Cisco IOS Interface and Hardware Component Command Reference, Release 12.3
Interface and Hardware Component Commands: A through C

Table Of Contents

Interface and Hardware Component Commands

alarm-interface

aps authenticate

aps force

aps group

aps lockout

aps manual

aps protect

aps revert

aps timers

aps unidirectional

aps working

atm sonet

au-3

au-4 tug-3

aug mapping

auto-polarity

b2 sd-ber

b2 sf-ber

bandwidth (interface)

bert abort

bert controller

bert pattern (T1/E1)

bert pattern (T3/E3)

bert profile

cablelength

cablelength (E1 controller)

cablelength long

cablelength short

carrier-delay

channel-group (EtherChannel)

channel-group (Fast EtherChannel)

channelized

clear aim

clear controller

clear counters

clear dsip tracing

clear hub

clear hub counters

clear interface fastethernet

clear interface serial

clear interface

clear ipc statistics

clear service-module serial

clock rate

clock rate line

clock rate network-clock

clock source (controller)

clock source (CT3IP)

clock source (interface)

clock source (J1 controller)

clock source (SONET controller)

clock source (T1/E1 controller)

clock source (T1/E1 interface)

clock source (T3/E3 controller)

cmt connect

cmt disconnect

compress

compress mppc

compress stac caim

controller

controller e3

controller sonet

controller t3

crc

crc4

crc bits 5

cut-through


Interface and Hardware Component Commands


alarm-interface

To enter alarm-interface mode and configure the alarm interface controller (AIC), use the alarm-interface command in global configuration mode. To leave alarm interface mode, use the exit command.

alarm-interface slot-number

Syntax Description

slot-number

Number of the port in which the AIC is installed.


Defaults

No default behavior or values

Command Modes

Global configuration

Command History

Release
Modification

12.2(2)XG

This command was introduced for the Cisco 2600 series and the Cisco 3600 series.

12.2(8)T

This command was integrated into Cisco IOS Release 12.2(8)T.


Examples

The following examples show how the alarm-interface command is used in conjunction with the ip address and the reset commands:

Router(config)# alarm-interface 5
Router(config-aic)# ip address 10.2.130.105

A change in the AIC IP configuration might not take effect until the next time the card is started. Use the reset command to restart the card, as in the following example:

Router(config-aic)# reset
Alarm Interface Card in slot 5 restarted

Router(config-aic)# end

Related Commands

Command
Description

ip address

Sets a primary or secondary IP address for an interface.

reset

Resets the AIC CPU.


aps authenticate

To enable authentication and specify the string that must be present to accept any packet on the out-of-band (OOB) communications channel on a Packet-over-SONET (POS) interface, use the aps authenticate command in interface configuration mode. To disable authentication, use the no form of this command.

aps authenticate string

no aps authenticate

Syntax Description

string

Text that must be present to accept the packet on a protected or working interface. A maximum of eight alphanumeric characters are accepted.


Defaults

Authentication is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps authenticate command to ensure that only valid packets are accepted on the OOB communications channel.

The aps authenticate command must be configured on both the working and protect interfaces.

Examples

The following example shows how to enable authentication on POS interface 0 in slot 4:

Router# configure terminal
Router(config)# interface pos 4/0/0
Router(config-if)# aps working 1
Router(config-if)# aps authenticate sanjose
Router(config-if)# end

Related Commands

Command
Description

aps protect

Enables a POS interface as a protect interface.

aps working

Configures a POS interface as a working interface.


aps force

To manually switch the specified circuit to a protect interface, unless a request of equal or higher priority is in effect, use the aps force command in interface configuration mode. To cancel the switch, use the no form of this command.

aps force circuit-number

no aps force circuit-number

Syntax Description

circuit-number

Number of the circuit to switch to the protect interface.


Defaults

No circuit is switched.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps force command to manually switch the interface to a protect interface when you are not using the aps revert command. For example, if you need to change the fiber connection, you can manually force the working interface to switch to the protect interface.

In a one-plus-one (1+1) configuration only, you can use the aps force 0 command to force traffic from the protect interface back onto the working interface.

The aps force command has a higher priority than any of the signal failures or the aps manual command.

The aps force command is configured only on protect interfaces.

Examples

The following example shows how to force the circuit on POS interface 0 in slot 3 (a protect interface) back onto a working interface:

Router# configure terminal
Router(config)# interface pos 3/0/0
Router(config-if)# aps protect 10/30/1/1
Router(config-if)# aps force 1
Router(config-if)# end

Related Commands

Command
Description

aps manual

Manually switches a circuit to a protect interface.

aps protect

Enables a POS interface as a protect interface.

aps working

Configures a POS interface as a working interface.


aps group

To allow more than one protect and working interface to be supported on a router, use the aps group command in interface configuration mode. To remove a group, use the no form of this command.

aps group group-number

no aps group group-number

Syntax Description

group-number

Number of the group. Default is 0.


Defaults

No groups exist.


Note 0 is a valid group number.


Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps group command to specify more than one working and protect interfaces on a router, for example, working channel for group 0 and protect channel for group 1 on one router, and working channel for group 1 and protect channel for group 0 on another router.

The default group number is 0. The aps group 0 command does not imply that no groups exist.

The aps group command must be configured on both the protect and working interfaces.

Examples

The following example shows hw to configure two working/protect interface pairs. Working interface (3/0/0) is configured in group 10 (the protect interface for this working interface is configured on another router), and protect interface (2/0/1) is configured in group 20.

Router# configure terminal
Router(config)# interface ethernet 0/0
Router(config-if)# ip address 10.7.7.6 255.255.255.0
Router(config-if)# exit
Router(config)# interface pos 3/0/0
Router(config-if)# aps group 10
Router(config-if)# aps working 1
Router(config-if)# exit
Router(config)# interface pos 2/0/1
Router(config-if)# aps group 20
Router(config-if)# aps protect 1 10.7.7.7
Router(config-if)# end

On the second router, protect interface (4/0/0) is configured in group 10, and working interface (5/0/0) is configured in group 20 (the protect interface for this working interface is configured on another router).

Router(config)# interface ethernet 0/0
Router(config-if)# ip address 10.7.7.7 255.255.255.0
Router(config-if)# exit
Router(config)# interface pos 4/0/0
Router(config-if)# aps group 10
Router(config-if)# aps protect 1 10.7.7.6
Router(config-if)# exit
Router(config)# interface pos 5/0/0
Router(config-if)# aps group 20
Router(config-if)# aps working 1
Router(config-if)# end

Related Commands

Command
Description

aps protect

Enables a POS interface as a protect interface.

aps working

Configures a POS interface as a working interface.


aps lockout

To prevent a working interface from switching to a protect interface, use the aps lockout command in interface configuration mode. To remove the lockout, use the no form of this command.

aps lockout circuit-number

no aps lockout circuit-number

Syntax Description

circuit-number

Number of the circuit to lock out.


Defaults

No lockout exists.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

The aps lockout command is configured only on protect interfaces.

Examples

The following example shows how to lock out POS interface 3/0/0 (that is, prevents the circuit from switching to a protect interface if the working circuit becomes unavailable):

Router# configure terminal
Router(config)# interface pos 3/0/0
Router(config-if)# aps protect 1 10.7.7.7
Router(config-if)# aps lockout 1
Router(config-if)# end

Related Commands

Command
Description

aps protect

Enables a POS interface as a protect interface.

aps working

Configures a POS interface as a working interface.


aps manual

To manually switch a circuit to a protect interface, use the aps manual command in interface configuration mode. To cancel the switch, use the no form of this command.

aps manual circuit-number

no aps manual circuit-number

Syntax Description

circuit-number

Number of the circuit to switch to a protect interface.


Defaults

No circuit is switched.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps manual command to manually switch the interface to a protect interface. For example, you can use this feature when you need to perform maintenance on the working channel. If a protection switch is already up, you can also use the aps manual command to revert the communication link back to the working interface before the wait to restore (WTR) time has expired. The WTR time period is set by the aps revert command.

In a one-plus-one (1+1) configuration only, you can use the aps manual 0 command to force traffic from the protect interface back onto the working interface.

The aps manual command is a lower priority than any of the signal failures or the aps force command.

Examples

The following example shows how to force the circuit on POS interface 0 in slot 3 (a working interface) back onto the protect interface:

Router# configure terminal
Router(config)# interface pos 3/0/0
Router(config-if)# aps working 1
Router(config-if)# aps manual 1
Router(config-if)# end

Related Commands

Command
Description

aps force

Manually switches the specified circuit to a protect interface, unless a request of equal or higher priority is in effect.

aps protect

Enables a POS interface as a protect interface.

aps revert

Enables automatic switchover from the protect interface to the working interface after the working interface becomes available.

aps working

Configures a POS interface as a working interface.


aps protect

To enable a POS interface as a protect interface, use the aps protect command in interface configuration mode. To remove the POS interface as a protect interface, use the no form of this command.

aps protect circuit-number ip-address

no aps protect circuit-number ip-address

Syntax Description

circuit-number

Number of the circuit to enable as a protect interface.

ip-address

IP address of the router that has the working POS interface.


Defaults

No circuit is protected.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps protect command to configure the POS interface used by a working interface if the working interface becomes unavailable because of a router failure, degradation or loss of channel signal, or manual intervention.


Caution Configure the working interface before configuring the protect interface to keep the protect interface from becoming the active circuit and disabling the working circuit when it is finally discovered.

Examples

The following example shows how to configure circuit 1 on POS interface 5/0/0 as a protect interface for the working interface on the router with the IP address of 10.7.7.7. For information on how to configure the working interface, refer to the aps working command.

Router# configure terminal
Router(config)# interface pos 5/0/0
Router(config-if)# aps protect 1 10.7.7.7
Router(config-if)# end

Related Commands

Command
Description

aps working

Configures a POS interface as a working interface.


aps revert

To enable automatic switchover from the protect interface to the working interface after the working interface becomes available, use the aps revert command in interface configuration mode. To disable automatic switchover, use the no form of this command.

aps revert minutes

no aps revert

Syntax Description

minutes

Number of minutes until the circuit is switched back to the working interface after the working interface is available.


Defaults

Automatic switchover is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps revert command to return the circuit to the working interface when it becomes available.

The aps revert command is configured only on protect interfaces.

Examples

The following example shows how to enable circuit 1 on POS interface 5/0/0 to revert to the working interface after the working interface has been available for 3 minutes:

Router# configure terminal
Router(config)# interface pos 5/0/0
Router(config-if)# aps protect 1 10.7.7.7
Router(config-if)# aps revert 3
Router(config-if)# end

Related Commands

Command
Description

aps protect

Enables a POS interface as a protect interface.


aps timers

To change the time between hello packets and the time before the protect interface process declares a working interface router to be down, use the aps timers command in interface configuration mode. To return to the default timers, use the no form of this command.

aps timers seconds1 seconds2

no aps timers

Syntax Description

seconds1

Number of seconds to wait before sending a hello packet (hello timer). Default is 1.

seconds2

Number of seconds to wait to receive a response from a hello packet before the interface is declared down (hold timer). Default is 3.


