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This chapter contains the commands used to configure nonprotocol-specific interface features. The commands are in alphabetical order. For hardware technical descriptions and for information about installing the communication server interfaces, refer to the hardware installation and maintenance publication for your product.
For interface configuration tasks and examples, refer to the Access and Communication Servers Configuration Guide.
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}
enable-delay | Integer argument that specifies the delay in seconds after the primary line goes down before the secondary line is activated |
disable-delay | Integer argument that specifies the delay in seconds after the primary line goes up before the secondary line is deactivated |
never | Keyword that is specified to prevent the secondary line from being activated or deactivated |
A secondary line is never activated nor deactivated.
Interface configuration
When a primary line goes down, the communication server delays the number 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 communication server will delay by the number of seconds defined by the disable-delay argument.
In cases where there are spurious signal disruptions that might appear as intermittent lost carrier signals, it is recommended that some delay be enabled before activating and deactivating a secondary.
The interval configured with the backup delay command does not affect the operation of the backup load command.
The following example sets a 10-second delay on deactivating the secondary line; however, the line is activated immediately:
interface serial 0 backup delay 0 10
To configure the serial interface as a secondary, or dial backup line, use the backup interface interface configuration command. Use the no form of this command with the appropriate serial port designation to turn this feature off.
backup interface interface-name
interface-name or type | Serial port to be set as the secondary interface line |
None
Interface configuration
The following example sets serial interface 1 as the backup line to serial interface 0:
interface serial 0 backup interface serial 1
down-when-looped
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}
enable-threshold | Integer argument that specifies a percentage of the primary line's available bandwidth |
disable-load | Integer argument that specifies a percentage of the primary line's available bandwidth |
never | Keyword that sets the secondary line to never be activated due to load |
The secondary line is never activated due to load.
Interface configuration
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 an disable-load value, the secondary line is never deactivated because of load.
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 0 backup load 60 5
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
kilobits | Intended bandwidth in kilobits per second. For a full bandwidth DS3, enter the value 44736. |
Default bandwidth values are set during startup.
Interface configuration
Bandwidth values can be displayed with the EXEC command show interfaces.
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.
The following example sets the full bandwidth for DS3 transmissions:
interface serial 0
bandwidth 44736
To clear the interface counters, use the clear counters EXEC command.
clear counters [type number]
(Optional) Specifies the interface type; it is one of the keywords listed in Table 6-1. | |
number | (Optional) Specifies the interface counter displayed with the show interfaces command. |
| Keyword | Interface Type |
|---|---|
async | Asynchronous serial interface |
dialer | Dialer interface |
ethernet | Ethernet interface |
loopback | Loopback interface |
null | Null interface |
serial | Synchronous serial interface |
tokenring | Token Ring interface |
tunnel | Tunnel interface |
EXEC
This command clears all the current interface counters from the interface unless the optional arguments type-keyword and number are specified to clear only a specific interface type (serial, Ethernet, Token Ring, and so on).
The following example illustrates how to clear all interface counters:
cs# clear counters
show interfaces
To reset the hardware logic on an interface, use the clear interface EXEC command.
clear interface type number
Specifies the interface type; it is one of the keywords listed in Table 6-2. | |
number | Specifies the port, connector, or interface card number. |
| Keyword | Interface Type |
|---|---|
async | Asynchronous serial interface |
ethernet | Ethernet interface |
loopback | Loopback interface |
null | Null interface |
serial | Synchronous serial interface |
tokenring | Token Ring interface |
tunnel | Tunnel interface |
EXEC
Under normal circumstances, you do not need to clear the hardware logic on interfaces.
cs# clear interface async 1
To return a line to its idle state, enter the clear line privileged EXEC command at the system prompt.
clear line line-number
line-number | Asynchronous line port number assigned with the interface async command |
Privileged EXEC
Normally, this command returns the line to its conventional function as a terminal line, with the interface left in a "down" state.
The following example shows how to use the clear line command to return serial interface 5 to its idle state:
clear line 5
To configure the clock rate for appliques (connector hardware) on the serial interface of the MCI and SCI cards to an acceptable bit rate, use the clockrate interface configuration command. Use the no form of this command to remove the clock rate if you change the interface from a DCE to a DTE device.
clockrate bps
bps | Desired clock rate in bits per second: 1200, 2400, 4800, 9600, 19200, 34800, 56000, 64000, 72000, 125000, 148000, 500000, 800000, 1000000, 1300000, 2000000, or 4000000 |
No clock rate
Interface configuration
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.
The following example sets the clock rate on the first serial interface to 64,000 bits per second:
interface serial 0
clockrate 64000
To configure point-to-point software compression for a LAPB, PPP, and HDLC, use the compress interface configuration command. To disable compression, use the no form of this command.
compress [predictor | stac]
predictor | Specifies that a predictor compression algorithm will be used on LAPB and PPP encapsulation. |
stac | Specifies that a Stacker (LZS) compression algorithm will be used on HDLC and PPP encapsulation. |
Compression is disabled.
Interface configuration
You can configure point-to-point software compression for all LAPB, point-to-point (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%. 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.
If the majority of your traffic is already compressed files, it is recommended 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.
Table 6-3 provides general guidelines for deciding which compression type to select for LAPB encapsulations.
| Compression Type to Use | Situation |
|---|---|
Predictor | The bottleneck is the load on the communication server. |
Stacker | The bottleneck is line bandwidth. |
None | Most files are already compressed. |
Stacker compression for LAPB encapsulations reaches its performance ceiling on T1lines; it is not recommended for faster lines because the added processing will slow their performance.
When using predictor compression, you should adjust the MTU for the serial interface and the LAPB 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.
The following example enables predictor compression on serial interface 0 for a LAPB link:
interface serial 0 encapsulation lapb compress predictor mtu 1509 lapb n1 12072
The 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); it is recommended that you do not change those LAPB parameters for Stacker compression:
interface serial 0 encapsulation lapb compress predictor
encapsulation lapb
encapsulation lapb-dce
encapsulation multi-lapb
encapsulation multi-lapb-dce
encapsulation x25
show compress
show processes
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
tens-of-microseconds | Integer that specifies the delay in tens of microseconds for an interface or network segment |
You can display default delay values with the EXEC command show interfaces.
Interface configuration
The following example sets a 30,000-microsecond delay on serial interface 3:
interface serial 3
delay 30000
show interfaces
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
string | Comment or description to help you remember what is attached to this interface |
None
Interface configuration
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 configuration, show interfaces, and write terminal.
The following example describes a 3174 controller on serial interface 0:
interface serial 0
description 3174 Controller for test lab
A dagger (†) indicates that the command is documented in another chapter.
show configuration †
show interfaces
write terminal †
To configure an interface to inform the system it is down when loopback is detected, use the
down-when-looped interface configuration command.
This command has no arguments or keywords.
Disabled
Interface configuration
This command is valid for 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.
