scrambledRelated Command
service-module 56k clock rate
service-module 56k network-type
To transmit packets in switched dial-up mode or digital data service (DDS) mode using the 4-wire 56/64-kbps CSU/DSU module, use the service-module 56k network-type interface configuration command. Use the no form of this command to transmit from a dedicated leased line in DDS mode.
service-module 56k network-type {dds | switched}
no service-module 56k network-type {dds | switched}Syntax Description
dds
Transmits packets in DDS mode or through a dedicated leased line.
switched
Transmits packets in switched dial-up mode, which is the only setting on the 2-wire switched 56-kbps CSU/DSU module.
Default
DDS is enabled for the 4-wire CSU/DSU.
Switched is enabled for the 2-wire CSU/DSU.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies to the Cisco 2524 and Cisco 2525 routers.
In switched mode, you need additional dialer configuration commands to configure dial-out numbers. Before you enable the service-module 56k network-type switched command, both CSU/DSUs must use a clock source coming from the line and the clock rate configured to auto or 56 kbps. If the clock rate is not set correctly, this command will not be accepted.
The 2-wire and 4-wire 56/64-kbps CSU/DSU modules use V.25 bis dial commands to interface with the router. Therefore, the interface must be configured using the dialer in-band command. DTR dial is not supported.
Note
Example
The following example configures transmission in switched dial-up mode:
service-module 56k clock rate autoservice-module 56k network-type switcheddialer in-banddialer string 2576666dialer-group 1Related Commands
A dagger (†) indicates that the command is documented in another chapter.
dialer in-band †
service-module 56k clock rate
service-module 56k clock source
service-module 56k switched-carrierservice-module 56k remote-loopback
To enable the acceptance of a remote loopback request on a 2- or 4-wire 56/64-kbps CSU/DSU module, use the service-module 56k remote-loopback interface configuration command. Use the no form of this command to disable the module from entering loopback.
service-module 56k remote-loopback
no service-module 56k remote-loopbackSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies to the Cisco 2524 and Cisco 2525 routers.
The no service-module 56k remote-loopback command prevents the local CSU/DSU from being placed into loopback by remote devices on the line. The line provider is still able to put the module into loopback by reversing sealing current. Unlike the T1 module, the 2- or 4-wire 56/64-kbps CSU/DSU module can still initiate remote loopbacks with the no form of this command configured.
Examples
The following example enables transmitting and receiving remote loopbacks:
service-module 56k remote-loopbackRelated Command
loopback remote (interface)
service-module 56k switched-carrier
To select a service provider to use with a 2- or 4-wire 56/64 kbps dial-up line, use the service-module 56k switched-carrier interface configuration command. Use the no form of this command to enable the default service provider.
service-module 56k switched-carrier {att | sprint | other}
no service-module 56k switched-carrier {att | sprint | other}Syntax Description
att
AT&T or other digital network service provider.
sprint
Sprint or other service provider whose network requires echo cancelers.
other
Service provider besides AT&T or Sprint.
Default
ATT is enabled on the 4-wire 56/64-kbps CSU/DSU module.
Sprint is enabled on the 2-wire switched 56-kbps CSU/DSU module.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Use this command only on the 2- or 4-wire 56/64-kbps CSU/DSU modules installed on a Cisco 2524 or Cisco 2525 router.
On a Sprint network, echo-canceler tones are sent during call setup to prevent the echo cancelers from damaging digital data. The transmission of echo-canceler tones may increase call setup times by 8 seconds on the 4-wire module. Having echo cancellation enabled does not affect data traffic.
This configuration command is ignored if the network type is DDS.
Example
The following example configures AT&T as a service provider:
service-module 56k network-type switchedservice-module 56k switched-carrier attRelated Command
service-module 56k network-type
service-module t1 clock source
To specify the clock source for the fractional T1/T1 CSU/DSU module installed in a Cisco 2524 or Cisco 2525 router, use the service-module t1 clock source interface configuration command. Use the no form of this command to enable the line clock.
service-module t1 clock source {internal | line}
no service-module t1 clock source {internal | line}Syntax Description
Default
Line clock
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Example
The following example sets an internal clock source on serial line 0:
interface serial 0service-module t1 clock source lineRelated Command
service-module 56k clock source
service-module t1 data-coding
To guarantee the ones density requirement on an AMI line using the fractional T1/T1 module, use the service-module t1 data-coding inverted interface configuration command. Use the no form of this command to enable normal data transmission.
service-module t1 data-coding {inverted | normal}
no service-module t1 data-coding {inverted | normal}Syntax Description
inverted
Inverts bit codes by changing all 1 bits into 0 bits and all 0 bits into 1 bits.
normal
Requests that no bit codes be inverted before transmission.