Defaults

Hello time is 1 second
Hold time is 3 seconds.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps timers command to control the time between an automatic switchover from the protect interface to the working interface after the working interface becomes available.

Normally, the hold time is greater than or equal to three times the hello time.

The aps timers command is configured only on protect interfaces.

Examples

The following example shows how to specify a hello time of 2 seconds and a hold time of 6 seconds on circuit 1 on POS interface 5/0/0:

Router# configure terminal
Router(config)# interface pos 5/0/0
Router(config-if)# aps working 1
Router(config-if)# aps timers 2 6
Router(config-if)# end

aps unidirectional

To configure a protect interface for unidirectional mode, use the aps unidirectional command in interface configuration mode. To return to the default, bidirectional mode, use the no form of this command.

aps unidirectional

no aps unidirectional

Syntax Description

This command has no arguments or keywords.

Defaults

Bidirectional mode

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

Use the aps unidirectional command when you must interoperate with SONET network equipment, Add Drop Multiplexor(s) (ADMs) that supports unidirectional mode.


Note We recommend bidirectional mode when it is supported by the interconnecting SONET equipment. When the protect interface is configured as unidirectional, the working and protect interfaces must cooperate to switch the transmit and receive SONET channel in a bidirectional fashion. This happens automatically when the SONET network equipment is in bidirectional mode.


The aps unidirectional command is configured only on protect interfaces.

Examples

The following example shows how to configure POS interface 3/0/0 for unidirectional mode:

Router# configure terminal
Router(config)# interface pos 3/0/0
Router(config-if)# aps unidirectional
Router(config-if)# aps protect 1 10.7.7.7
Router(config-if)# end

aps working

To configure a Packet over SONET (POS) interface as a working interface, use the aps working command in interface configuration mode. To remove the protect option from the POS interface, use the no form of this command.

aps working circuit-number

no aps working circuit-number

Syntax Description

circuit-number

Circuit number associated with this working interface.


Defaults

No circuit is configured as working.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.


Usage Guidelines

When a working interface becomes unavailable because of a router failure, degradation or loss of channel signal, or manual intervention, the circuit is switched to the protect interface to maintain the connection.

To enable the circuit on the protect interface to switch back to the working interface after the working interface becomes available again, use the aps revert command in interface configuration mode.


Caution Configure the working interface before configuring the protect interface to keep the protect interface from becoming the active circuit and disabling the working circuit when it is finally discovered.

Examples

The following example shows how to configure POS interface 0 in slot 4 as a working interface. For information on how to configure the protect interface, refer to the aps protect command.

Router# configure terminal
Router(config)# interface pos 4/0/0
Router(config-if)# aps working 1
Router(config-if)# end

Related Commands

Command
Description

aps protect

Enables a POS interface as a protect interface.

aps revert

Enables automatic switchover from the protect interface to the working interface after the working interface becomes available.


atm sonet

To set the mode of operation and thus control the type of the ATM cell used for cell-rate decoupling on the SONET physical layer interface module (PLIM), use the atm sonet command in interface configuration mode. To restore the default Synchronous Transport Signal level 12, concatenated (STS-12c) operation, use the no form of this command.

atm sonet [stm-4]

no atm sonet [stm-4]

Syntax Description

stm-4

(Optional) Synchronous Digital Hierarchy/Synchronous Transport Signal level 4 (SDH/STM-4) operation (ITU-T specification).


Defaults

STS-12c

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CC

This command was introduced.

11.2 GS

The stm-4 keyword was added.


Usage Guidelines

Use STM-4 in applications in which SDH framing is required.

Use the default (STS-12c) in applications in which the ATM switch requires "unassigned cells" for rate adaptation. An unassigned cell contains 32 zeros.

Examples

The following example shows how to set the mode of operation to SONET STM-4 on ATM interface 3/0:

Router(config)# interface atm 3/0
Router(config-if)# atm sonet stm-4
Router(config-if)# end

au-3

To configure a particular Administrative Unit type 3 (AU-3) of an E1 line that has been mapped to an AU-3, use the au-3 command in controller configuration mode.

au-3 au-3-number

Syntax Description

au-3-number

Number in the range from 1 to 3.


Defaults

No default behavior or values

Command Modes

Controller configuration

Command History

Release
Modification

12.0(14)S

This command was introduced.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Usage Guidelines

An administrative unit group (AUG) of an STM-1 can be derived from either AU-3s or an AU-4. Use the aug mapping au-3 configuration controller command to map the AUG to an AU-3 with the following muxing/alignment/mapping:

C-12 <--> VC-12 <--> TU-12 <--> TUG-2 <--> VC-3 <--> AU-3 <--> AUG

Configuring the au-3 command enables you to enter configuration controller au3 command mode and creates a serial interface with the following name format:

slot/port-adapter/port.au-3-number/tug-2-number/e1-number

The aug mapping au-3 and au-3 commands are available only when SDH framing is configured.

Examples

The following example shows how to configure AUG mapping to be derived from an AU-3 and selects AU-3 3 to configure as a serial interface:

Router(config)# controller sonet 2/0/0
Router(config-controller)# aug mapping au-3
Router(config-ctrlr-au3)# au-3 3

Related Commands

Command
Description

au-4 tug-3

Specifies a TUG-3 for configuration.

aug mapping

Configures the AUG mapping mode of the PA-MC-STM-1 to AU-3.


au-4 tug-3

To specify the Administrative Unit type 4 (AU-4) and Tributary Unit group type 3 (TUG-3) number of an E1 line that has been mapped to an AU-4, use the au-4 tug-3 command in controller configuration mode.

au-4 au-4-number tug-3 tug-3-number

Syntax Description

au-4-number

Number in the range from 1 to N where N is the STM level. Default is 1.

tug-3-number

Number in the range from 1 to 3.


Defaults

Default au-4-number value for STM-1 card is 1.

Command Modes

Controller configuration

Command History

Release
Modification

12.0(14)S

This command was introduced.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Usage Guidelines

An AUG of an STM-1 can be derived from either AU-3s or an AU-4. Use the aug mapping au-4 configuration controller command to map the AUG to an TUG-3 with the following muxing/alignment/mapping:

C-12 <--> VC-12 <--> TU-12< --> TUG-2 <--> TUG-3 <--> VC-4 <--> AU-4 <--> AUG

Configuring the au-4 command enables you to enter configuration controller tug3 command mode and creates a serial interface with the following name format:

slot/port-adapter/port.au-4-number/tug-2-number/e1-number

The aug mapping au-4 and au-4 tug-3 commands are available only when SDH framing is configured.

Examples

The following example shows how to configure AUG mapping to be derived from a TUG-3 and selects TUG-3 1 of AU-4 1:

Router(config)# controller sonet 2/0/0
Router(config-controller)# aug mapping au-4
Router(config-ctrlr-tug3)# au-4 1 tug-3 1

Related Commands

Command
Description

au-3

Specifies an AU-3 for configuration.

aug mapping

Configures the AUG mapping mode.


aug mapping

To configure administrative unit group (AUG) mapping when SDH framing is selected, use the aug mapping command in controller configuration mode.

aug mapping {au-3 | au-4}

Syntax Description

au-3

Specifies use of three paths—a path is known as an Administrative Unit (AU)—consisting of seven TUG-2s (Tributary Unit group type 2). Each TUG-2 consists of three virtual containers (VC-12s), which carry E1 lines resulting in 21 E1 lines within one AU-3 path.

au-4

Specifies use of one path consisting of three TUG-3 types. Each TUG-3 consists of seven TUG-2s, resulting in a total of 63 E1 lines within one AU-4 path. This is the default.


Defaults

au-4

Command Modes

Controller configuration

Command History

Release
Modification

12.0(14)S

This command was introduced.

12.0(17)S

Support for the two-port STM-1/OC-3 channelized E1/T1 line card was added.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Usage Guidelines

In SDH, there are two possible mapping/multiplexing schemes for most payload types: ANSI and ETSI.

In ANSI mapping, the Low Order payloads are aggregated into a VC-3 High Order Path. An AU pointer is added to the VC-3 to create an AU-3. Three such AU-3s are then synchronously multiplexed into an AUG. The multiplexing scheme is as follows:

... VC-3 <-> AU-3 (x3) <-> AUG <-> STM-1

SDH ANSI mapping is very similar to the SONET frame structure.

In ETSI mapping, the Low Order payloads are aggregated into a VC-4 High Order Path. An AU pointer is added to the VC-4 to create an AU-4 (Administrative Unit type 4). One AU-4 is "multiplexed" into an AUG (AU group), which is to say, the AUG is, in fact, equivalent to an AU-4. The multiplexing scheme is as follows:

... TUG-3 (x3) <-> VC-4 <-> AU-4 (x1) <-> STM-1

This command is available only when SDH framing is configured.

This command does not have a no form because data must flow using one of the two mapping/multiplexing schemes.

Examples

The following example shows how to configure AU-3 mapping for the STM-1 trunk card:

Router(config)# controller sonet 1/0
Router(config-controller)# aug mapping au-3

auto-polarity

To enable automatic receiver polarity reversal on a hub port connected to an Ethernet interface of a Cisco 2505 or Cisco 2507 router, use the auto-polarity command in hub configuration mode. To disable this function, use the no form of this command.

auto-polarity

no auto-polarity

Syntax Description

This command has no arguments or keywords.

Defaults

Enabled

Command Modes

Hub configuration

Command History

Release
Modification

10.3

This command was introduced.


Usage Guidelines

This command applies to a port on an Ethernet hub only.

Examples

The following example shows how to enable automatic receiver polarity reversal on hub 0, ports 1 through 3:

Router(config)# hub ethernet 0 1 3
Router(config-hub)# auto-polarity

Related Commands

Command
Description

hub

Enables and configures a port on an Ethernet hub of a Cisco 2505 or Cisco 2507 router.


b2 sd-ber

To set the signal degrade bit-error rate (BER) threshold values, use the b2 sd-ber command in controller configuration mode. To return to the default setting, use the no form of this command.

b2 sd-ber rate

no b2 sd-ber

Syntax Description

rate

Bit-error rate from 3 to 9 (10-n). The value of 9 represents better quality, and the value of 3 represents lower quality. The default is 6.


Defaults

rate: 6

Command Modes

Controller configuration

Command History

Release
Modification

12.2(15)T

This command was introduced.


Usage Guidelines

Use this command to configure the threshold for degradation of quality of signal with b2 errors.

Examples

The following example shows how to configure a signal degrade BER threshold value of 7 on the SONET controller:

Router(config)# controller sonet 1/0
Router(config-controller)# b2 sd-ber 7

Related Commands

Command
Description

show controllers sonet

Displays information about the SONET controllers.


b2 sf-ber

To set the signal failure bit-error rate (BER) threshold values, use the b2 sf-ber command in controller configuration mode. To return to the default setting, use the no form of this command.

b2 sf-ber rate

no b2 sf-ber rate

Syntax Description

rate

Bit-error rate from 3 to 9 (10-n). The value of 9 represents better quality, and the value of 3 represents lower quality. The default is 3.