In the following example, serial interface 0 is configured for PPP encapsulation. It is then configured to let the system know that it is down when in loopback mode.
interface serial 0 encapsulation ppp down-when-looped
backup interface
loopback
To enable early token release, use the early-token-release interface configuration command. Use the no form of this command to disable this feature.
early-token-releaseThis command has no arguments or keywords.
Disabled
Interface configuration
This feature helps to increase the total bandwidth of the Token Ring. 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.
The CSC-R16M, CSC-2R, and CSC-1R cards support early token release.
The following example enables the use of early token release on Token Ring interface 1:
interface tokenring 1 early-token-release
To set the encapsulation method used by the interface, use the encapsulation interface configuration command.
encapsulation encapsulation-type
encapsulation-type | Encapsulation type. See Table 6-4 for a list of supported encapsulation types. |
| Keyword | Encapsulation Type |
|---|---|
arpa | This encapsulation uses a 16-bit protocol type code. |
bfex25 | Blacker Front End Encryption X.25 operation (for serial interface) |
ddnx25-dce | DDN X.25 DCE operation (for serial interface) |
ddnx25 | DDN X.25 DTE operation (for serial interface) |
frame-relay | Frame Relay (for serial interface) |
hdlc | High-Level Data Link Control (HDLC) protocol for serial interface. This encapsulation method provides the synchronous framing and error detection functions of HDLC without windowing or retransmission. |
sap | IEEE 802.3 encapsulation. In this encapsulation, the type code becomes the frame length for the IEEE 802.2 LLC encapsulation (destination and source Service Access Points and a control byte). |
lapb | X.25 LAPB DTE operation (for serial interface) |
lapb-dce | X.25 LAPB DCE operation (for serial interface) |
multip-lapb | X.25 LAPB multiprotocol DTE operation (for serial interface) |
multi-lapb-dce | X.25 LAPB multiprotocol DCE operation (for serial interface) |
ppp | Point-to-Point Protocol (PPP) (for serial interface) |
smds | Switched Multimegabit Data Services (SMDS) (for serial interface) |
snap | IEEE 802.2 Ethernet media. This encapsulation is specified in RFC 1042 and allows Ethernet protocols to run on IEEE 802.2 media. |
x25-dce | X.25 DCE operation (for serial interface) |
x25 | X.25 DTE operation (for serial interface) |
The default depends on the type of interface. For example, an Ethernet interface defaults to ARPA.
Interface configuration
The following example reenables standard Ethernet Version 2.0 encapsulation on Ethernet interface 0:
interface ethernet 0encapsulation arpa
The following example sets IEEE 802.3 encapsulation on Ethernet interface 1:
interface ethernet 1
encapsulation sap
The following example enables PPP encapsulation on serial interface 0:
interface serial 0 encapsulation ppp
The following example sets IEEE 802.2 encapsulation on Ethernet interface 1:
interface ethernet 1
encapsulation snap
A dagger (†) indicates that the command is documented in another chapter.
keepalive
ppp †
ppp authentication chap
slip †
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
milliseconds | Frequency at which the error recount will be set in milliseconds |
1000 milliseconds
Interface configuration
The following commands set the error recount threshold on Ethernet interface 2 to 10,000 milliseconds:
interface ethernet 2
error-threshold 10000
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}
length | An integer that specifies the maximum number of packets in the queue |
in | A keyword that specifies the input queue |
out | A keyword that specifies the output queue |
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.
Interface configuration
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.
The following example illustrates how to set a small input queue on a slow serial line:
interface serial 0
hold-queue 30 in
show interfaces
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-dcdThis command has no arguments or keywords.
The serial interface, operating in DTE mode, monitors the DCD signal as the line up/down indicator.
Interface configuration
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.
The following example configures serial interface 0 to monitor the DSR signal as the line up/down indicator:
interface serial 0 ignore-dcd
To configure an interface type and enter interface configuration mode, use the interface global configuration command.
interface type numberTo configure a subinterface, use the interface global configuration command.
interface type number.subinterface-number [multipoint | point-to-point]
Type of interface to be configured. See Table 6-5. | |
number | Port, connector, or interface card number. The numbers are assigned at the factory at the time of installation or when added to a system, and can be displayed with the show interfaces command. |
.subinterface-number | Subinterface number in the range 1 to 4294967293. The number that precedes the period (.) must match the number to which this subinterface belongs. |
multipoint | point-to-point | (Optional) Specifies a multipoint or point-to-point subinterface. Default is multipoint. |
| Keyword | Interface Type |
|---|---|
async | Line used as an asynchronous interface. |
dialer | Dialer interface. |
ethernet | Ethernet IEEE 802.3 interface. |
Software-only loopback interface that emulates an interface that is always up. It is a virtual interface supported on all platforms. The interface-number is the number of the loopback interface that you want to create or configure.There is no limit on the number of loopback interfaces you can create. | |
null | Null interface. |
serial | Serial interface. |
tokenring | Token Ring interface. |
tunnel | Tunnel interface; a virtual interface. The interface-number is the number of the tunnel interface that you want to create or configure. There is no limit on the number of tunnel interfaces you can create. |
The default mode for subinterfaces is multipoint.
Global configuration
In the following example, serial interface 0 is configured with PPP encapsulation:
interface serial 0
encapsulation ppp
The 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 131.108.1.1 255.255.255.0
The 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 0 encapsulation frame-relay interface serial 0.1 multipoint ip address 131.108.10.1 255.255.255.0 frame-relay interface-dlci 42 broadcast frame-relay interface-dlci 53 broadcast interface serial 0.2 point-to-point ip address 131.108.11.1 255.255.0 frame-relay interface-dlci 59 broadcast
Two daggers (††) indicate that the command is documented in the Cisco Access Connection Guide.
ppp ††
show interfaces
slip ††
To designate a dialer rotary group leader, use the interface dialer global configuration command.
interface dialer interface-number
interface-number | Integer that you select to indicate a dialer rotary group in the range 0 to 9 |
None
Global configuration
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 indicating that each 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.
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 1
encapsulation ppp
dialer in-band
dialer map ip 131.108.2.5 username YYY 14155553434
dialer map ip 131.126.4.5 username ZZZ
A dagger (†) indicates that the command is documented in another chapter.
dialer rotary-group †
To make temporary IP addresses available for dial-in asynchronous clients using SLIP/PPP, use the ip address-pool command. Use the no form of the command to disable IP address pooling on all interfaces.
ip address-pool dhcp-proxy-clientThis command has the mandatory argument of dhcp-proxy-client.
IP address pooling is not enabled.
Global configuration
The ip address-pool command allows you to use a communication server as the intermediary (a proxy-client) between a third-party DHCP server and clients dialing in to the communication server on asynchronous interfaces. If this command is issued and no DHCP servers have been defined using the ip dhcp server command, the communication server will use the limited address of 255.255.255.255 to communicate with available DHCP servers on the network.
A DHCP server temporarily allocates network addresses to clients through the communication 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.
In normal situations, if a SLIP/PPP session fails (for example if a modem line disconnects), the allocated address will be temporarily reserved so that the client will receive the same IP address when it dials back into the server. This way, the session that was accidentally terminated can be resumed.