Default
Normal transmission
Command Mode
Interface configuration
Usage Guidelines
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies to the Cisco 2524 and Cisco 2525 routers.
Data inversion is used to guarantee the ones density requirement on an AMI line when using bit-oriented protocols such as High-Level Data Link Control (HDLC), Point-to-Point Protocol (PPP), X.25, and Frame Relay. If the timeslot speed is set to 56 kbps, this command is rejected because line density is guaranteed when transmitting at 56 kbps. Use this command with the 64-kbps line speed.
If you transmit inverted bit codes, both CSU/DSUs must have this command configured for successful communication.
Example
The following example inverts bit codes using a timeslot speed of 64 kbps:
service-module t1 timeslots all speed 64service-module t1 data-coding invertedRelated Commands
service-module t1 linecode
service-module t1 timeslotsservice-module t1 framing
To select the frame type for a line using the fractional T1/T1 (FT1/T1) module from a Cisco 2524 or Cisco 2525 router, use the service-module t1 framing interface configuration command. Use the no form of this command to select the default, which is Extended Super Frame as the T1 frame type.
service-module t1 framing {esf | sf}
no service-module t1 framing {esf | sf}Syntax Description
esf
Specifies Extended Super Frame as the T1 frame type.
sf
Specifies D4 Super Frame as the T1 frame type.
Default
esf
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Use this command in configurations where the router communicates with FT1/T1 data lines. The service provider determines which framing type, either esf or sf, is required for your circuit.
Example
The following example enables Super Frame as the FT1/T1 frame type:
service-module t1 framing sfservice-module t1 lbo
To configure the CSU line build out (LBO) on a fractional T1/T1 CSU/DSU module, use the service-module t1 lbo interface configuration command. Use the no form of this command to disable line build out.
service-module t1 lbo {-15 db | -7.5 db | none}
no service-module t1 lbo {-15 db | -7.5 db | none}Syntax Description
-15 db
Decreases outgoing signal strength by 15 dB.
-7.5 db
Decreases outgoing signal strength by 7.5 dB.
none
Transmits packets without decreasing outgoing signal strength.
Default
No line build out
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies to the Cisco 2524 and Cisco 2525 routers.
Use this command to decrease the outgoing signal strength to an optimum value for a fractional T1 line receiver. The ideal signal strength should be -15 dB to -22 dB, which is calculated by adding the phone company loss + cable length loss + line build out.
You may use this command in back-to-back configurations, but it is not needed on most actual T1 lines.
Example
The following example shows an lbo setting of -7.5 dB:
service-module t1 lbo -7.5dbservice-module t1 linecode
To select the line code for the fractional T1/T1 module installed on a Cisco 2524 or Cisco 2525 router, use the service-module t1 linecode interface configuration command. Use the no form of this command to select the default, which is the B8ZS line code.
service-module t1 linecode {ami | b8zs}
no service-module t1 linecode {ami | b8zs}Syntax Description
ami
Specifies alternate mark inversion (AMI) as the line code.
b8zs
Specifies binary 8 zero substitution (B8ZS) as the line code.
Default
b8zs
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Configuring B8ZS is a method of ensuring the ones density requirement on a T1 line by substituting intentional bipolar violations in bit positions four and seven for a sequence of eight zero bits. When the CSU/DSU is configured for AMI, you must guarantee the ones density requirement in your router configuration using the service-module t1 data-coding inverted command or the service-module t1 timeslots speed 56 command.
Your T1 service provider determines which line code, either ami or b8zs, is required for your T1 circuit.
Example
The following example specifies AMI as the line code:
service-module t1 linecode amiRelated Commands
service-module t1 data-coding
service-module t1 timeslotsservice-module t1 remote-alarm-enable
To generate remote alarms (yellow alarms) at the local CSU/DSU or detect remote alarms sent from the remote CSU/DSU, use the service-module t1 remote-alarm-enable interface configuration command. Use the no form of this command to disable remote alarms.
service-module t1 remote-alarm-enable
no service-module t1 remote-alarm-enableSyntax Description
This command has no arguments or keywords.
Default
Remote alarms disabled
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies to the fractional T1/T1 CSU/DSU module installed on Cisco 2524 and Cisco 2525 routers.