Defaults

rate: 3

Command Modes

Controller configuration

Command History

Release
Modification

12.2(15)T

This command was introduced.


Usage Guidelines

Use this command to configure the threshold for failure of quality of signal with b2 errors. The value of 9 represents better quality and the value of 3 represents lower quality.

Examples

The following example shows how to configure a signal failure BER threshold value of 7 on the SONET controller:

Router(config)# controller sonet 1/0
Router(config-controller)# b2 sf-ber 7

Related Commands

Command
Description

show controllers sonet

Displays information about the SONET controllers.


bandwidth (interface)

To set and communicate the current bandwidth value for an interface to higher-level protocols, use the bandwidth command in interface configuration mode. To restore the default values, use the no form of this command.

bandwidth {kbps | inherit [kbps]}

no bandwidth {kbps | inherit [kbps]}

Syntax Description

kbps

Intended bandwidth, in kilobits per second. For a full bandwidth DS3 line, enter the value 44736.

inherit

(Optional) Inherited bandwidth. Specifies how a subinterface inherits the bandwidth of its main interface.


Defaults

Default bandwidth values are set during startup; the bandwidth values can be displayed using the show interfaces EXEC command.

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.

12.2

The inherit keyword was added.


Usage Guidelines

Bandwidth Information

The bandwidth command sets an informational parameter to communicate only the current bandwidth to the higher-level protocols; you cannot adjust the actual bandwidth of an interface using this command.


Note This is a routing parameter only; it does not affect the physical interface.


Changing Bandwidth

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.

Bandwidth Inheritance

Before the introduction of the bandwidth inherit command option, when the bandwidth value was changed on the main interface, existing subinterfaces did not inherit the bandwidth value from the main interface. If the subinterface was created before the bandwidth was changed on the main interface, then the subinterface would receive the default bandwidth of the main interface, not the configured bandwidth. Additionally, if the router was subsequently reloaded, the bandwidth of the subinterface would then change to the bandwidth configured on the main interface.

The bandwidth inherit command controls how a subinterface inherits the bandwidth of its main interface. This functionality eliminates the inconsistencies related to whether or not the router has been reloaded and what the order was in entering the commands.

The no bandwidth inherit command enables all subinterfaces to inherit the default bandwidth of the main interface, regardless of the configured bandwidth. If a bandwidth is not configured on a subinterface, and you use the bandwidth inherit command, all subinterfaces will inherit the current bandwidth of the main interface. If you configure a new bandwidth on the main interface, all subinterfaces will use this new value.

If you do not configure a bandwidth on the subinterface and you configure the bandwidth inherit kbps command on the main interface, the subinterfaces will inherit the specified bandwidth.

In all cases, if an interface has an explicit bandwidth setting configured, then that interface will use that setting, regardless of whether or not the bandwidth inheritance setting is in effect.

Examples

The following example shows how to set the full bandwidth for DS3 transmissions:

Router(config)# interface serial 0
Router(config-if)# bandwidth 44736

Related Commands

Command
Description

show interfaces

Displays statistics for all interfaces configured on the router.


bert abort

To end a bit error rate testing session, use the bert abort command in privileged EXEC mode.

bert abort

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(2)XD

This command was introduced.

12.0(3)T

This command was integrated into Cisco IOS Release 12.0(3)T.


Usage Guidelines

Use the bert abort command to cancel bit error rate testing on each port of the Cisco AS5300 router.

The bit error rate test (BERT) feature enables you to test the quality of the connected PRI links by direct comparison of a pseudorandom or repetitive test pattern with an identical locally generated test pattern.

Examples

The following is sample output from the bert abort command when no bit error rate test is running:

Router# bert abort
Router#
17:53:33: There is no BERT Test running ....

The following is sample output from the bert abort command when a bit error rate test is running:

Router# bert abort
Do you really want to abort the current BERT [confirm] Y

17:56:56: %BERT-6-BERT_RESULTS: Controller T1 0 Profile default : The Test was
aborted by User

Related Commands

Command
Description

bert controller

Starts a bit error rate test for a particular port.

bert pattern (T1/E1)

Sets up various bit error rate testing profiles.


bert controller

To start a bit error rate test (BERT) for a particular port, use the bert controller command in privileged EXEC mode.

bert controller [type-controller] {last-controller | profile [number | default]}

Syntax Description

type-controller

(Optional) Type of controller being tested. Use either T1 or E1 depending on the type of facility.

last-controller

(Optional) Last controller number. The valid range is from 0 to 7.

profile

Sets the profile numbers for the bit error rate test.

number

(Optional) Numbers of the test profiles to use. The valid range is from 0 to 15. The default is 0.

default

(Optional) Executes the default bit error rate test (0).


Defaults

number: 0

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(2)XD

This command was introduced.

12.0(3)T

This command was integrated into Cisco IOS Release 12.0(3)T.


Usage Guidelines

Use the bert controller command to start a bit error rate test for a particular port on a Cisco AS5300 router.

Quality Testing

The BERT feature enables you to test the quality of the connected PRI links by direct comparison of a pseudorandom or repetitive test pattern with an identical locally generated test pattern.

E1 Controllers

The E1 controller cannot be set in loopback mode from the Cisco AS5300. For the bert controller command to work correctly with the E1 controller, the controller must be configured as a channel group or channel-associated signaling (CAS) and the line must be configured as a remote loop from the switch side of the link.

Examples

The following is sample output from the bert controller command:

Router# bert controller T1 profile default

Press <Return> to start the BERT [confirm] Y

17:55:34: %BERT-6-BERT_START: Starting BERT on Interface 0 with Profile default
Data in current interval (10 seconds elapsed):
     0 Line Code Violations, 0 Path Code Violations
     0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
     0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Table 1 describes the significant fields shown in the display.

Table 1 bert controller Field Descriptions 

Field
Description

Data in Current Interval

Shows the current accumulation period, which rolls into the 24-hour accumulation every 15 minutes. As the latest 15-minute accumulation period enters the buffer, the oldest 15-minute period is deleted. The accumulation period is from 1 to 900 seconds.

Line Code Violations

For alternate mark inversion (AMI)-coded signals, a line code violation is a bipolar violation (BPV) occurrence. Indicates the occurrence of either a BPV or an excessive zeros (EXZ) error event.

Path Code Violations

When super frame (SF) (D4) framing is used, a path code violation is a framing error. When extended super frame (ESF) framing is used, a path code violation is a cyclic redundancy check type 6 (CRC-6) error. Indicates a frame-synchronization bit error in the D4 and E1-non-CRC formats, or a CRC error in the ESF and E1-CRC formats.

Slip Secs

Indicates the replication or deletion of the payload bits of a DS1 frame. A slip may be indicated when there is a difference between the timing of a synchronous receiving terminal and the received signal.

Fr Loss Secs

Seconds during which the framing pattern has been lost. Indicates the number of seconds for which an Out-of-Frame error is detected.

Line Err Secs

A line error second (LES) is a second in which one or more line code violation (LCV or CV-L) errors are detected.

Degraded Mins

A degraded minute is one in which the estimated error rate exceeds 1-6 but does not exceed 1-3.

Errored Secs

In extended superframe (ESF) and E1-CRC links, an errored second is a second in which one of the following is detected: one or more path code violations; one or more Out-of-Frame defects; one or more controlled slip events; an alarm indication signal (AIS) defect.

For D4 and E1-non-CRC links, the presence of bipolar violations also triggers an errored second.

Bursty Err Secs

Second with fewer than 320 and more than 1 path code violation error, no severely errored frame defects, and no detected incoming AIS defects. Controlled slips are not included in this parameter.

Severely Err Secs

For ESF signals, a second with one of the following errors: 320 or more path code violation errors; one or more Out-of-Frame defects; a detected AIS defect.

For E1-CRC signals, a second with one of the following errors: 832 or more path code violation errors; one or more Out-of-Frame defects.

For E1-non-CRC signals, a second with 2048 or more line code violations.

For D4 signals, a count of 1-second intervals with framing errors, or an Out-of-Frame defect, or 1544 line code violations.

Unavail Secs

Count for every second in which an unavailable signal state occurs. This term is used by new standards in place of failed seconds (FS).


Related Commands

Command
Description

bert abort

Aborts a bit error rate testing session.

bert pattern (T1/E1)

Sets up various bit error rate testing profiles.


bert pattern (T1/E1)

To enable a bit error rate test (BERT) pattern on a T1 or E1 line, use the bert pattern command in controller configuration mode. To disable a BER test pattern, use the no form of this command.

bert pattern {2^23 | 2^20 | 2^20-QRSS | 2^15 | 2^11 | 1s | 0s | alt-0-1} interval time

no bert pattern {2^23 | 2^20 | 2^20-QRSS | 2^15 | 2^11 | 1s | 0s | alt-0-1} interval time

Syntax Description

2^23

Invokes a pseudorandom 0.151 test pattern that is 8,388,607 bits in length.

2^20

Invokes a pseudorandom 0.153 test pattern that is 1,048,575 bits in length.

2^20-QRSS

Invokes a pseudorandom quasi-random signal sequence (QRSS) 0.153 test pattern that is 1,048,575 bits in length.

2^15

Invokes a pseudorandom 0.151 test pattern that is 32,768 bits in length.

2^11

Invokes a pseudorandom test pattern that is 2,048 bits in length.

1s

Invokes a repeating pattern of ones (...111...).

0s

Invokes a repeating pattern of zeros (...000...).

alt-0-1

Invokes a repeating pattern of alternating zeros and ones (...01010...).

interval time

Specifies the duration (in minutes) of the BER test. The interval can be a value from 1 to 14400. There is no default.


Defaults

Disabled

Command Modes

Controller configuration

Command History

Release
Modification

11.1CC

This command was introduced.

12.0(5)XE

This command was enhanced as an ATM interface configuration command.

12.0(7)XE1

This command was implemented on Cisco 7100 series routers.

12.1(5)T

This command was integrated into Cisco IOS Release 12.1(5)T.


Usage Guidelines

BER testing is supported on each of the T1 or E1 links, is done only over an unframed T1 or E1 signal, and is run on only one port at a time.

To view the BER test results, use the show controllers atm EXEC command. The BERT results include the following information:

Type of test pattern selected

Status of the test

Interval selected

Time remaining on the BER test

Total bit errors

Total bits received

When the T1 or E1 line has a BER test running, the line state is DOWN and the status field shows the current/last result of the test.

The bert pattern command is not written to NVRAM because this command is only used to test the T1 or E1 line for a short predefined interval, and to avoid accidentally saving the command.

Examples

The following example shows how to run a BERT pattern of all zeros on a Cisco 7200 series router for 30 minutes on the T1 controller in slot 1:

Router(config)# controller T1 1/0
Router(config-if)# bert pattern 0s interval 30

Related Commands

Command
Description

show controllers atm

Displays information about T1/E1 links in Cisco 7100 series routers, Cisco 7200 series routers, and Cisco 7500 series routers.


bert pattern (T3/E3)

To enable a bit error rate test (BERT) pattern on a T3 or E3 controller, use the bert pattern command in controller configuration mode. To disable a BER test pattern, use the no form of this command.

bert pattern {2^23 | 2^20 | 2^15 | 1s | 0s | alt-0-1} interval time

no bert pattern

Syntax Description

2^23

Invokes a pseudorandom 0.151 test pattern that is 8,388,607 bits in length.