The ip address-pool command initializes proxy-client status to all interfaces on the communication server defined as asynchronous. To selectively disable proxy-client status on a single asynchronous interface, use the no peer default ip address pool interface command.
The following example enables DHCP proxy-client status on all asynchronous interfaces on the communication server:
ip address-pool dhcp-proxy-client
A dagger (†) indicates that the command is documented in another chapter.
ip dhcp-server
peer default ip address pool
show dhcp
interface async†
encapsulation†
ppp†
To specify which DHCP (Dynamic Host Configuration Protocol) servers to use on your network, specify the IP address of one or more DHCP servers available on the network by using the ip dhcp-server command. Use the no form of the command to remove a DHCP server's IP address.
ip dhcp-server [ip-address | name]
ip-address | IP address of a DHCP server. You can specify up to ten servers on the network. |
name | Name of a DHCP server. You can specify up to ten servers on the network. |
The IP limited broadcast address of 255.255.255.255 is used for transactions if no DHCP server is specified. This allows auto-detection of DHCP servers.
Global configuration
By default, the DHCP proxy-client feature uses the IP address of 255.255.255.255 to discover and interact with DHCP servers. 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. To use the DHCP proxy-client feature, enable your communication server to be a proxy-client on asynchronous interfaces by using the ip address-pool dhcp-proxy-client command.
The following command specifies a DHCP server with the IP address of 129.12.13.81:
ip dhcp-server 129.12.13.81
A dagger (†) indicates that the command is documented in another chapter.
ip address-pool dhcp-proxy-client
ip helper address †
peer default ip address pool
show dhcp
Use the keepalive interface configuration command to set the keepalive timer for a specific interface. The no keepalive command turns off keepalives entirely.
keepalive [seconds]
seconds | (Optional) Unsigned integer value greater than 0. The default is 10 seconds. |
10 seconds
Interface configuration
You can configure the keepalive interval, which is the frequency at which the communication server 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). Since this sort of failure is typically noticed within a few milliseconds, adjusting the keepalive timer for quicker routing recovery is generally not useful.
The following example sets the keepalive interval to 3 seconds:
interface ethernet 0 keepalive 3
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 remoteThis command has no arguments or keywords.
Disabled
Interface configuration
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."
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
The following example configures a remote loopback test:
interface serial 0
loopback remote
show interfaces loopback
To loop packets to DTE internally within the CSU/DSU at the DTE interface, use the loopback interface configuration command. Use the no form of this command to remove the loop.
loopback dteThis command has no arguments or keywords.
Disabled
Interface configuration
The following example configures the loopback test on the DTE interface:
interface serial 1
loopback dte
To loop packets completely through the CSU/DSU to configure the CSU loop, use the loopback line interface configuration command. Use the no form of this command to remove the loop.
loopback lineThis command has no arguments or keywords.
Disabled
Interface configuration
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.
The following example configures the loopback test on the DCE device:
interface serial 1
loopback line
show interfaces loopback
To loop packets completely through the CSU/DSU, over the DS3 link, to the remote CSU/DSU and back, use the loopback remote interface configuration command. Use the no form of this command to remove the loop.
loopback remoteThis command has no arguments or keywords.
Disabled
Interface configuration
This command is useful for testing the DCE device (CSU/DSU) itself.
This command applies only when the device supports the remote 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.
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
The following example configures a remote loopback test:
interface serial 0
loopback remote
show interfaces loopback
To enable an interface to support the Maintenance Operation Protocol (MOP), use the mop enabled interface configuration command. Use the no form of this command to disable MOP on an interface.
mop enabledThis command has no arguments or keywords.
Enabled by default on Ethernet interfaces and disabled on all other interfaces.
Interface configuration
In the following example, MOP is enabled for serial interface 0:
interface serial 0 mop enabled
A dagger (†) indicates that the command is documented in another chapter.
mop sysid
mop restransmit-timer †
mop retries †
To enable an interface to send out periodic Maintenance Operation Protocol (MOP) system identification messages, use the mop sysid interface configuration command. Use the no form of this command to disable MOP message support on an interface.
mop sysidThis command has no arguments or keywords.
Enabled
Interface configuration
You can 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.
In the following example, serial interface 0 is enabled to send MOP system identification messages:
interface serial0 mop sysid
A dagger (†) indicates that the command is documented in another chapter.
mop device-code †
mop enabled
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
bytes | Desired size in bytes |
Table 6-6 lists default MTU values according to media type.
| Media Type | Default MTU |
|---|---|
Ethernet | 1500 |
Serial | 1500 |
Token Ring | 4464 |
Interface configuration
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.
The following example specifies an MTU of 1000 bytes:
interface serial 1
mtu 1000
A dagger (†) indicates that the command is documented in another chapter.
encapsulation smds †
ip mtu †
You can selectively disable DHCP proxy-client status on an individual asynchronous interface on a communication server by using the no peer default ip address pool command. You can turn a single interface back on by issuing the standard command after it is turned off.
peer default ip address poolThis command has no arguments or keywords.
DHCP proxy-client status is not enabled until the ip address-pool command is issued, at which time the DHCP proxy-client feature is enabled on all asynchronous ports.
Interface configuration
The no peer default ip address pool command turns off DHCP proxy-client status on individual asynchronous interfaces that are globally turned on with the ip address-pool dhcp-proxy-client command. If you have disabled DHCP on a given interface, you can re-enable DHCP on this interface by issuing the standard peer default ip address pool command. You cannot enable DHCP on any interface until the ip address-pool dhcp-proxy-client command is issued.
The following command disables DHCP proxy-client status on the current asynchronous interface:
no peer default ip address pool
A dagger (†) indicates that the command is documented in another chapter.
ip address-pool dhcp-proxy-client
ip dhcp-server
show dhcp
interface async†
encapsulation†
ppp†
To enable Challenge Handshake Authentication Protocol (CHAP) or Password Authentication Protocol (PAP), and to enable a TACACS+ authorization method on a serial interface, use the ppp authentication interface configuration command. Use the no form of the command to disable this authentication.
ppp authentication {chap | pap} [if-needed] [listname]
chap | Enable CHAP on a serial interface. |
pap | Enable PAP on a serial interface. |
if-needed | (Optional) Used with TACACS and XTACACS. Do not perform CHAP or PAP authentication if the user has already provided authentication. This option is available only on asynchronous interfaces. |
list-name | (Optional) Used with AAA/TACACS+. Specify the name of a list of TACACS+ methods of authentication to use. If no listname is specified, the system uses the default. Lists and default are created with the aaa authentication ppp command. |
PPP authentication is not enabled.
Interface configuration
Once you have enabled CHAP or PAP, the local communication server requires a password from remote devices. If the remote device does not support CHAP or PAP, no traffic will be passed to that device.
If you are using autoselect on a tty line, you will probably want to use the ppp authentication command to turn on PPP authentication for the corresponding interface.