Remote alarms are transmitted by the CSU/DSU when it detects an alarm condition, such as a red alarm (loss of frame) or blue alarm (unframed ones). The receiving CSU/DSU then knows there is an error condition on the line.
With D4 Super Frame configured, a remote alarm condition is transmitted by setting the bit 2 of each time slot to zero. For received user data that has the bit 2 of each time slot set to zero, the CSU/DSU interprets the data as a remote alarm and interrupts data transmission, which explains why remote alarms are disabled by default. With Extended Super Frame configured, the remote alarm condition is signalled out of band in the facilities data link.
You can see if the FT1/T1 CSU/DSU is receiving a remote alarm (yellow alarm) by issuing the show service-module command.
Example
The following example enables remote alarm generation and detection:
service-module t1 remote-alarm-enableRelated Command
service-module t1 framing
service-module t1 remote-loopback
To specify if the fractional T1/T1 CSU/DSU module enters loopback mode when it receives a loopback code on the line, use the service-module t1 remote-loopback interface configuration command. Use the no form of this command to disable remote loopbacks.
service-module t1 remote-loopback {full | payload} [alternate | v54]
no service-module t1 remote-loopback {full | payload}Syntax Description
Note
Default
Full and payload loopbacks with standard-loopup codes
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command applies only to the Cisco 2524 and Cisco 2525 routers.
You can simultaneously configure the full and payload loopback points. However, only one loopback code can be configured at a time. For example, if you configure the service-module t1 remote-loopback payload alternate command, a payload v54 request cannot be transmitted or accepted.
The no form of this command disables loopback requests. For example, the no service-module t1 remote-loopback full command ignores all full-bandwidth loopback transmissions and requests. Configuring the no form of the command may not prevent telco line providers from looping your router in esf mode, because fractional T1/T1 lines use facilities data link messages to initiate loopbacks.
If you enable the service-module t1 remote-loopback command, the loopback remote commands on the FT1/T1 CSU/DSU module will not be successful.
Example
The following example displays two routers connected back-to-back through a fractional T1/T1 line:
no service-module t1 remote-loopback fullservice-module t1 remote-loopback payload alternateloopback remote full%SERVICE_MODULE-5-LOOPUPFAILED: Unit 0 - Loopup of remote unit failedservice-module t1 remote-loopback payload v54loopback remote payload%SERVICE_MODULE-5-LOOPUPFAILED: Unit 0 - Loopup of remote unit failedservice-module t1 remote-loopback payload alternateloopback remote payload%SERVICE_MODULE-5-LOOPUPREMOTE: Unit 0 - Remote unit placed in loopbackRelated Command
loopback remote (interface)
service-module t1 timeslots
To define timeslots that constitute a fractional T1/T1 (FT1/T1) channel in a Cisco 2524 or Cisco 2525 router, use the service-module t1 timeslots interface configuration command. Use the no form of this command to resume the default setting (all FT1/T1 timeslots transmit at 64 kbps).
service-module t1 timeslots {range | all} [speed {56 | 64}]
no service-module t1 timeslots {range | all}Syntax Description
Default
64 kbps
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
This command specifies which timeslots are used in fractional T1 operation and determines the amount of bandwidth available to the router in each FT1/T1 channel.
The timeslot range must match the timeslots assigned to the channel group. Your service provider defines the timeslots that comprise a channel group.
To use the entire T1 line, enable the service-module t1 timeslots all command.
Example
The following example displays a series of timeslot ranges and a speed of 64 kbps:
service-module t1 timeslots 1-10,15-20,22 speed 64Related Commands
service-module t1 data-coding
service-module t1 linecodeshow async status
To display the status of the asynchronous interfaces (which on routers is interface 1, the auxiliary port), use the show async status user EXEC command:
show async status
Syntax Description
This command has no arguments or keywords.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Shows all asynchronous sessions, whether they are using SLIP or PPP encapsulation.
Sample Display
The following is sample output from the show async status command:
Router> show async statusAsync protocol statistics:Rcvd: 5448 packets, 7682760 bytes1 format errors, 0 checksum errors, 0 overrun, 0 no bufferSent: 5455 packets, 7682676 bytes, 0 droppedInt Local Remote Qd InPack OutPac Inerr Drops MTU Qsz1 192.31.7.84 Dynamic 0 0 0 0 0 1500 10describes significant fields shown in the display.
Related Commands
async default ip address
async dynamic address
async dynamic routing
async mode dedicated
async mode interactive
interface asyncshow compress
To display compression statistics, use the show compress EXEC command.
show compress
Syntax Description
This command has no arguments or parameters.