2^20

Invokes a pseudorandom 0.153 test pattern that is 1,048,575 bits in length.

2^15

Invokes a pseudorandom 0.151 test pattern that is 32,768 bits in length.

1s

Invokes a repeating pattern of ones (...111...).

0s

Invokes a repeating pattern of zeros (...000...).

alt-0-1

Invokes a repeating pattern of alternating zeros and ones (...01010...).

interval time

Specifies the duration (in minutes) of the BER test. The interval can be a value from 1 to 14400. There is no default.


Defaults

Disabled

Command Modes

Controller configuration

Command History

Release
Modification

11.1 CC

This command was introduced.

12.1(5)T

This command was integrated into Cisco IOS Release 12.1(5)T.

12.2(11)YT

This command was integrated into Cisco IOS Release 12.2(11)YT and implemented on the following platforms: Cisco 2650XM, Cisco 2651XM, Cisco 2691, Cisco 3660 series, Cisco 3725, and Cisco 3745 routers.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Usage Guidelines

BER testing is supported on T3/E3 links and is done only over framed T3 or E3 signals, unless E3 framing is in bypass mode.

To display the BER test results, use the show controllers t3 or show controllers e3 EXEC command. The BER test results include the following information:

Type of test pattern selected

Status of the test

Interval selected

Time remaining on the BER test

Total bit errors

Total bits received

When the T3 or E3 line has a BER test running, the line state is DOWN and the status field shows the current or last result of the test.

The bert pattern command is not written to NVRAM because this command is used only to test the T3 or E3 line for a short predefined interval, and to avoid accidentally saving the command.

Examples

The following example shows how to run a BERT pattern of all zeros for 30 minutes on the T3 controller in slot 1:

Router(config)# controller T3 1/0
Router(config-if)# bert pattern 0s interval 30

Related Commands

Command
Description

show controllers e3

Displays information about E3 controllers.

show controllers t3

Displays information about T3 controllers.


bert profile

To set up various bit error rate testing profiles, use the bert profile command in global configuration mode. To disable the particular bit error rate test (BERT) profile indicated by profile number, use the no form of this command.

bert profile number pattern pattern threshold threshold error-injection err-inj duration time

no bert profile number pattern pattern threshold threshold error-injection err-inj duration time

Syntax Description

number

BERT profile number. The valid range is from 1 to 15. This is the number assigned to a particular set of parameters. If no such profile of the same number exists in the system, a new profile is created with that number; otherwise, an existing set of parameters with that profile number is overwritten by the new profile.

pattern

Pattern that BERT will generate on the line.

pattern

0s—Repetitive pattern, all zeros.
1_in_16n repetitive pattern, 1 in 16.
1sn repetitive pattern, all ones.
211-O.152n pseudorandom pattern, 211 -1 O.152.
215-O.15n pseudorandom pattern, 215 -1 O.151.
220-O.151QRSSn pseudorandom pattern, 220 -1 O.151 QRSS. (This is the default.)
220-O.153n pseudorandom pattern, 220 -1 O.153.
3_in_24n repetitive pattern, 3 in 24.

threshold

Test failure (error) threshold that determines if the BERT on this line passed.

threshold

10^-2—Bit error rate of 10-2.
10^-3—Bit error rate of 10-3.
10^-4—Bit error rate of 10-4.
10^-5—Bit error rate of 10-5.
10^-6—Bit error rate of 10-6. (This is the default.)
10^-7—Bit error rate of 10-7.
10^-8—Bit error rate of 10-8.

error-injection

Error injection rate for bit errors injected into the BERT pattern generated by the chip.

err-inj

10^-1—Error injection of 10-1.
10^-2—Error injection of 10-2.
10^-3—Error injection of 10-3.
10^-4—Error injection of 10-4.
10^-5—Error injection of 10-5.
10^-6—Error injection of 10-6.
10^-7—Error injection of 10-7.
none—No error injection in the data pattern. (This is the default.)

duration

Duration, in minutes, for which BERT is to be executed.

time

Duration of BERT, in minutes. The valid range is from 1 to 1440. The default is 10.


Defaults

The default profile created internally by the system has parameters that cannot be changed. This profile has been defined so that you can execute BERT on a line without having to configure a new profile. The default profile is displayed when the running configuration is displayed and is not stored in NVRAM:

bert profile number pattern 220-0151QRSS threshold 10^-6 error-injection none duration 10

Command Modes

Global configuration

Command History

Release
Modification

12.0(2)XD

This command was introduced.

12.0(3)T

This command was integrated into Cisco IOS Release 12.0(3)T.


Usage Guidelines

Use the bert profile command to set up bit error rate testing profiles for the Cisco AS5300 router.

The bit error rate test (BERT) feature enables you to test the quality of the connected PRI links by direct comparison of a pseudorandom or repetitive test pattern with an identical locally generated test pattern. A BERT profile is a set of parameters related to a BERT test and is stored as part of the configuration in NVRAM. You can define up to 15 BERT profiles on the system. By setting up the BERT profiles in this way, you do not have to enter the parameters each time you want to run a BERT—just select the number of the BERT profile that you want to run.

Examples

The following example shows a configured BERT profile number 1 to have a 0s test pattern, with a 10-2 threshold, no error injection, and a duration of 125 minutes:

Router(config)# bert profile 1 pattern 0s threshold 10^-2 error-injection none duration 
125

Related Commands

Command
Description

bert abort

Aborts a bit error rate testing session.

bert controller

Starts a bit error rate test for a particular port.


cablelength

To specify the distance of the cable from the routers to the network equipment, use the cablelength command in controller configuration mode. To restore the default cable length, use the no form of this command.

cablelength feet

no cablelength

Syntax Description

feet

Number of feet in the range of 0 to 450. The default values are as follows:

224 feet for a Channelized T3 Interface Processor (CT3IP) and Clear Channel T3/E3 network module

49 feet for PA-T3 and PA-2T3 port adapters


Defaults

224 feet for a CT3IP interface processor and Clear Channel T3/E3 network module
49 feet for PA-T3 and PA-2T3 port adapters

Command Modes

Controller configuration

Command History

Release
Modification

11.1 CA

This command was introduced.

12.2(11)YT

This command was integrated into Cisco IOS Release 12.2(11)YT and implemented on the following platforms: Cisco 2650XM, Cisco 2651XM, Cisco 2691, Cisco 3660 series, Cisco 3725, and Cisco 3745 routers. Support for the Clear Channel T3/E3 network module was added.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Usage Guidelines

The default cable length of 224 feet is used by the CT3IP interface processor and the Clear Channel T3/E3 network module.

The default cable length of 49 feet is used by the PA-T3 and PA-2T3 port adapters.


Note Although you can specify a cable length from 0 to 450 feet, the hardware recognizes only two ranges: 0 to 49 and 50 to 450. For example, entering 35 feet uses the 0 to 49 range. If you later change the cable length to 40 feet, there is no change because 40 is still within the 0 to 49 range. However, if you change the cable length to 50, the 50 to 450 range is used. The actual number you enter is stored in the configuration file.


Examples

The following example shows how to set the cable length for the router to 300 feet:

Router(config)# controller t3 9/0/0
Router(config-controller)# cablelength 300

cablelength (E1 controller)

To fine-tune the pulse of a signal at the receiver for an E1 cable on a Cisco AS5300 or Cisco AS5400, use the cablelength command in controller configuration mode. To restore the default receiver sensitivity, use the no form of this command.

cablelength {custom gain-value [squelch-on] | long [squelch-on] | medium [squelch-on] | short [squelch-on]}

no cablelength

Syntax Description

custom

Fine-tunes the receiver sensitivity for long-haul, medium-haul, and short-haul applications.

gain-value

Custom gain value for the receiver in the range of 0x1 to 0x3F. These settings are mapped to values in the range of 0 to -45 dB.

long

Fine-tunes the receiver sensitivity for long-haul applications.

medium

Fine-tunes the receiver sensitivity for medium-haul applications.

short

Fine-tunes the receiver sensitivity for short-haul applications.

squelch-on

(Optional) Enables squelch to improve the signal-to-noise ratio.


Command Default

Default receiver sensitivity for E1 cables is applied.

Command Modes

Controller configuration

Command History

Release
Modification

12.3(17)

This command was introduced.


Usage Guidelines

This command is supported on E1 controllers only.


Note The cable line pulse gain values are not dependent upon the E1 line being configured in balanced (120-ohm) mode or unbalanced (75-ohm) mode.


Examples

The following example shows how to fine-tune the receiver sensitivity for an E1 cable on a Cisco AS5300 to support a long-haul configuration:

Router(config-controller)# cablelength long squelch-on

cablelength long

To increase the pulse of a signal at the receiver and to decrease the pulse from the transmitter using pulse equalization and line build-out for a T1 cable, use the cablelength long command in controller configuration or interface configuration mode. To return the pulse equalization and line build-out values to their default settings, use the no form of this command.

cablelength long db-gain-value db-loss-value

no cablelength long

Syntax Description

db-gain-value

Number of decibels (dB) by which the receiver signal is increased. Use one of the following values:

gain26

gain36

The default is 26 dB.

db-loss-value

Number of decibels by which the transmit signal is decreased. Use one of the following values:

0db

-7.5db

-15db

-22.5db

The default is 0 dB.


Defaults

db-gain-value: gain26
db-loss-value: 0db

Command Modes

Controller configuration for the Cisco AS5800 and Cisco MC3810.
Interface configuration for the Cisco 2600 and Cisco 3600 series routers.

Command History

Release
Modification

11.2

This command was introduced.

11.3

The following keywords were added: gain26, gain36, 0db, -7.5db, -15db, -22.5db.

12.0(5)XK

This command was modified to include support as an ATM interface configuration command for the Cisco 2600 and Cisco 3600 series routers and as a controller configuration command for the Cisco AS5800 universal access server.


Usage Guidelines

Cisco AS5800 and Cisco MC3810

Use this command for configuring the controller T1 interface on the Cisco AS5200 access server, on the Cisco AS5800 universal access server, or on the Cisco MC3810 multiservice access concentrator. The cablelength long command is used to configure DS1 links (meaning, to build CSU/DSU links) when the cable length is no longer than 655 feet.

On the Cisco MC3810, this command is supported on T1 controllers only and applies to Voice over Frame Relay, Voice over ATM, and Voice over HDLC.


Note On the Cisco MC3810, you cannot use the cablelength long command on a DSX-1 interface only. The cablelength long command can be used only on CSU interfaces.


A pulse equalizer regenerates a signal that has been attenuated and filtered by a cable loss. Pulse equalization does not produce a simple gain, but it filters the signal to compensate for complex cable loss. A gain26 receiver gain compensates for a long cable length equivalent to 26 dB of loss, whereas a gain36 compensates for 36 dB of loss.