When you specify the if-needed option, PPP authentication is not required when the user has already provided authentication. This option is useful in conjunction with the autoselect command, but cannot be used with AAA/TACACS+.
The list-name keyword can only be used when AAA/TACACS+ has been initialized and cannot be used with the if-needed argument.
 | Caution If you use a list-name that has not been configured with the aaa authentication ppp command, you disable PPP on this line. |
The following example enables CHAP on asynchronous interface 4:
interface async 4
encapsulation ppp
ppp authentication chap
A dagger (†) indicates that the command is documented in another chapter.
aaa authentication ppp†
aaa new-model
autoselect†
encapsulation ppp†
ppp use-tacacs†
username†
To enable Link Quality Monitoring (LQM) on a serial interface, use the ppp quality interface configuration command. Use the no form of this command to disable LQM.
ppp quality percentage
percentage | Specifies the link quality threshold. The range is 1 to 100. |
Disabled
Interface configuration
The percentages are calculated for both incoming and outgoing directions. The outgoing quality is calculated by comparing the total number of packets and bytes sent to the total number of packets and bytes received by the peer. The incoming quality is calculated by comparing the total number of packets and bytes received to the total number of packets and bytes sent by the peer.
If the link quality percentage is not maintained, the link is deemed to be of poor quality and is taken down. The policy implements a time lag so that the link does not bounce up and down.
The following example enables LQM on serial interface 0:
interface serial 0
encapsulation ppp
ppp quality 80
A dagger (†) indicates that the command is documented in another chapter.
encapsulation ppp
keepalive †
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
seconds | Integer that specifies the DTR signal interval in seconds |
0 seconds
Interface configuration
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.
The following example enables DTR pulse signals for three seconds on serial interface 0:
interface serial 0
pulse-time 3
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
speed | Integer that specifies the ring speed, either 4 for 4-Mbps or 16 for 16-Mbps operation |
16-Mbps operation
Interface configuration
| Caution Configuring 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. |
The following example sets a Token Ring interface ring speed to 4 Mbps:
interface tokenring 0
ring-speed 4
To control the maximum amount of time that can elapse without running the lowest priority system processes, use the scheduler-interval global configuration command. Use the no form of this command to restore the default.
scheduler-interval milliseconds
milliseconds | An integer that specifies the interval in milliseconds. The minimum interval that you can specify is 500 milliseconds; there is no maximum value. |
The default is to allow high-priority operations to use as much of the central processor as needed.
Global configuration
The normal operation of the network server allows the switching operations to use as much of the central processor as is required. If the network is running unusually heavy loads that do not allow the processor the time to handle the routing protocols, give priority to the system process scheduler.
The following example changes the low-priority process schedule to an interval of 750 milliseconds:
scheduler-interval 750
To list the status of asynchronous interfaces, use the show async status EXEC command:
show async statusThis command has no arguments or keywords.
EXEC
This command shows all asynchronous sessions, whether they are using SLIP or PPP encapsulation.
The following is sample output from the show async status command:
cs> show async status
Async protocol statistics:
Rcvd: 5448 packets, 7682760 bytes
1 format errors, 0 checksum errors, 0 overrun, 0 no buffer
Sent: 5455 packets, 7682676 bytes, 0 dropped
Int Local Remote Qd InPack OutPac Inerr Drops MTU Qsz
1 192.31.7.84 Dynamic 0 0 0 0 0 1500 10
Table 6-7 describes significant fields shown in the display.
| Field | Description |
|---|---|
| Rcvd | Statistics on packets received. |
5548 packets | Packets received. |
7682760 bytes | Total number of bytes. |
1 format errors | Packets with a bad IP header, even before the checksum is calculated. |
0 checksum errors | Count of checksum errors. |
0 overrun | Number of giants received. |
0 no buffer | Number of packets received when no buffer was available. |
| Sent | Statistics on packets sent. |
5455 packets | Packets sent. |
7682676 bytes | Total number of bytes. |
0 dropped | Number of packets dropped. |
Int | Interface number. |
* | Line currently in use. |
Local | Local IP address on the link. |
Remote | Remote IP address on the link; "Dynamic" indicates that a remote address is allowed but has not been specified; "None" indicates that no remote address is assigned or being used. |
Qd | Number of packets on hold queue (Qsz is max). |
InPack | Number of packets received. |
OutPac | Number of packets sent. |
Inerr | Number of total input errors; sum of format errors, checksum errors, overruns and no buffers. |
Drops | Number of packets received that would not fit on the hold queue. |
MTU | Current maximum transmission unit size. |
Qsz | Current output hold queue size. |
interface async
To display compression statistics on a serial interface, use the show compress EXEC command.
show compressThis command has no arguments or keywords.
EXEC
The following is sample output from the show compress command:
cs# show compress Serial0 uncompressed bytes xmt/rcv 10710562/11376835 1 min avg ratio xmt/rcv 2.773/2.474 5 min avg ratio xmt/rcv 4.084/3.793 10 min avg ratio xmt/rcv 4.125/3.873 no bufs xmt 0 no bufs rcv 0 resets 0
Table 6-8 describes the fields shown in the display.
| Field | Description |
|---|---|
Serial0 | Name and number of the interface |
uncompressed bytes xmt/rcv | Total number of uncompressed bytes sent and received |
1 min avg ratio xmt/rcv | Static compression ratio for bytes sent and received, averaged over 1, 5, and 10 minutes |
no bufs xmt | Number of times buffers were not available to compress data being sent |
no bufs rcv | Number of times buffers were not available to uncompress data being received |
resets | Number of resets |
compress predictor
Use the show controllers ethernet EXEC command to display information on the Cisco 2500.