Command Mode
EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Sample Display
The following is sample output from the show compress command:
Router# show compressSerial0uncompressed bytes xmt/rcv 10710562/113768351 min avg ratio xmt/rcv 2.773/2.4745 min avg ratio xmt/rcv 4.084/3.79310 min avg ratio xmt/rcv 4.125/3.873no bufs xmt 0 no bufs rcv 0resets 0describes the fields shown in the display.
Related Command
compress
show controllers async
Use the show controllers async EXEC command to display information about interface hardware, registers, and random access memory on the Cisco 1005 router.
show controllers async number
Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 11.2.
Sample Display
The following is sample output from the show controllers async command:
1005# show controllers async 1QUICC Async unit 1, idb at 0x22A3950, driver data structure at 0x22A7F78SCC Registers:General [GSMR]=0x62:0x00028034, Protocol-specific [PSMR]=0x7000Events [SCCE]=0x0000, Mask [SCCM]=0x022F, Status [SCCS]=0x0003Transmit on Demand [TODR]=0x0, Data Sync [DSR]=0x7E7EInterrupt Registers:Config [CICR]=0x00368460, Pending [CIPR]=0x8500C804Mask [CIMR]=0x48000012, In-srv [CISR]=0x00000000Command register [CR]=0x6C0Port A [PADIR]=0x0008, [PAPAR]=0x5AC3[PAODR]=0x0000, [PADAT]=0xB8EAPort B [PBDIR]=0x020F1F, [PBPAR]=0x0000C0[PBODR]=0x000000, [PBDAT]=0x000EC0Port C [PCDIR]=0x0384, [PCPAR]=0x0009[PCSO]=0x0030, [PCDAT]=0x0300, [PCINT]=0x0000DTE V.24 (RS-232) serial cable attached.SCC GENERAL PARAMETER RAM (at 0xFF00F00)Rx BD Base [RBASE]=0x560, Fn Code [RFCR]=0x18Tx BD Base [TBASE]=0x5E0, Fn Code [TFCR]=0x18Max Rx Buff Len [MRBLR]=1500Rx State [RSTATE]=0x18001000, BD Ptr [RBPTR]=0x5A8--More--Tx State [TSTATE]=0x0, BD Ptr [TBPTR]=0x5E0SCC UART PARAMETER RAM (at 0xFF00F00)Maximum idle characters 5Break Character 1Received Parity Error 0Received Frame Error 0Received Noise Error 0Number of break conditions 0Break length 0uart1 0uart2 0Out of sequence 0cc[0] = 8000cc[1] = 8000cc[2] = 8000cc[3] = 8000cc[4] = 8000cc[5] = 8000cc[6] = 8000cc[7] = 8000rccm = C0FFrccr = 0rlbc = 0RX ring with 16 entries at 0xFF00560, Buffer size 1500Rxhead = 0xFF005A8 (9), Rxp = 0x22A7FB8 (9)00 pak=0x22AA3E8 buf=0x23B3440 status=9000 pak_size=001 pak=0x22AA23C buf=0x23B2DA0 status=9000 pak_size=002 pak=0x22AAA98 buf=0x23B4EC0 status=9000 pak_size=003 pak=0x22AAC44 buf=0x23B5560 status=9000 pak_size=004 pak=0x22AA8EC buf=0x23B4820 status=9000 pak_size=005 pak=0x22AA594 buf=0x23B3AE0 status=9000 pak_size=006 pak=0x22AA740 buf=0x23B4180 status=9000 pak_size=007 pak=0x22AA090 buf=0x23B2700 status=9000 pak_size=008 pak=0x22A9EE4 buf=0x23B2060 status=9000 pak_size=009 pak=0x22A99E0 buf=0x23B0C80 status=9000 pak_size=010 pak=0x22A9834 buf=0x23B05E0 status=9000 pak_size=011 pak=0x22A9688 buf=0x23AFF40 status=9000 pak_size=012 pak=0x22A94DC buf=0x23AF8A0 status=9000 pak_size=013 pak=0x22A9330 buf=0x23AF200 status=9000 pak_size=014 pak=0x22A9184 buf=0x23AEB60 status=9000 pak_size=015 pak=0x22A8FD8 buf=0x23AE4C0 status=B000 pak_size=0TX ring with 2 entries at 0xFF005E0, tx_count = 0tx_head = 0xFF005E0 (0), head_txp = 0x22A7FF0 (0)tx_tail = 0xFF005E0 (0), tail_txp = 0x22A7FF0 (0)00 pak=0x0000000 buf=0x0000000 status=0000 pak_size=001 pak=0x0000000 buf=0x0000000 status=2000 pak_size=0QUICC SCC specific errors:0 input aborts on receiving flag sequence0 throttles, 0 enables0 overruns0 transmitter underruns0 transmitter CTS lostsshow controllers cbus
To display all information under the cBus controller card, use the show controllers cbus privileged EXEC command on the Cisco 7000, Cisco RSP/7000, Cisco 7500, or Cisco 7513 routers. This command also shows the capabilities of the card and reports controller-related failures.
show controllers cbus
Syntax Description
This command has no arguments or keywords.