The lengthening or building out of a line is used to control far-end crosstalk. Line build-out attenuates the stronger signal from the customer installation transmitter so that the transmitting and receiving signals have similar amplitudes. A signal difference of less than 7.5 dB is ideal. Line build-out does not produce simple flat loss (also known as resistive flat loss). Instead, it simulates a cable loss of 7.5 dB, 15 dB, or 22.5 dB so that the resulting signal is handled properly by the receiving equalizer at the other end.

Cisco 2600 and Cisco 3600 Series Routers

This command is supported on T1 long-haul links only. If you enter the cablelength long command on a DSX-1 (short-haul) interface, the command is rejected.

The transmit attenuation value is best obtained by experimentation. If the signal received by the far-end equipment is too strong, reduce the transmit level by entering additional attenuation.

Examples

Cisco AS5800 and Cisco MC3810

The following example shows how to increase the receiver gain by 36 decibels and decreases the transmitting pulse by 15 decibels for a long cable on a Cisco AS5800:

AS5800(config)# controller t1 0
AS5800(config-controller)# cablelength long gain36 -15db

The following example shows how to configure the cable length for controller T1 0 on a Cisco MC3810 to a decibel pulse gain of 36 decibels and a decibel pulse rate of -22.5 decibels:

MC3810(config)# controller t1 0
MC3810(config-controller)# cablelength long gain36 -22.5db

Cisco 2600 and Cisco 3600 Series Routers

On a Cisco 2600 or Cisco 3600 series router, the following example shows how to specify a pulse gain of 36 decibels and a decibel pulse rate of -7.5 decibels:

Router(config)# interface atm 0/2
Router(config-if)# cablelength long gain36 -7.5db

Related Commands

Command
Description

cablelength short

Sets a cable length of 655 feet or shorter for a DS1 link.


cablelength short

To set a cable length of 655 feet or shorter for a DS1 link on the Cisco MC3810 or Cisco 2600 and Cisco 3600 series routers, use the cablelength short command in controller configuration or interface configuration mode. To delete the cablelength short value, use the no form of this command.

cablelength short length

no cablelength short

Syntax Description

length

Specifies a cable length. Use one of the following values:

133—Specifies a cable length from 0 to 133 feet.

266—Specifies a cable length from 134 to 266 feet.

399—Specifies a cable length from 267 to 399 feet.

533—Specifies a cable length from 400 to 533 feet.

655—Specifies a cable length from 534 to 655 feet.


Defaults

The default is 133 feet for the Cisco AS5200 access server, Cisco AS5800 universal access server, and Cisco MC3810 multiservice access concentrator.

There is no default cable length for the Cisco 2600 and Cisco 3600 series routers.

Command Modes

Controller configuration for the Cisco AS5200 access server, Cisco AS5800 universal access server, and Cisco MC3810 multiservice access concentrator.
Interface configuration for the Cisco 2600 and Cisco 3600 series routers.

Command History

Release
Modification

11.3(2)AA

This command was introduced.

12.0(5)XK

This command was modified to include support as an ATM interface command for the Cisco 2600 and 3600 series routers and as a controller configuration command for the Cisco AS5800 universal access server.


Usage Guidelines

Cisco AS5200 Access Server, Cisco AS5800 Universal Access Server, and Cisco MC3810 Multiservice Access Concentrator

On the Cisco MC3810, the cablelength short command is used to configure DSX-1 links when the cable length is 655 feet or less than 655 feet. On the Cisco MC3810, this command is supported on T1 controllers only.


Note On the Cisco MC3810, you cannot enter the cablelength short command on a CSU interface. The cablelength short command can be used only on DSX-1 interfaces.


Cisco 2600 and Cisco 3600 Series Routers

This command is supported on T1 short-haul links only. If you enter the cablelength short command on a long-haul interface, the command is rejected.

To set cable lengths longer than 655 feet, use the cablelength long command.

This command is supported on T1 controllers only.

Cisco AS5200 Access Server, Cisco AS5800 Universal Access Server, and Cisco MC3810 Multiservice Access Concentrator

The following example shows how to set the cable length to 266 for the T1 controller in slot 1 on dial shelf 0:

Router# configure terminal
Router(config)# controller t1 1/1/0
Router(config-controller)# cablelength short 266
Router(config-controller)# end

Cisco 2600 and Cisco 3600 Series Routers

On a Cisco 2600 or Cisco 3600 series router, the following example shows how to specify a cable length from 0 to 133 feet:

Router(config)# interface atm 0/2
Router(config-if)# cablelength short 133

Related Commands

Command
Description

cablelength long

Increases the pulse of a signal at the receiver and decreases the pulse from the sender using pulse equalization and line build-out.


carrier-delay

To set the carrier delay on a serial interface, use the carrier-delay command in interface configuration mode. To return to the default carrier delay value, use the no form of this command.

carrier-delay [seconds | msec milliseconds]

no carrier-delay [seconds | msec milliseconds]

Syntax Description

seconds

(Optional) Time, in seconds, to wait for the system to change states. The range is from 0 to 60. The default is 2.

msec milliseconds

(Optional) Time, in milliseconds. The default is 50.


Defaults

seconds: 2
milliseconds: 50

Command Modes

Interface configuration

Command History

Release
Modification

10.1

This command was introduced.


Usage Guidelines

If a link goes down and comes back up before the carrier delay timer expires, the down state is effectively filtered, and the rest of the software on the switch is not aware that a link-down event occurred. Therefore, a large carrier delay timer results in fewer link-up/link-down events being detected. On the other hand, setting the carrier delay time to 0 means that every link-up/link-down event is detected.

In most environments a lower carrier delay is better than a higher one. The exact value that you choose depends on the nature of the link outages that you expect to see in your network and how long you expect those outages to last.

If data links in your network are subject to short outages, especially if those outages last less than the time it takes for your IP routing to converge, you should set a relatively long carrier delay value to prevent these short outages from causing unnecessary churn in your routing tables. If outages in your network tend to be longer, you might want to set a shorter carrier delay so that the outages are detected sooner, and the IP route convergence begins and ends sooner.

Examples

The following example shows how to change the carrier delay to 5 seconds:

Router(config)# interface serial 0
Router(config-if)# carrier-delay 5

channel-group (EtherChannel)

To assign a Fast Ethernet interface to an EtherChannel group, use the channel-group command in interface configuration mode. To remove the channel-group configuration from the interface, use the no form of this command.

Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers

channel-group port-channel-number mode on

no channel-group

Cisco Catalyst Switches

channel-group port-channel-number mode {on | auto [non-silent] | desirable [non-silent]}

no channel-group

Syntax Description

port-channel-number

Specifies the port-channel group number; see the "Usage Guidelines" section for valid values.

mode

Specifies the EtherChannel mode of the interface.

on

Forces the port to channel without Port Aggregation Protocol (PAgP).

auto

Places a port into a passive negotiating state in which the port responds to PAgP packets it receives but does not initiate PAgP packet negotiation.

non-silent

(Optional) Used with the auto or desirable mode when traffic is expected from the other device.

desirable

Places a port into an active negotiating state in which the port initiates negotiations with other ports by sending PAgP packets.


Defaults

No channel groups are assigned.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(7)XE

This command was introduced on Cisco Catalyst 6000 family switches.

12.1(3a)E3

The number of valid values for the port-channel-number argument was changed; see the "Usage Guidelines" section for valid values.

12.2(2)XT

This command was introduced on the Cisco 2600 series, Cisco 3600 series, and Cisco 3700 series routers.

12.2(8)T

This command was integrated into Cisco IOS Release 12.2(8)T on the Cisco 2600 series, the Cisco 3600 series, and the Cisco 3700 series routers.


Usage Guidelines

IP Address for the Physical Interface

You do not have to disable the IP address that is assigned to a physical interface that is part of a channel group, but Cisco highly recommends doing so.

Layer-2 and Layer-3 Port Channels

You can create both Layer 2 and Layer 3 port channels by entering the interface port-channel command or, when the channel-group gets its first physical interface assignment. The port channels are not created at run time, nor are they created dynamically.

You do not have to create a port-channel interface before assigning a physical interface to a channel group. A port-channel interface is automatically created when the channel group gets its first physical interface, if it is not already created.

Propagation of Configuration and Attribute Changes

Any configuration or attribute changes you make to the port-channel interface are propagated to all interfaces within the same channel group as the port channel. (for example, configuration changes are also propagated to the physical interfaces that are not part of the port-channel, but are part of the channel group.)

The on Keyword

When you use the on keyword, a usable EtherChannel exists only when a port group in "on" mode is connected to another port group in the "on" mode.

Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers

You do not have to create a port-channel interface before assigning a physical interface to a channel group. A port-channel interface is created automatically when the channel group gets its first physical interface, if it is not already created.

Cisco Catalyst Switches

The number of valid values for port-channel-number depends on the software release. For software releases prior to Cisco IOS  Release 12.1(3a)E3, valid values are from 1 to 256; for Cisco IOS Release 12.1(3a)E3, 12.1(3a)E4, and 12.1(4)E1, valid values are from 1 to 64. Cisco IOS Release 12.1 E and later releases support a maximum of 64 values ranging from 1 to 256.


Caution Do not enable Layer 3 addresses on the physical EtherChannel interfaces. Do not assign bridge groups on the physical EtherChannel interfaces because loops will result.

Examples

The following example shows how to add EtherChannel interface 1/0 to the EtherChannel group specified by port-channel 1:

Router(config-if)# channel-group 1 mode on

Related Commands

Command
Description

interface port-channel

Accesses or creates the IDB port channel.

show interfaces port-channel

Displays statistics for all interfaces configured.


channel-group (Fast EtherChannel)

To assign a Fast Ethernet interface to a Fast EtherChannel group, use the channel-group command in interface configuration mode. To remove a Fast Ethernet interface from a Fast EtherChannel group, use the no form of this command.

channel-group channel-number

no channel-group channel-number

Syntax Description

channel-number

Port-channel number previously assigned to the port-channel interface using the interface port-channel global configuration command. The range is from 1 to 4.


Defaults

No channel group is configured.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CA

This command was introduced.


Usage Guidelines

Before you assign a Fast Ethernet interface to a Fast EtherChannel group, you must first create a port-channel interface. To create a port-channel interface, use the interface port-channel global configuration command.

If the Fast Ethernet interface has an IP address assigned, you must disable it before adding the Fast Ethernet interface to the Fast EtherChannel. To disable an existing IP address on the Fast Ethernet interface, use the no ip address command in interface configuration mode.

The Fast EtherChannel feature allows multiple Fast Ethernet point-to-point links to be bundled into one logical link to provide bidirectional bandwidth of up to 800 Mbps. Fast EtherChannel can be configured between Cisco 7500 series routers and Cisco 7000 series routers with the 7000 Series Route Switch Processor (RSP7000) and 7000 Series Chassis Interface (RSP7000CI) or between a Cisco 7500 series router or a Cisco 7000 series router with the RSP7000 and RSP700CI and a Cisco Catalyst 5000 switch.

A maximum of four Fast Ethernet interfaces can be added to a Fast EtherChannel group.


