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Router Products Command Reference
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About This Manual
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Router Product Overview
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User Interface Commands
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System Image, Microcode Image, and Configuration File Load Comm
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Terminal Line and Modem Support Commands
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System Management Commands
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Interface Commands
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ATM Commands
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DDR Commands
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Frame Relay Commands
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ISDN Commands
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LAN Emulation Commands
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SMDS Commands
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X.25 Commands
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Apollo Domain Commands
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AppleTalk Commands
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Banyan VINES Commands
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DECnet Commands
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IP Commands
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IP Routing Protocols Commands
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ISO CLNS Commands
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Novell IPX Commands
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XNS Commands
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Source-Route Bridging Commands
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Remote Source-Route Bridging Commands
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DLSw+ Configuration Commands
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STUN and BSTUN Configuration Commands
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LLC2 and SDLC Configuration Commands
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IBM Network Media Translation Commands
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DSPU and SNA Service Point Configuration Commands
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SNA Frame Relay Access Support Commands
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APPN Configuration Commands
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IBM Channel Attach Configuration Commands
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References and Recommended Reading
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Ethernet Type Codes
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Regular Expressions
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ASCII character Set
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Platform Support
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Switching Appendix
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Table Of Contents
half-duplex controlled-carrier
service-module t1 clock source
service-module t1 remote-alarm-enable
service-module t1 remote-loopback
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
Interface Commands
This chapter contains the commands used to configure nonprotocol-specific interface features. For hardware technical descriptions, and for information about installing the router 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 Router Products Configuration Guide.
For information about the Channel Interface Processor (CIP), see the chapter entitled "IBM Channel Attach Commands." The CIP is described in a separate chapter because of the interrelationship of host system configuration values and router configuration values.
Note
Commands in this chapter that have been replaced by new commands continue to perform their normal functions in the current release but are no longer documented. 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
Related Commands
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
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
To assign the interface address that is used by the device connecting to the router via PPP or SLIP, unless you override the address at the command line, use the async default ip address interface configuration command. Use the no form of this command to remove the address from your configuration.
async default ip address ip-address
no async default ip addressSyntax Description
Default
No interface address is assigned.
Command Mode
Interface configuration
Example
The following example specifies address 182.32.7.51 on asynchronous interface 1:
interface async 1async default ip address 182.32.7.51Related Command
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
Example
The following example shows dynamic addressing assigned to an interface:
interface async 1async dynamic addressRelated Commands
ppp
slipasync dynamic routing
To implement asynchronous routing on an interface, use the async dynamic routing interface configuration command. The no form of this command disables use of routing protocols; static routing will still be used.
async dynamic routing
no async dynamic routingSyntax Description
This command has no arguments or keywords.
Default
Disabled
Command Mode
Interface configuration
Example
The following example shows how to enable asynchronous 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 passiveRelated Commands
A dagger (†) indicates that the command is documented in another chapter.
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. The no form of this command returns 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
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
To enable the slip and ppp EXEC commands, use the async mode interactive line configuration command. Use the no form of this command to prevent users from implementing 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
Example
The following example enables the ppp and slip EXEC commands:
interface async 1async mode interactiveRelated Commands
async mode dedicated
ppp
slipauto-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 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
backup delay
To define how much time should elapse before a secondary line is set up or taken down after a primary line transition, use the backup delay interface configuration command. Use the no form of this command to remove the definition.
backup delay {enable-delay | never} {disable-delay | never}
no backup delay {enable-delay | never} {disable-delay | never}Syntax Description
Default
never
Command Mode
Interface configuration
Usage Guidelines
When a primary line goes down, the router 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 router 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 with the appropriate serial port designation to turn disable this feature.
backup interface serial number
backup interface serial slot/port (for the Cisco 7000 series)
no backup interface serial number
no backup interface serial slot/port (for the Cisco 7000 series)Syntax Description
Default
Disabled
Command Mode
Interface configuration
Examples
The following example sets serial 1 as the backup line to serial 0:
interface serial 0backup interface serial 1Related Command
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
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
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 in another chapter.