show controllers ethernet interface-number
interface-number | Interface number of the Ethernet interface. |
EXEC
The following is sample output from the show controllers ethernet command:
cs# show controllers ethernet 0 LANCE unit 0, NIM slot 1, NIM type code 4, NIM version 1 Media Type is 10BaseT, Link State is Up, Squelch is Normal idb 0x4060, ds 0x5C80, regaddr = 0x8100000 IB at 0x600D7AC: mode=0x0000, mcfilter 0000/0001/0000/0040 station address 0000.0c03.a14f default station address 0000.0c03.a14f buffer size 1524 RX ring with 32 entries at 0xD7E8 Rxhead = 0x600D8A0 (12582935), Rxp = 0x5CF0(23) 00 pak=0x60336D0 ds=0x6033822 status=0x80 max_size=1524 pak_size=98 01 pak=0x60327C0 ds=0x6032912 status=0x80 max_size=1524 pak_size=98 02 pak=0x6036B88 ds=0x6036CDA status=0x80 max_size=1524 pak_size=98 03 pak=0x6041138 ds=0x604128A status=0x80 max_size=1524 pak_size=98 04 pak=0x603FAA0 ds=0x603FBF2 status=0x80 max_size=1524 pak_size=98 05 pak=0x600DC50 ds=0x600DDA2 status=0x80 max_size=1524 pak_size=98 06 pak=0x6023E48 ds=0x6023F9A status=0x80 max_size=1524 pak_size=1506 07 pak=0x600E3D8 ds=0x600E52A status=0x80 max_size=1524 pak_size=1506 08 pak=0x6020990 ds=0x6020AE2 status=0x80 max_size=1524 pak_size=386 09 pak=0x602D4E8 ds=0x602D63A status=0x80 max_size=1524 pak_size=98 10 pak=0x603A7C8 ds=0x603A91A status=0x80 max_size=1524 pak_size=98 11 pak=0x601D4D8 ds=0x601D62A status=0x80 max_size=1524 pak_size=98 12 pak=0x603BE60 ds=0x603BFB2 status=0x80 max_size=1524 pak_size=98 13 pak=0x60318B0 ds=0x6031A02 status=0x80 max_size=1524 pak_size=98 14 pak=0x601CD50 ds=0x601CEA2 status=0x80 max_size=1524 pak_size=98 15 pak=0x602C5D8 ds=0x602C72A status=0x80 max_size=1524 pak_size=98 16 pak=0x60245D0 ds=0x6024722 status=0x80 max_size=1524 pak_size=98 17 pak=0x6008328 ds=0x600847A status=0x80 max_size=1524 pak_size=98 18 pak=0x601EB70 ds=0x601ECC2 status=0x80 max_size=1524 pak_size=98 19 pak=0x602DC70 ds=0x602DDC2 status=0x80 max_size=1524 pak_size=98 20 pak=0x60163E0 ds=0x6016532 status=0x80 max_size=1524 pak_size=98 21 pak=0x602CD60 ds=0x602CEB2 status=0x80 max_size=1524 pak_size=98 22 pak=0x6037A98 ds=0x6037BEA status=0x80 max_size=1524 pak_size=98 23 pak=0x602BE50 ds=0x602BFA2 status=0x80 max_size=1524 pak_size=98 24 pak=0x6018988 ds=0x6018ADA status=0x80 max_size=1524 pak_size=98 25 pak=0x6033E58 ds=0x6033FAA status=0x80 max_size=1524 pak_size=98 26 pak=0x601BE40 ds=0x601BF92 status=0x80 max_size=1524 pak_size=98 27 pak=0x6026B78 ds=0x6026CCA status=0x80 max_size=1524 pak_size=98 28 pak=0x6024D58 ds=0x6024EAA status=0x80 max_size=1524 pak_size=74 29 pak=0x602AF40 ds=0x602B092 status=0x80 max_size=1524 pak_size=98 30 pak=0x601FA80 ds=0x601FBD2 status=0x80 max_size=1524 pak_size=98 31 pak=0x6038220 ds=0x6038372 status=0x80 max_size=1524 pak_size=98 TX ring with 8 entries at 0xDA20, tx_count = 0 tx_head = 0x600DA58 (12582919), head_txp = 0x5DC4 (7) tx_tail = 0x600DA58 (12582919), tail_txp = 0x5DC4 (7) 00 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 01 pak=0x000000 ds=0x602126A status=0x03 status2=0x0000 pak_size=60 02 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 03 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 04 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 05 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 06 pak=0x000000 ds=0x600CF12 status=0x03 status2=0x0000 pak_size=118 07 pak=0x000000 ds=0x6003ED2 status=0x03 status2=0x0000 pak_size=126 0 missed datagrams, 0 overruns, 2 late collisions, 2 lost carrier events 0 transmitter underruns, 0 excessive collisions, 0 tdr, 0 babbles 0 memory errors, 0 spurious initialization done interrupts 0 no enp status, 0 buffer errors, 0 overflow errors 10 one_col, 10 more_col, 22 deferred, 0 tx_buff 0 throttled, 0 enabled Lance csr0 = 0x73
Use the show controllers mci privileged EXEC command to display all information about the Multiport Communications Interface card. This command displays information the system uses for bridging and routing that is specific to the interface hardware. The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.
show controllers mciThis command has no arguments or keywords.
Privileged EXEC
The following is sample output from the show controllers mci command:
cs# show controllers mci MCI 0, controller type 1.1, microcode version 1.8 128 Kbytes of main memory, 4 Kbytes cache memory 22 system TX buffers, largest buffer size 1520 Restarts: 0 line down, 0 hung output, 0 controller error Interface 0 is Ethernet0, station address 0000.0c00.d4a6 15 total RX buffers, 11 buffer TX queue limit, buffer size 1520 Transmitter delay is 0 microseconds Interface 1 is Serial0, electrical interface is V.35 DTE 15 total RX buffers, 11 buffer TX queue limit, buffer size 1520 Transmitter delay is 0 microseconds High speed synchronous serial interface Interface 2 is Ethernet1, station address aa00.0400.3be4 15 total RX buffers, 11 buffer TX queue limit, buffer size 1520 Transmitter delay is 0 microseconds Interface 3 is Serial1, electrical interface is V.35 DCE 15 total RX buffers, 11 buffer TX queue limit, buffer size 1520 Transmitter delay is 0 microseconds High speed synchronous serial interface
Table 6-9 describes significant fields shown in the display.
| Field | Description |
|---|---|
MCI 0 | Card type and unit number (varies depending on card) |
controller type 1.1 | Version number of the card |
microcode version 1.8 | Version number of the card's internal software (in read-only memory) |
128 Kbytes of main memory | Amount of main memory on the card |
4 Kbytes cache memory | Amount of cache memory on the card |
22 system TX buffers | Number of buffers that hold packets to be transmitted |
largest buffer size 1520 | Largest size of these buffers (in bytes) |
Restarts | Count of restarts due to the following conditions: |
Interface 0 is Ethernet0 | Names of interfaces, by number |
electrical interface is V.35 DTE | Line interface type for serial connections |
15 total RX buffers | Number of buffers for received packets |
11 buffer TX queue limit | Maximum number of buffers in transmit queue |
Transmitter delay is 0 microseconds | Delay between outgoing frames |
Station address 0000.0c00.d4a6 | Hardware address of the interface |
tx-queue-limit
Use the show controllers serial privileged EXEC command to display information that is specific to the interface hardware. The information displayed is generally useful for diagnostic tasks performed by technical support personnel only.
show controllers serialThis command has no arguments or keywords.