Caution The port-channel interface is the routed interface. Do not enable Layer 3 addresses on the physical Fast Ethernet interfaces. Do not assign bridge groups on the physical Fast Ethernet interfaces because it creates loops. Also, you must disable spanning tree.

To display information about the Fast EtherChannel, use the show interfaces port-channel EXEC command.

Examples

The following example shows how to add Fast Ethernet 1/0 to the Fast EtherChannel group specified by port-channel 1:

Router(config)# interface port-channel 1
Router(config-if)# exit
Router(config)# interface fastethernet 1/0/
Router(config-if)# channel-group 1

Related Commands

Command
Description

interface port-channel

Specifies a Fast EtherChannel and enters interface configuration mode.

ip address

Sets a primary or secondary IP address on an interface.

show interfaces port-channel

Displays the information about the Fast EtherChannel on Cisco 7500 series routers and Cisco 7000 series routers with the RSP7000 and RSP7000CI.


channelized

To configure the T3 controller for channelized mode, use the channelized command in configuration controller mode. To configure the T3 controller for unchannelized mode, use the no form of this command.

channelized

no channelized

Syntax Description

This command has no arguments or keywords.

Defaults

The T3 controller is channelized.
Channelized: maximum transmission unit (MTU) size is set to 1500.
Unchannelized: MTU size is set to 4470.

Command Modes

Configuration controller

Command History

Release
Modification

12.0(14)S

This command was introduced.

12.1(5a)E

This command was integrated into Cisco IOS Release 12.1(5a)E.

12.2(13)T

This command was integrated into Cisco IOS Release 12.2(13)T.


Usage Guidelines

Use the no channelized configuration controller command to configure the T3 controller for unchannelized mode. When you configure the PA-MC-2T3+ port adapter on a Cisco 7500 series router with the no channelized command, the MTU size is set to 4470. In channelized mode, the default MTU size is 1500. The change in MTU sizes will cause a memory recarve and CBus complex to occur, disrupting all traffic on the router for several minutes.

The following message will be displayed when switching between channelized and unchannelized modes on a Cisco 7500 series router:

Change to subrate mode will cause cbus complex reset. Proceed? [yes/no]: Y

Type Y for "yes" at the end of the warning. At the prompt, type ^Z to exit. You will exit configuration mode and enter unchannelized mode.

Examples

The following example shows how to configure unchannelized mode on a PA-MC-2T3+ port adapter in slot 1 of a Versatile Interface Processor version 2 (VIP2) or VIP4 in a Cisco 7500 series router:

Router# configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
Router(config)# controller T3 1/1/0
Router(config-controller)# no channelized
Change to subrate mode will cause cbus complex reset. Proceed? [yes/no]: Y
^Z

clear aim

To clear the data compression Advanced Interface Module (AIM) daughter card registers and reset the hardware, use the clear aim command in privileged EXEC mode.

clear aim element-number

Syntax Description

element-number

Number of AIM slot. AIM slots begin with 0.


Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(1)T

This command was introduced.


Usage Guidelines

The clear aim command is used to reset the data compression AIM hardware. This command is used if the compression Advanced Interface Module (CAIM) hardware becomes "stuck" or hangs for some reason. The CAIM registers are cleared, and the hardware is reset upon execution. All compression history is lost when the CAIM is reset.

This command is supported only on Cisco 2600 series routers.

Examples

The following example shows how to use the clear aim command. This command will reset the hardware, flushing the buffers and history for all compression tasks currently under operation:

Router# clear aim 0
Router#
1w0d: %CAIM-6-SHUTDOWN: CompressionAim0 shutting down
1w0d: %CAIM-6-STARTUP: CompressionAim0 starting up

Related Commands

Command
Description

show pas caim

Displays the IDPROM contents for each AIM board in the Cisco 2600 series routers.

test aim eeprom

Tests the data compression AIM after it is installed in a Cisco 2600 series router.


clear controller

To reset the T1 or E1 controller, use the clear controller command in user EXEC or privileged EXEC mode.

Cisco 7200 Series and Cisco 7500 Series Routers

clear controller {t1 | e1} slot/port

Cisco AS5200 Series and Cisco AS5300 Series Routers

clear controller {t1 | e1} number

Syntax Description

t1

T1 controller.

e1

E1 controller.

slot/port

Backplane slot number and port number on the interface. Refer to your hardware installation manual for the specific slot and port numbers.

number

Network interface module (NIM) number, in the range from 0 to 2.


Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.1

This command was introduced.


Examples

The following example resets the T1 controller at slot 4, port 0 on a Cisco 7500 series router:

Router# clear controller t1 4/0

The following example resets the E1 controller at NIM 0:

Router# clear controller e1 0

Related Commands

Command
Description

controller

Configures a T1, E1, or J1 controller and enters controller configuration mode.


clear counters

To clear the interface counters, use the clear counters command in user EXEC or privileged EXEC mode.

clear counters [interface-type interface-number]

Cisco 7200 Series and 7500 Series with a Packet over SONET Interface Processor

clear counters [interface-type] slot/port

Cisco 7500 Series with Ports on VIP Cards

clear counters [interface-type] slot/port-adapter/port

Syntax Description

interface-type

(Optional) Specifies the interface type; one of the keywords listed in Table 2.

number

(Optional) Specifies the interface number displayed with the show interfaces command.

slot

Slot number. Refer to the appropriate hardware manual for slot and port information.

port

Port number. Refer to the appropriate hardware manual for slot and port information.

port-adapter

Port adapter number. Refer to the appropriate hardware manual for information about port adapter compatibility.


Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.

11.2 F

The virtual-access keyword was added.

11.3

The following keywords were added or modified:

vg-anylan keyword was added.

posi keyword was changed to pos.

12.2(15)T

The ethernet and serial keywords were removed because the LAN Extension feature is no longer available in Cisco IOS software.


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). Table 2 lists the command keywords and their descriptions.


Note This command does not clear counters retrieved using Simple Network Management
Protocol (SNMP), but only those seen with the show interface EXEC command. However, variables seen with the show interface command that could affect routing, such as load and reliability, or non-cumulative variables, such as input or output rates, are not cleared.


Table 2 clear counters Interface Type Keywords

Keyword
Interface Type

async

Asynchronous interface

bri

ISDN BRI

dialer

Dialer interface

ethernet

Ethernet interface

fast-ethernet

Fast Ethernet interface

fddi

FDDI

hssi

High-Speed Serial Interface (HSSI)

line

Terminal line

loopback

Loopback interface

null

Null interface

port-channel

Port channel interface

pos

Packet OC-3 interface

serial

Synchronous serial interface

switch

Switch interface

tokenring

Token Ring interface

tunnel

Tunnel interface (IEEE 02.5)

vg-anylan

100VG-AnyLAN port adapter

virtual-access

Virtual-access interface (Refer to the Cisco IOS Dial Technologies Command Reference for details on virtual templates.)

virtual-template

Virtual-template interface (Refer to the Cisco IOS Dial Technologies Command Reference for details on virtual templates.)

virtual-tokenring

Virtual token ring interface


Examples

The following example clears all interface counters:

Router# clear counters

The following example clears the Packet OC-3 interface counters on a POSIP card in slot 1 on a Cisco 7500 series router:

Router# clear counters pos 1/0

The following example clears the interface counters on a Fast EtherChannel interface.

Router# clear counter port-channel 1

Clear "show interface" counters on all interfaces [confirm] Y
%CLEAR-5-COUNTERS: Clear counter on all interfaces by console 1

Related Commands

Command
Description

show interfaces

Displays the statistical information specific to a serial interface.

show interfaces port-channel

Displays the information about the Fast EtherChannel on Cisco 7500 series routers and Cisco 7000 series routers with the RSP7000 and RSP7000CI.


clear dsip tracing

To clear Distributed System Interconnect Protocol (DSIP) tracing statistics (trace logging), use the clear dsip tracing command in privileged EXEC mode.

clear dsip tracing {counters | tracing} [control | data | ipc]

Syntax Description

counters

Clears the DSIP counters.

tracing

Clears the DSIP tracing buffers.

control

(Optional) Clears the control counters or tracing buffers.

data

(Optional) Clears the data counters or tracing buffers.

ipc

(Optional) Clears the interprocess communication (IPC) counters or tracing buffers.


Defaults

If no option is specified, all control, data, and IPC counters or tracing buffers are cleared.

Command Modes

Privileged EXEC

Command History

Release
Modification

11.3(2)AA

This command was introduced.


Usage Guidelines

Use this command to clear the counters displayed with the show dsip tracing privileged EXEC command.

Examples

The following example shows how to clear the DSIP tracing counters (including data, control, and IPC counters):

Router# clear dsip tracing

Related Commands

Command
Description

show dsip version

Displays DSIP version information.


clear hub

To reset and reinitialize the hub hardware connected to an interface of a Cisco 2505 or Cisco 2507 router, use the clear hub command in user EXEC or privileged EXEC mode.

clear hub ethernet number

Syntax Description

ethernet

Hub in front of an Ethernet interface.

number

Hub number to clear, starting with 0. Because there is only one hub, this number is 0.


Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.3

This command was introduced.


Examples

The following example clears hub 0:

Router# clear hub ethernet 0

Related Commands

Command
Description

hub

Enables and configures a port on an Ethernet hub of a Cisco 2505 or Cisco 2507 router.


clear hub counters

To set the hub counters on an interface of a Cisco 2505 or Cisco 2507 router to zero, use the clear hub counters command in user EXEC or privileged EXEC mode.

clear hub counters [ether number [port [end-port]]]

Syntax Descriptionn

ether

(Optional) Hub in front of an Ethernet interface.

number

(Optional) Hub number for which to clear counters. Because there is currently only one hub, this number is 0. If you specify the keyword ether, you must specify the number.

port

(Optional) Port number on the hub. On the Cisco 2505 router, port numbers range from 1 to 8. On the Cisco 2507 router, port numbers range from 1 to 16. If a second port number follows, this port number indicates the end of a port range. If you do not specify a port number, counters for all ports are cleared.

end-port

(Optional) Ending port number of a range.


Defaults

If no port numbers are specified, counters for all ports are cleared.

Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.3

This command was introduced.


Examples

The following example shows how to clear the counters displayed by a show hub command for all ports on hub 0:

Router# clear hub counters ether 0

Related Commands

Command
Description

show hub

Displays information about the hub (repeater) on an Ethernet interface of a Cisco 2505 or Cisco 2507 router.


clear interface fastethernet

To reset the controller for a specified Fast Ethernet interface, use the clear interface fastethernet command in privileged EXEC mode.

Cisco 4500 and Cisco 4700 Series

clear interface fastethernet interface-number

Cisco 7200 and Cisco 7500 Series

clear interface fastethernet slot/port

Cisco 7500 Series with a VIP

clear interface fastethernet slot/port-adapter/port

Syntax Description

interface-number

Port, connector, or interface card number. On a Cisco 4500 or Cisco 4700 Series router, specifies the number of the network processor module (NPM). The numbers are assigned at the factory at the time of installation or when added to a system.

slot

Slot number. Refer to the appropriate hardware manual for slot and port information.

/port

Port number. Refer to the appropriate hardware manual for slot and port information.