channel-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
Use this command in configurations where the router is intended to 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
clear controller
Use the clear controller EXEC command to reset the T1 or E1 controller interface on the Cisco 7000 series or Cisco 4000 series routers.
clear controller {t1 | e1} slot/port (Cisco 7000)
clear controller {t1 | e1} number (Cisco 4000)Syntax Description
Command Mode
EXEC
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 Command
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 series)Syntax Description
Command Mode
Privileged EXEC
Usage Guidelines
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] [ethernet | serial]
clear counters [type slot/port] [ethernet | serial] (for the Cisco 7000 series)Syntax Description
Command Mode
EXEC
Usage Guidelines
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
Table 6-1 Clear Counters Interface Type Keywords
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
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
Example
The following example clears hub 0:
clear hub ethernet 0Related Command
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
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
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)
clear interface type slot/port [:channel-group] (on a Cisco 7000 MIP T1 interface)Syntax Description
Command Mode
EXEC
Usage Guidelines
Under normal circumstances, you do not need to clear the hardware logic on interfaces.
Table 6-2 Clear Interface Type Keywords
Example
The following example resets the interface logic on HSSI interface 1:
clear interface hssi 1clear 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
Example
The following example illustrates how to clear the RIF cache:
clear rif-cacheRelated Command
A dagger (†) indicates that the command is documented in another chapter.
multiring †
clear service-module
To reset the CSU/DSU, use the clear service-module privileged EXEC configuration command.
clear service-module interface
Syntax Description
Default
None
Command Mode
Privileged EXEC
Usage Guidelines
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 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.
Related 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 (IPs) 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
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 RS-232 signaling. It is recommended that you only use the synchronous serial RS-232 signal at speeds up to 64,000 bits per second. To permit a faster speed, use an RS-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 (controller)
Use the clock source controller configuration command to set the T1-line clock-source for the MIP in the Cisco 7000 or for the NIM in the Cisco 4000.
clock source {line | internal}
Syntax Description
line
Specifies the T1 line as the clock source.
internal
Specifies the MIP (Cisco 7000) or the NIM (Cisco 4000) as the clock source.
Default
T1 line
Command Mode
Controller configuration
Usage Guidelines
This command is used in configurations where the interfaces are connected back-to-back, rather than to a T1 line, and one of the interfaces must provide a clocking signal. When the interface is connected to a channelized T1 line, this command need never be used.
Example
The following example enables internal clocking:
clock source internalRelated Commands
clock 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 applies to a Cisco 4000 router or Cisco 7000 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
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 zero:
cmt connect fddi 0The following command on the Cisco 7000 starts both fibers on the FDDI interface unit zero:
cmt connect fddi 1/0The following command starts only Physical Sublayer A on the FDDI interface unit 0 (zero):
cmt connect fddi 0 phy-aThe following command on the Cisco 7000 starts only Physical Sublayer A on the FDDI interface unit 0 (zero):
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
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 zero:
cmt disconnect fddi 0The following command on the Cisco 7000 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 (zero). 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 stops only Physical Sublayer A on the FDDI interface unit 0 (zero). 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), Point-to-Point Protocol (PPP), 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
Default
Compression is disabled.
Command Mode
Interface configuration
Usage Guidelines
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. LAPB encapsulation supports 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.
Table 6-3 Compression Guidelines for LAPB Encapsulations
Predictor
The bottleneck is the load on the router.
Stacker
The bottleneck is line bandwidth.
None
Most files are already compressed.
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 maximim 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 in another 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)
controller [t1 | e1] number (on the Cisco 4000)
Syntax Description
Default
No T1 or E1 controller is configured.
Command Mode
Global configuration
Usage Guidelines
This comm