Privileged EXEC
Sample output of the show controllers serial command:
cs# show controllers serial
MK5 unit 0, NIM slot 1, NIM type code 7, NIM version 1
idb = 0x6150, driver structure at 0x34A878, regaddr = 0x8100300
IB at 0x6045500: mode=0x0108, local_addr=0, remote_addr=0
N1=1524, N2=1, scaler=100, T1=1000, T3=2000, TP=1
buffer size 1524
DTE V.35 serial cable attached
RX ring with 32 entries at 0x45560 : RLEN=5, Rxhead 0
00 pak=0x6044D78 ds=0x6044ED4 status=80 max_size=1524 pak_size=0
01 pak=0x60445F0 ds=0x604474C status=80 max_size=1524 pak_size=0
02 pak=0x6043E68 ds=0x6043FC4 status=80 max_size=1524 pak_size=0
03 pak=0x60436E0 ds=0x604383C status=80 max_size=1524 pak_size=0
04 pak=0x6042F58 ds=0x60430B4 status=80 max_size=1524 pak_size=0
05 pak=0x60427D0 ds=0x604292C status=80 max_size=1524 pak_size=0
06 pak=0x6042048 ds=0x60421A4 status=80 max_size=1524 pak_size=0
07 pak=0x60418C0 ds=0x6041A1C status=80 max_size=1524 pak_size=0
08 pak=0x6041138 ds=0x6041294 status=80 max_size=1524 pak_size=0
09 pak=0x60409B0 ds=0x6040B0C status=80 max_size=1524 pak_size=0
10 pak=0x6040228 ds=0x6040384 status=80 max_size=1524 pak_size=0
11 pak=0x603FAA0 ds=0x603FBFC status=80 max_size=1524 pak_size=0
12 pak=0x603F318 ds=0x603F474 status=80 max_size=1524 pak_size=0
13 pak=0x603EB90 ds=0x603ECEC status=80 max_size=1524 pak_size=0
14 pak=0x603E408 ds=0x603E564 status=80 max_size=1524 pak_size=0
15 pak=0x603DC80 ds=0x603DDDC status=80 max_size=1524 pak_size=0
16 pak=0x603D4F8 ds=0x603D654 status=80 max_size=1524 pak_size=0
17 pak=0x603CD70 ds=0x603CECC status=80 max_size=1524 pak_size=0
18 pak=0x603C5E8 ds=0x603C744 status=80 max_size=1524 pak_size=0
19 pak=0x603BE60 ds=0x603BFBC status=80 max_size=1524 pak_size=0
20 pak=0x603B6D8 ds=0x603B834 status=80 max_size=1524 pak_size=0
21 pak=0x603AF50 ds=0x603B0AC status=80 max_size=1524 pak_size=0
22 pak=0x603A7C8 ds=0x603A924 status=80 max_size=1524 pak_size=0
23 pak=0x603A040 ds=0x603A19C status=80 max_size=1524 pak_size=0
24 pak=0x60398B8 ds=0x6039A14 status=80 max_size=1524 pak_size=0
25 pak=0x6039130 ds=0x603928C status=80 max_size=1524 pak_size=0
26 pak=0x60389A8 ds=0x6038B04 status=80 max_size=1524 pak_size=0
27 pak=0x6038220 ds=0x603837C status=80 max_size=1524 pak_size=0
28 pak=0x6037A98 ds=0x6037BF4 status=80 max_size=1524 pak_size=0
29 pak=0x6037310 ds=0x603746C status=80 max_size=1524 pak_size=0
30 pak=0x6036B88 ds=0x6036CE4 status=80 max_size=1524 pak_size=0
31 pak=0x6036400 ds=0x603655C status=80 max_size=1524 pak_size=0
TX ring with 8 entries at 0x45790 : TLEN=3, TWD=7
tx_count = 0, tx_head = 7, tx_tail = 7
00 pak=0x000000 ds=0x600D70C status=0x38 max_size=1524 pak_size=22
01 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2
02 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2
03 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2
04 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2
05 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2
06 pak=0x000000 ds=0x600D70E status=0x38 max_size=1524 pak_size=2
07 pak=0x000000 ds=0x6000000 status=0x38 max_size=1524 pak_size=0
XID/Test TX desc at 0xFFFFFF, status=0x30, max_buffer_size=0, packet_size=0
XID/Test RX desc at 0xFFFFFF, status=0x0, max_buffer_size=0, packet_size=0
Status Buffer at 0x60459C8: rcv=0, tcv=0, local_state=0, remote_state=0
phase=0, tac=0, currd=0x00000, curxd=0x00000
bad_frames=0, frmrs=0, T1_timeouts=0, rej_rxs=0, runts=0
0 missed datagrams, 0 overruns, 0 bad frame addresses
0 bad datagram encapsulations, 0 user primitive errors
0 provider primitives lost, 0 unexpected provider primitives
0 spurious primitive interrupts, 0 memory errors, 0 tr
%LINEPROTO-5-UPDOWN: Linansmitter underruns
mk5025 registers: csr0 = 0x0E00, csr1 = 0x0302, csr2 = 0x0704
csr3 = 0x5500, csr4 = 0x0214, csr5 = 0x0008
To display information about memory management, error counters, and the CSC-1R, CSC-2R, and or CSC-R16M Token Ring interface cards, use the show controllers token privileged EXEC command.
show controllers tokenThis command has no arguments or keywords.
EXEC
Depending on the board being used, the output can vary. This command also displays information that is proprietary to Cisco Systems. Thus, the information that show controllers token displays is of primary use to Cisco technical personnel. Information that is useful to users can be obtained using the show interfaces tokenring command, described later in this chapter.
The following is sample output of the show controllers token command:
cs# show controllers token
TR Unit 0 is board 0 - ring 0
state 3, dev blk: 0x1D2EBC, mailbox: 0x2100010, sca: 0x2010000
current address: 0000.3080.6f40, burned in address: 0000.3080.6f40
current TX ptr: 0xBA8, current RX ptr: 0x800
Last Ring Status: none
Stats: soft:0/0, hard:0/0, sig loss:0/0
tx beacon: 0/0, wire fault 0/0, recovery: 0/0
only station: 0/0, remote removal: 0/0
Bridge: local 3330, bnum 1, target 3583
max_hops 7, target idb: 0x0, not local
Interface failures: 0 -- Bkgnd Ints: 0
TX shorts 0, TX giants 0
Monitor state: (active)
flags 0xC0, state 0x0, test 0x0, code 0x0, reason 0x0
f/w ver: 1.0, chip f/w: '000000.ME31100', [bridge capable]
SMT versions: 1.01 kernel, 4.02 fastmac
ring mode: F00, internal enables: SRB REM RPS CRS/NetMgr
internal functional: 0000011A (0000011A), group: 00000000 (00000000)
if_state: 1, ints: 0/0, ghosts: 0/0, bad_states: 0/0
t2m fifo purges: 0/0
t2m fifo current: 0, t2m fifo max: 0/0, proto_errs: 0/0
ring: 3330, bridge num: 1, target: 3583, max hops: 7
Packet counts:
receive total: 298/6197, small: 298/6197, large 0/0
runts: 0/0, giants: 0/0
local: 298/6197, bridged: 0/0, promis: 0/0
bad rif: 0/0, multiframe: 0/0
ring num mismatch 0/0, spanning violations 0
transmit total: 1/25, small: 1/25, large 0/0
runts: 0/0, giants: 0/0, errors 0/0
bad fs: 0/0, bad ac: 0
congested: 0/0, not present: 0/0
Unexpected interrupts: 0/0, last unexp. int: 0
Internal controller counts:
line errors: 0/0, internal errors: 0/0
burst errors: 0/0, ari/fci errors: 0/0
abort errors: 0/0, lost frame: 0/0
copy errors: 0/0, rcvr congestion: 0/0
token errors: 0/0, frequency errors: 0/0
dma bus errors: -/-, dma parity errors: -/-
Internal controller smt state:
Adapter MAC: 0000.3080.6f40, Physical drop: 00000000
NAUN Address: 0000.a6e0.11a6, NAUN drop: 00000000
Last source: 0000.a6e0.11a6, Last poll: 0000.3080.6f40
Last MVID: 0006, Last attn code: 0006
Txmit priority: 0006, Auth Class: 7FFF
Monitor Error: 0000, Interface Errors: FFFF
Correlator: 0000, Soft Error Timer: 00C8
Local Ring: 0000, Ring Status: 0000
Beacon rcv type: 0000, Beacon txmit type: 0000
Beacon type: 0000, Beacon NAUN: 0000.a6e0.11a6
Table 6-10 describes the fields shown in the following line of sample output.