Command Mode
Privileged EXEC
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Sample Displays
The following is partial sample output from the show controllers cbus command on a Cisco 7500 series router with one VIP2 interface processor. This example does not show output from additional interface processors that are usually installed in a Cisco 7500 series router.
Router# show controller cbusMEMD at 40000000, 2097152 bytes (unused 2752, recarves 1, lost 0)RawQ 48000100, ReturnQ 48000108, EventQ 48000110BufhdrQ 48000138 (2849 items), LovltrQ 48000150 (42 items, 1632 bytes)IpcbufQ 48000158 (32 items, 4096 bytes)3570 buffer headers (48002000 - 4800FF10)pool0: 15 buffers, 256 bytes, queue 48000140pool1: 368 buffers, 1536 bytes, queue 48000148pool2: 260 buffers, 4544 bytes, queue 48000160pool3: 4 buffers, 4576 bytes, queue 48000168slot1: VIP2, hw 2.2, sw 200.50, ccb 5800FF30, cmdq 48000088, vps 8192software loaded from systemFLASH ROM version 255.255FastEthernet1/0/0, addr 0000.0c41.6c20 (bia 0000.0c41.6c20)gfreeq 48000148, lfreeq 480001D0 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A00, txacc 48001A02 (value 0), txlimit 20Ethernet1/1/0, addr 0000.0c41.6c28 (bia 0000.0c41.6c28)gfreeq 48000148, lfreeq 480001D8 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A08, txacc 48001A0A (value 0), txlimit 20Ethernet1/1/1, addr 0000.0c41.6c29 (bia 0000.0c41.6c29)gfreeq 48000148, lfreeq 480001E0 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A10, txacc 48001A12 (value 0), txlimit 20Ethernet1/1/2, addr 0000.0c41.6c2a (bia 0000.0c41.6c2a)gfreeq 48000148, lfreeq 480001E8 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A18, txacc 48001A1A (value 0), txlimit 20Ethernet1/1/3, addr 0000.0c41.6c2b (bia 0000.0c41.6c2b)gfreeq 48000148, lfreeq 480001F0 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A20, txacc 48001A22 (value 0), txlimit 20Ethernet1/1/4, addr 0000.0c41.6c2c (bia 0000.0c41.6c2c)gfreeq 48000148, lfreeq 480001F8 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A28, txacc 48001A2A (value 0), txlimit 20Ethernet1/1/5, addr 0000.0c41.6c2d (bia 0000.0c41.6c2d)gfreeq 48000148, lfreeq 48000200 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A30, txacc 48001A32 (value 0), txlimit 20Ethernet1/1/6, addr 0000.0c41.6c2e (bia 0000.0c41.6c2e)gfreeq 48000148, lfreeq 48000208 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A38, txacc 48001A3A (value 0), txlimit 20Ethernet1/1/7, addr 0000.0c41.6c2f (bia 0000.0c41.6c2f)gfreeq 48000148, lfreeq 48000210 (1536 bytes), throttled 0rxlo 4, rxhi 30, rxcurr 0, maxrxcurr 0txq 48001A40, txacc 48001A42 (value 0), txlimit 20The following is partial sample output of the show controllers cbus command for a Packet over SONET Interface Processor (POSIP) in slot 0; its single Packet OC-3 interface is Posi0/0:
slot0: POSIP, hw 2.1, sw 200.01, ccb 5800FF30, cmdq 48000080, vps 8192software loaded from flash slot0:rsp_posip.newFLASH ROM version 160.4, VPLD version 2.2Posi0/0, applique is SONETgfreeq 48000148, lfreeq 48000158 (4480 bytes), throttled 0rxlo 4, rxhi 226, rxcurr 0, maxrxcurr 186txq 48000160, txacc 48000082 (value 150), txlimit 150The following is partial output of the show controllers cbus command for a Multichannel Interface Processor (MIP). Not all of the 23