/port-adapter

Port adapter number. Refer to the appropriate hardware manual for information about port adapter compatibility.


Command Modes

Privileged EXEC

Command History

Release
Modification

11.2

This command was introduced.


Examples

Cisco 4500 Series

The following example resets the controller for Fast Ethernet interface 0 on a Cisco 4500:

Router# clear interface fastethernet 0

Cisco 7200 and Cisco 7500 Series

The following example resets the controller for the Fast Ethernet interface located in slot 1, port 0 on a Cisco 7200 series router or Cisco 7500 series router:

Router# clear interface fastethernet 1/0

Cisco 7500 Series with a VIP

The following example resets the controller for the Fast Ethernet interface located in slot 1, port adapter 0, port 0 on a Cisco 7500 series router with a virtual interface processor (VIP):

Router# clear interface fastethernet 1/0/0

Related Commands

Command
Description

clear counters

Clears the interface counters.

show interfaces

Displays statistics for all interfaces configured on the router or access server.

show interfaces serial

Displays information about a serial interface.


clear interface serial

To reset the statistical information specific to a serial interface, use the clear interface serial command in user EXEC or privileged EXEC mode.

clear interface serial dial-shelf/slot/t3-port:t1-num:chan-group

Syntax Description

dial-shelf

Dial shelf chassis in the Cisco AS5800 access server that contains the CT3 interface card.

/slot

Location of the CT3 interface card in the dial shelf chassis.

/t3-port

T3 port number. The only valid value is 0.

:t1-num

T1 time slot in the T3 line. The value can be from 1 to 28.

:chan-group

Channel group identifier.


Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

The clear interface serial command clears the interface hardware. To reset the counters for an interface, use the clear counters command with the serial keyword specified. To confirm at the prompt, use the show interfaces serial command.

Examples

The following example clears the interface hardware, disconnecting any active lines:

Router# clear interface serial 1/4/0:2:23

Related Commands

Command
Description

clear counters

Clears the interface counters.

show interfaces

Displays statistics for all interfaces configured on the router or access server.

show interfaces fastethernet

Displays information about a fastethernet interface.


clear interface

To reset the hardware logic on an interface, use the clear interface command in user EXEC or privileged EXEC mode.

clear interface type number [name-tag]

Cisco 7200 Series and Cisco 7500 Series with a Packet OC-3 Interface Processor

clear interface type slot/port

Cisco 7500 Series with Ports on VIP Cards

clear interface type slot/port-adapter/port

Cisco 7500 Series

clear interface type slot/port[:channel-group]

Cisco 7500 Series with a CT3IP Port Adapter

clear interface type slot/port-adapter/port[:t1-channel]

Syntax Description

type

Interface type; it is one of the keywords listed in Table 3.

number

Port, connector, or interface card number.

name-tag

(Optional for use with the Redundant Link Manager (RLM) feature) Logic name to identify the server configuration so that multiple server configurations can be entered.

slot

Number of the slot being configured. Refer to the appropriate hardware manual for slot and port information.

port

Number of the port being configured. Refer to the appropriate hardware manual for slot and port information.

port-adapter

Number of the port adapter being configured. Refer to the appropriate hardware manual for information about port adapter compatibility.

:channel-group

(Optional) On Cisco 7500 series routers that support channelized T1, specifies the channel number from 0 to 23. This number is preceded by a colon.

:t1-channel

(Optional) For the CT3IP port adapter, the T1 channel is a number between 1 and 28. T1 channels on the CT3IP are numbered 1 to 28 rather than the more traditional zero-based scheme (0 to 27) used with other Cisco products. This numbering scheme ensures consistency with telco numbering schemes for T1 channels within channelized T3 equipment.


Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.

11.3

The following keywords were added or modified:

vg-anylan keyword added

posi keyword changed to pos

12.0(3)T

The following optional argument was added for the RLM feature:

name-tag


Usage Guidelines

Under normal circumstances, you do not need to clear the hardware logic on interfaces.

This command clears all the current interface hardware logic unless the type and number arguments are specified to clear only a specific interface type (serial, Ethernet, Token Ring, and so on). Table 3 lists the command keywords and their descriptions.

Table 3 clear interface Type Keywords

Keyword
Interface Type

async

Async interface

atm

ATM interface

bri

ISDN BRI

ethernet

Ethernet interface

fddi

FDDI

hssi

High-Speed Serial Interface (HSSI)

loopback

Loopback interface

null

Null interface

port-channel

Port channel interface

pos

Packet OC-3 Interface Processor

serial

Synchronous serial interface

switch

Switch interface

tokenring

Token Ring interface

tunnel

Tunnel interface

vg-anylan

100VG-AnyLAN port adapter


Examples

The following example shows how to reset the interface logic on HSSI interface 1:

Router# clear interface hssi 1

The following example shows how to reset the interface logic on Packet OC-3 interface 0 on the POSIP in slot 1:

Router# clear interface pos 1/0

The following example shows how to reset the interface logic on T1 0 on the CT3IP port adapter in slot 9:

Router# clear interface serial 9/0/0:0

The following example shows how to reset the interface logic on Fast EtherChannel interface 1:

Router# clear interface port-channel 1

The following example shows how to reset demonstrates the use of the clear interface command with the RLM feature:

Router# clear interface loopback 1

Router#
02:48:52: rlm 1: [State_Up, rx ACTIVE_LINK_BROKEN] over link [10.1.1.1(Loopback1), 
10.1.4.1]
02:48:52: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] requests activation
02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is deactivated
02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] = socket[10.1.1.1, 10.1.4.1]
02:48:52: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.1(Loopback1), 
10.1.4.1] for user RLM_MGR
02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is opened
02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.5.1] = socket[10.1.1.1, 10.1.5.1]
02:48:52: rlm 1: [State_Recover, rx USER_SOCKET_OPENED] over link [10.1.1.1(Loopback1), 
10.1.5.1] for user RLM_MGR
02:48:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.5.1] is opened
02:48:52: rlm 1: [State_Recover, rx START_ACK] over link [10.1.1.2(Loopback2), 10.1.4.2]
02:48:52: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] is activated
02:48:52: rlm 1: [State_Up, rx LINK_OPENED] over link [10.1.1.1(Loopback1), 10.1.4.1]

Router# show rlm group 1 status   

RLM Group 1 Status
 User/Port: RLM_MGR/3000 
 Link State: Up         Last Link Status Reported: Up_Recovered
 Next tx TID: 4         Last rx TID: 0
 Server Link Group[r1-server]:
  link [10.1.1.1(Loopback1), 10.1.4.1] = socket[standby, 10.1.1.1, 10.1.4.1]
  link [10.1.1.2(Loopback2), 10.1.4.2] = socket[active, 10.1.1.2, 10.1.4.2]
 Server Link Group[r2-server]:
  link [10.1.1.1(Loopback1), 10.1.5.1] = socket[opening, 10.1.1.1, 10.1.5.1]
  link [10.1.1.2(Loopback2), 10.1.5.2] = socket[opening, 10.1.1.2, 10.1.5.2]
Router#
Router#
02:49:52: rlm 1: [State_Up, rx UP_RECOVERED_MIN_TIMEOUT]
02:49:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] requests activation
02:49:52: rlm 1: [State_Switch, rx SWITCH_ACK] over link [10.1.1.1(Loopback1), 10.1.4.1]
02:49:52: rlm 1: link [10.1.1.2(Loopback2), 10.1.4.2] is deactivated
02:49:52: rlm 1: link [10.1.1.1(Loopback1), 10.1.4.1] is activated

Related Commands

Command
Description

interface

Defines the IP addresses of the server, configures an interface type, and enters interface configuration mode.

show rlm group

Displays the status of the RLM group.

shutdown (RLM)

Shuts down all of the links under the RLM group.


clear ipc statistics

To clear all interprocess communication (IPC) statistics, use the clear ipc statistics command in privileged EXEC mode.

clear ipc statistics

Syntax Description

This command has no arguments or keywords.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.2(15)T

This command was introduced.


Usage Guidelines

The clear ipc statistics command clears all the IPC statistics and is useful for troubleshooting issues with IPC services.

Examples

The following example shows how to clear all of the statistics used by IPC services. A show ipc status command is issued first to display the current IPC counters for a local IPC server. The clear ipc statistics command is then entered to clear and reset the counters. A final show ipc status command is issued to show that all the counters, except those counters that show the packets sent since the clearing, are reset to zero.

Router# show ipc status

IPC System Status

Time last IPC stat cleared : never 

This processor is the IPC master server.
Do not drop output of IPC frames for test purposes.

1000 IPC Message Headers Cached.

                                                      Rx Side     Tx Side

Total Frames                                              189         140
Total from Local Ports                                    189          70
Total Protocol Control Frames                              70          44
Total Frames Dropped                                        0           0

                            Service Usage

Total via Unreliable Connection-Less Service              145           0
Total via Unreliable Sequenced Connection-Less Svc          0           0
Total via Reliable Connection-Oriented Service             44          70

                     IPC Protocol Version 0

Total Acknowledgements                                     70          44
Total Negative Acknowledgements                             0           0

                            Device Drivers

Total via Local Driver                                      0           0
Total via Platform Driver                                   0          70
Total Frames Dropped by Platform Drivers                    0           0

                    Reliable Tx Statistics

Re-Transmission                                                         0
Re-Tx Timeout                                                           0

         Rx Errors                              Tx Errors

Unsupp IPC Proto Version          0  Tx Session Error                  0
Corrupt Frame                     0  Tx Seat Error                     0
Duplicate Frame                   0  Destination Unreachable           0
Out-of-Sequence Frame             0  Tx Test Drop                      0
Dest Port does Not Exist          0  Tx Driver Failed                  0
Rx IPC Msg Alloc Failed           0  Ctrl Frm Alloc Failed             0
Unable to Deliver Msg             0

         Buffer Errors                          Misc Errors

IPC Msg Alloc                     0  IPC Open Port                     0
Emer IPC Msg Alloc                0  No HWQ                            0
IPC Frame PakType Alloc           0  Hardware Error                    0
IPC Frame MemD Alloc              0

         Tx Driver Errors

No Transport                      0
MTU Failure                       0
Dest does not Exist               0

Router# clear ipc statistics

Router# show ipc status

IPC System Status

Time last IPC stat cleared : 00:00:03 

This processor is the IPC master server.
Do not drop output of IPC frames for test purposes.