TR Unit 0 is board 0 - ring 0
| Field | Description |
|---|---|
TR Unit 0 | Unit number assigned to the Token Ring interface associated with this output |
is board 0 | Board number assigned to the Token Ring controller board associated with this interface |
ring 0 | Number of the Token Ring associated with this board |
In the following output line, state 3 indicates the state of the board. The rest of this output line displays memory mapping that is of primary use to Cisco engineers.
state 3, dev blk: 0x1D2EBC, mailbox: 0x2100010, sca: 0x2010000
The following line also appears in show interface token output as the address and burned-in address, respectively:
current address: 0000.3080.6f40, burned in address: 0000.3080.6f40
The following line of output displays buffer management pointers that change by board:
current TX ptr: 0xBA8, current RX ptr: 0x800
The following line of output indicates the ring status from the controller chip set. This information is used by LAN Network Manager:
Last Ring Status: none
The following lines of output show Token Ring statistics. See the Token Ring specification for more information.
Stats: soft:0/0, hard:0/0, sig loss:0/0
tx beacon: 0/0, wire fault 0/0, recovery: 0/0
only station: 0/0, remote removal: 0/0
The following line of output indicates that Token Ring communication has been enabled on the interface. If this line of output appears, the message "Source Route Bridge capable" should appear in the show interfaces tokenring display.
Bridge: local 3330, bnum 1, target 3583
Table 6-11 describes the fields shown in the following line of sample output.
max_hops 7, target idb: 0x0, not local
| Field | Description |
|---|---|
max_hops 7 | Maximum number of bridges. |
target idb: 0x0 | Destination interface definition. |
not local | Indicates whether the interface has been defined as a local or remote bridge. |
The following line of output is specific to the hardware:
Interface failures: 0 -- Bkgnd Ints: 0
In the following line of output, TX shorts are the number of packets the interface transmits that are discarded because they are smaller than the medium's minimum packet size. TX giants are the number of packets the interface transmits that are discarded because they exceed the medium's maximum packet size.
TX shorts 0, TX giants 0
The following line of output indicates the state of the controller. Possible values include active, failure, inactive, and reset:
Monitor state: (active)
The following line of output displays detailed information relating to the monitor state shown in the previous line of output. This information relates to the firmware on the controller. This information is relevant to Cisco engineers only if the monitor state is something other than active.
flags 0xC0, state 0x0, test 0x0, code 0x0, reason 0x0
Table 6-12 describes the fields in the following line of output:
f/w ver: 1.0 expr 0, chip f/w: '000000.ME31100', [bridge capable]
| Field | Description |
|---|---|
f/w ver: 1.0 | Version of the Cisco firmware on the board. |
chip f/w: '000000.ME31100' | Firmware on the chip set. |
[bridge capable] | Interface has not been configured for bridging, but that it has that capability. |
The following line of output displays the version numbers for the kernel and the accelerator microcode of the Madge firmware on the board; this firmware is the LLC interface to the chip set:
SMT versions: 1.01 kernel, 4.02 fastmac
The following line of output displays LAN Network Manager information that relates to ring status:
ring mode: F00, internal enables: SRB REM RPS CRS/NetMgr
The following line of output corresponds to the functional address and the group address shown in show interfaces tokenring output:
internal functional: 0000011A (0000011A), group: 00000000 (00000000)
The following line of output displays interface board state information that is proprietary to Cisco Systems:
if_state: 1, ints: 0/0, ghosts: 0/0, bad_states: 0/0
The following output lines display information that is proprietary to Cisco Systems. Cisco engineers use this information for debugging purposes.
t2m fifo purges: 0/0 t2m fifo current: 0, t2m fifo max: 0/0, proto_errs: 0/0
Each of the fields in the following line of output maps to a field in the show source bridge display, as follows: ring maps to srn; bridge num maps to bn; target maps to trn; and max hops maps to max:
ring: 3330, bridge num: 1, target: 3583, max hops: 7
In the following lines of output, the number preceding the slash (/) indicates the count since the value was last displayed; the number following the slash (/) indicates count since the system was last booted:
Packet counts:
receive total: 298/6197, small: 298/6197, large 0/0
In the following line of output, the number preceding the slash (/) indicates the count since the value was last displayed; the number following the slash (/) indicates count since the system was last booted. The runts and giants values that appear here correspond to the runts and giants values that appear in show interfaces tokenring output.
runts: 0/0, giants: 0/0
The following lines of output are receiver-specific information that Cisco engineers can use for debugging purposes:
local: 298/6197, bridged: 0/0, promis: 0/0
bad rif: 0/0, multiframe: 0/0
ring num mismatch 0/0, spanning violations 0
transmit total: 1/25, small: 1/25, large 0/0
runts: 0/0, giants: 0/0, errors 0/0
The following output lines include very specific statistics that are not relevant in most cases, but exist for historical purposes. In particular, the internal errors, burst errors, ari/fci, abort errors, copy errors, frequency errors, dma bus errors, and dma parity errors fields are not relevant.
Internal controller counts: line errors: 0/0, internal errors: 0/0 burst errors: 0/0, ari/fci errors: 0/0 abort errors: 0/0, lost frame: 0/0 copy errors: 0/0, rcvr congestion: 0/0 token errors: 0/0, frequency errors: 0/0 dma bus errors: -/-, dma parity errors: -/-
The following lines of output are low-level Token Ring interface statistics relating to the state and status of the Token Ring with respect to all other Token Rings on the line:
Internal controller smt state: Adapter MAC: 0000.3080.6f40, Physical drop: 00000000 NAUN Address: 0000.a6e0.11a6, NAUN drop: 00000000 Last source: 0000.a6e0.11a6, Last poll: 0000.3080.6f40 Last MVID: 0006, Last attn code: 0006 Txmit priority: 0006, Auth Class: 7FFF Monitor Error: 0000, Interface Errors: FFFF Correlator: 0000, Soft Error Timer: 00C8 Local Ring: 0000, Ring Status: 0000 Beacon rcv type: 0000, Beacon txmit type: 0000
Use the show dhcp command to display the current DHCP settings on the communication server's asynchronous interfaces.
show dhcp [interface number]
interface number | (Optional) Interface number. |
Privileged EXEC
If you omit the optional argument, the show dhcp command displays information about all interfaces.
CS# show dhcp server
IP address pooling for Point to Point clients is: DHCP Proxy Client
DHCP Proxy Client Status:
DHCP server: ANY (255.255.255.255)
Leases: 0
Offers: 0 Requests: 0 Acks: 0 Naks: 0
Declines: 0 Releases: 0 Bad: 0
Table 6-13 describes the fields shown in the display.
| Field | Description |
|---|---|
Leases | Number of current leased IP addresses. |
Offers | Number of offers for an IP address sent to a proxy-client from the server. |
Requests | Number of requests for an IP address to the server. |
Acks | Number of 'acknowledge' messages sent by the server to the proxy-client. |
Naks | Number of 'not acknowledge' messages sent by the server to the proxy-client. |
Declines | Number of offers from the server that are declined by the proxy-client. |
Releases | Number of times IP addresses have been relinquished gracefully by the client. |
Bad | Number of bad packets received from wrong length, wrong field type, etc. |
ip address-pool dhcp-proxy-client
ip dhcp-server
peer default ip address pool
type unit | (Optional) Interface type. Allowed values include async, ethernet, loopback, null, serial, tokenring, and tunnel. |
number | (Optional) Interface number |
accounting | (Optional) Displays the number of packets of each protocol type that has been sent through the interface. You can show these numbers for all interfaces, or you can specify a specific type and number. |
EXEC
The show interfaces command displays statistics for the network interfaces. If you enter a show interfaces command for an interface type that has been removed from the communication server, interface statistics will be displayed accompanied by the following text: "Hardware has been removed."
You will use the show interfaces command frequently while configuring and monitoring communication servers. The various forms of the show interfaces commands are described in detail in the sections immediately following this command.
To display the number of packets of each protocol type that have been sent through all configured interfaces, use the show interfaces accounting EXEC command. When you use the accounting option, only the accounting statistics are displayed.
Table 6-14 lists the protocols for which per-packet accounting information is kept.
| Protocol | Notes |
|---|---|
ARP | For IP, Frame Relay, SMDS. |
DEC MOP | The communication servers use MOP packets to advertise their existence to DEC machines that use the MOP protocol. A communication server periodically broadcasts MOP packets to identify itself as a MOP host. This results in MOP packets being counted. |
HP Probe | — |
IP | — |
Lan Manager | LAN Network Manager and IBM Network Manager. |
IPX | — |
The following is sample output from the show interfaces command. Because your display will depend on the type and number of interface cards in your communication server, only a portion of the display is shown.
cs# show interfaces
Ethernet 0 is up, line protocol is up
Hardware is MCI Ethernet, address is 0000.0c00.750c (bia 0000.0c00.750c)
Internet address is 131.108.28.8, subnet mask is 255.255.255.0
MTU 1500 bytes, BW 10000 Kbit, DLY 100000 usec, rely 255/255, load 1/255
Encapsulation ARPA, loopback not set, keepalive set (10 sec)
ARP type: ARPA, ARP Timeout 4:00:00
Last input 0:00:00, output 0:00:00, output hang never
Last clearing of "show interface" counters 0:00:00
Output queue 0/40, 0 drops; input queue 0/75, 0 drops
Five minute input rate 0 bits/sec, 0 packets/sec
Five minute output rate 2000 bits/sec, 4 packets/sec
1127576 packets input, 447251251 bytes, 0 no buffer
Received 354125 broadcasts, 0 runts, 0 giants
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
5332142 packets output, 496316039 bytes, 0 underruns
0 output errors, 432 collisions, 0 interface resets, 0 restarts
---More---
The following is sample output from the show interfaces accounting command:
cs# show interfaces accounting
Ethernet0
Protocol Pkts In Chars In Pkts Out Chars Out
IP 873171 735923409 34624 9644258
Novell 163849 12361626 57143 4272468
DEC MOP 0 0 1 77
ARP 69618 4177080 1529 91740
When the output indicates an interface is "disabled," the communication server has received excessive errors (over 5000 in a keepalive period).
Use the show interfaces async EXEC command to display information about the serial interface.
show interfaces async [unit] [accounting]
unit | (Optional) Must be 1. |
accounting | (Optional) Displays the number of packets of each protocol type that have been sent through the interface. |
EXEC
The following is sample output from the show interfaces async command:
cs# show interfaces async 1 Async 1 is up, line protocol is up Hardware is Async Serial Internet address is 1.0.0.1, subnet mask is 255.0.0.0 MTU 1500 bytes, BW 9 Kbit, DLY 100000 usec, rely 255/255, load 56/255 Encapsulation SLIP, keepalive set (0 sec) Last input 0:00:03, output 0:00:03, output hang never Last clearing of "show interface" counters never Output queue 0/3, 2 drops; input queue 0/0, 0 drops Five minute input rate 0 bits/sec, 1 packets/sec Five minute output rate 2000 bits/sec, 1 packets/sec 273 packets input, 13925 bytes, 0 no buffer Received 0 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 221 packets output, 41376 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets, 0 restarts 0 carrier transitions
The following is a sample display from the show interfaces async accounting command:
cs# show interfaces async 0 accounting Async 0 Protocol Pkts In Chars In Pkts Out Chars Out IP 7344 4787842 1803 1535774 DEC MOP 0 0 127 9779 ARP 7 420 39 2340
The show line and show slip commands can also be useful in monitoring asynchronous interfaces.
Table 6-15 describes the fields shown in the two sample displays.
| Field | Description |
|---|---|
Async... is {up | down | | Indicates whether the interface hardware is currently active (whether carrier detect is present) and if it has been taken down by an administrator. |
line protocol is {up | down | | Indicates whether the software processes that handle the line protocol think the line is usable (that is, whether keepalives are successful). |
Hardware is | Hardware type. |
Internet address is | IP address. |
Subnet mask is | Subnet mask. |
MTU | Maximum transmission unit of the interface. |
BW | Bandwidth of the interface in kilobits per second. |
DLY | Delay of the interface in microseconds. |
rely | Reliability of the interface as a fraction of 255 (255/255 is 100% reliability), calculated as an exponential average over five minutes. |
load | Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over five minutes. The calculation uses the value from the bandwidth interface configuration command. |
Encapsulation | Encapsulation method assigned to interface. |
keepalive | Indicates whether keepalives are set or not. |
Last input | Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface failed. |
output | The number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface. |
output hang | Number of hours, minutes, and seconds (or never) since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed. |
Last clearing | The time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) shown in this report were last reset to zero. Note that variables that might affect routing (for example, load and reliability) are not cleared when the counters are cleared. |
Output queue, drops | Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped due to a full queue. |
Five minute input rate, | Average number of bits and packets transmitted per second in the last five minutes. |
packets input | Total number of error-free packets received by the system. |
bytes | Total number of bytes, including data and MAC encapsulation, in the error free packets received by the system. |
no buffer |