1000 IPC Message Headers Cached.

                                                      Rx Side     Tx Side

Total Frames                                               26           0
Total from Local Ports                                     26           0
Total Protocol Control Frames                               0           0
Total Frames Dropped                                        0           0

Service Usage

Total via Unreliable Connection-Less Service               26           0
Total via Unreliable Sequenced Connection-Less Svc          0           0
Total via Reliable Connection-Oriented Service              0           0

IPC Protocol Version 0

Total Acknowledgements                                      0           0
Total Negative Acknowledgements                             0           0

                            Device Drivers

Total via Local Driver                                      0           0
Total via Platform Driver                                   0           0
Total Frames Dropped by Platform Drivers                    0           0

                    Reliable Tx Statistics

Re-Transmission                                                         0
Re-Tx Timeout                                                           0

         Rx Errors                              Tx Errors

Unsupp IPC Proto Version          0  Tx Session Error                  0
Corrupt Frame                     0  Tx Seat Error                     0
Duplicate Frame                   0  Destination Unreachable           0
Out-of-Sequence Frame             0  Tx Test Drop                      0
Dest Port does Not Exist          0  Tx Driver Failed                  0
Rx IPC Msg Alloc Failed           0  Ctrl Frm Alloc Failed             0
Unable to Deliver Msg             0

         Buffer Errors                          Misc Errors

IPC Msg Alloc                     0  IPC Open Port                     0
Emer IPC Msg Alloc                0  No HWQ                            0
IPC Frame PakType Alloc           0  Hardware Error                    0
IPC Frame MemD Alloc              0

         Tx Driver Errors

No Transport                      0
MTU Failure                       0
Dest does not Exist               0

Related Commands

Command
Description

show ipc

Displays IPC statistics.


clear service-module serial

To reset an integrated CSU/DSU, use the clear service-module serial command in privileged EXEC mode.

clear service-module serial number

Syntax Description

number

Number of the serial interface.


Command Modes

Privileged EXEC

Command History

Release
Modification

11.2

This command was introduced.


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 software performs an automatic software reset in case of two consecutive configuration failures.

The CSU/DSU module is not reset with the clear interface command.


Caution If you experience technical difficulties with your router and intend to contact customer support, refrain from using this command. This command erases the router's past CSU/DSU performance statistics. To clear only the CSU/DSU performance statistics, issue the clear counters command.

Examples

The following example show how to reset the CSU/DSU on a router:

Router# clear service-module serial 0

Related Commands

Command
Description

clear counters

Clears the interface counters.

test service-module

Performs self-tests on an integrated CSU/DSU serial interface module, such as a 4-wire, 56/64-kbps CSU/DSU.


clock rate

To configure the clock rate for the hardware connections on serial interfaces such as network interface modules (NIMs) and interface processors to an acceptable bit rate, use the clock rate command in interface configuration mode. To remove the clock rate if you change the interface from a DCE to a DTE device, use the no form of this command. Using the no form of this command on a DCE interface sets the clock rate to the hardware-dependent default value.

clock rate bps

no clock rate

Syntax Description

bps

Desired clock rate, in bits per second: 1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000, 72000, 125000, 148000, 250000, 500000, 800000, 1000000, 1300000, 2000000, 4000000, or 8000000.

For the synchronous serial port adapters (PA-8T-V35, PA-8T-X21, PA-8T-232, and PA-4T+), a nonstandard clock rate can be used. You can enter any value from 300 to 8000000 bps. The clock rate you enter is rounded (adjusted), if necessary, to the nearest value that your hardware can support except for the following standard rates: 1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 56000, 64000, 128000, or 2015232.


Defaults

No clock rate is configured.

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.

11.3

This command was modified to include nonstandard clock rates for the PA-8T-V35, PA-8T-X21, PA-8T-232, and PA-4T+ synchronous serial port adapters.


Usage Guidelines

Cable Length

Be aware that the fastest speeds might not work if your cable is too long, and that speeds faster than 148,000 bits per second are too fast for EIA/TIA-232 signaling. It is recommended that you only use the synchronous serial EIA/TIA-232 signal at speeds up to 64,000 bits per second. To permit a faster speed, use EIA/TIA-449 or V.35.

Synchronous Serial Port Adapters

For the synchronous serial port adapters (PA-8T-V35, PA-8T-X21, PA-8T-232, and PA-4T+) on Cisco 7200 series routers, and on second-generation Versatile Interface Processors (VIP2s) in Cisco 7500 series routers, the clock rate you enter is rounded (if needed) to the nearest value that your hardware can support. To display the clock rate value for the port adapter, use the show running-config command.

If you plan to netboot your router over a synchronous serial port adapter interface and have a boot image prior to Cisco IOS Release 11.1(9)CA that does not support nonstandard (rounded) clock rates for the port adapters, you must use one of the following standard clock rates:

1200

2400

4800

9600

19200

38400

56000

64000

Examples

The following example shows how to set the clock rate on the first serial interface to 64,000 bps:

Router(config)# interface serial 0
Router(config-if)# clock rate 64000

The following example shows how to set the clock rate on a synchronous serial port adapter in slot 5, port 0 to 1,234,567 bps. In this example, the clock rate is adjusted to 1,151,526 bps.

Router(config)# interface serial 5/0
Router(config-if)# clock rate 1234567
%clock rate rounded to nearest value that your hardware can support.

The following example shows how to determine the exact clock rate that the serial interface was rounded to by using the show running-config command.

Router# show running-config

Building configuration...
.
.
.
!
interface Serial5/0
 no ip address
 clock rate 1151526
!
.
.
.

clock rate line

To configure the line clock rate for serial ports 0 or 1 in DTE mode, use the clock rate line command in interface configuration mode. To cancel the clock rate line value, use the no form of this command.

clock rate line rate

no clock rate line rate

Syntax Description

rate

Network clock line rate, in kbps per second. The range is from 56 to 2048. The value entered should be a multiple of 8 of the value set for the network-clock base-rate command. There is no default rate.


Defaults

No clock rate is set.

Command Modes

Interface configuration

Command History

Release
Modification

11.3(1)MA

This command was introduced on the Cisco MC3810 multiservice access concentrator.


Usage Guidelines

This command specifies the rate of the incoming clock so that the appropriate internal clock scaling can be performed.

To configure the clock rate for a serial port in DTE mode, use the clock rate network-clock command.

Examples

The following example show how to configure the clock rate on serial 1 in DTE mode:

Router(config)# interface serial 1
Router(config-if)# clock rate line 2048

Related Commands

Command
Description

clock rate network-clock

Configures the network clock speed for serial ports 0 or 1 in DCE mode.

clock source

Specifies the clock source of a DS1 link on the Cisco MC3810 multiservice access concentrator.

network-clock base-rate

Configures the network clock base rate for universal I/O serial ports 0 and 1 on the Cisco MC3810 multiservice access concentrator.


clock rate network-clock

To configure the network clock rate (speed) for serial ports 0 or 1 in DCE mode, use the clock rate network-clock command in interface configuration mode. To cancel the network clock rate value, use the no form of this command.

clock rate network-clock rate

no clock rate network-clock rate

Syntax Description

rate

Network clock rate, in kbps per second. The range is from 56 to 2048. The value entered should be a multiple of the value set for the network-clock base-rate command. There is no default rate.


Defaults

No clock rate is set.

Command Modes

Interface configuration

Command History

Release
Modification

11.3(1)MA

This command was introduced on the Cisco MC3810 multiservice access concentrator.


Usage Guidelines

This command uses a synchronized clock on the serial port. The use of this command allows the clock on the serial port to be synchronized with the clock source of controller T1 0.

To configure the clock rate for a serial port in DTE mode, use the clock rate line command.

Examples

The following example shows how to configure the clock rate on serial port 1 in DCE mode:

Router(config)# interface serial 1
Router(config-if)# clock rate network-clock 2048

Related Commands

Command
Description

clock rate line

Configures the line clock rate for serial ports 0 or 1 in DTE mode.

clock source (MC3810)

Specifies the clock source of a DS1 link on the Cisco MC3810 multiservice access concentrator.

network-clock base-rate

Configures the network clock base rate for universal I/O serial ports 0 and 1 on the Cisco  MC3810 multiservice concentrator.


clock source (controller)

To set the T1-line clock source for the Multichannel Interface Processor (MIP) in the Cisco 7200 series and Cisco 7500 series, a T3 interface, or a PA-T3 serial port adapter, use the clock source command in controller configuration mode. To restore the clock source to its default setting, use the no form of this command.

clock source {line {primary | secondary} | internal}

no clock source

Syntax Description

line

Specifies that the interface will clock its transmitted data from a clock recovered from the line's receive data stream. This is the default.

primary

Specifies the source of primary line clocking. The default primary time-division multiplexing (TDM) clock source is from the T0 controller.

secondary

Specifies the source of secondary line clocking. The default secondary TDM clock source is from the T1 controller.

internal

Specifies that the interface will clock its transmitted data from its internal clock.


Defaults

The default primary TDM clock source is from the T0 controller.
The default secondary TDM clock source is from the T1 controller.
The default clock for the interface's transmitted data is from a clock recovered from the line's receive data stream from the PA-T3 serial port adapter.

Command Modes

Controller configuration

Command History

Release
Modification

10.3

This command was introduced.

11.1 CA

This command was modified to include the T3 serial port adapter and PA-T3 serial port adapter.


Usage Guidelines

This command applies to a Cisco 4000, Cisco 7000 series, Cisco 7200 series, or Cisco 7500 series router. A T3 interface on a PA-T3 serial port adapter can clock its transmitted data either from its internal clock or from a clock recovered from the line's receive data stream.

To use the clocking coming in from a T1 line, configure the clock source line primary command on the controller that has the most reliable clocking. Configure the clock source line secondary command on the controller that has the next best known clocking. With this configuration, the primary line clocking is backed up to the secondary line if the primary clocking shuts down.

Examples

The following example shows how to configure the Cisco AS5300 to use the T0 controller as the primary clocking source and the T1 controller as the secondary clocking source:

AS5200(config)# controller t1 0
AS5200(config-controller)# clock source line primary
AS5200(config-controller)# exit
AS5200(config)# controller t1 1
AS5200(config-controller)# clock source line secondary

Related Commands

Command
Description

framing

Selects the frame type for the T1 or E1 data line.

linecode

Selects the line code type for T1 or E1 line.


clock source (CT3IP)

To specify where the clock source is obtained for use by the Channelized T3 Interface Processor (CT3IP) in Cisco 7500 series routers, use the clock source command in controller configuration mode. To restore the default clock source, use the no form of this command.

clock source {internal | line | loop-timed}

no clock source

Syntax Description

internal

Specifies that the internal clock source is used. This is the default.

line

Specifies that the network clock source is used.

loop-timed

Decouples the controller clock from the system-wide clock set with the network-clock-select command. The loop-timed clock enables the Digital Voice Module (DVM) to connect to a PBX and to connect the Multiflex Trunk Module (MFT) to a central office when both the PBX and the central office function as DCE clock sources. This situation assumes that the PBX also takes the clocking from the central office, thereby synchronizing the clocks on the DVM and the MFT.


Defaults

The internal clock source is used.

Command Modes

Controller configuration

Command History

Release
Modification

11.3

This command was introduced.


Usage Guidelines

If you do not specify the clock source command, the default internal clock source is used by the CT3IP.

You can also set the clock source for each T1 channel by using the t1 clock source controller configuration command.


Note This command replaces the pos internal-clock command.


Examples

The following example sets the clock source for the CT3IP to line:

Router(config)# controller t3 9/0/0
Router(config-controller)# clock source line

Related Commands

Command
Description

network-clock-select

Specifies selection priority for the clock sources.

t1 clock source

Specifies where the clock source is obtained for use by each T1 channel on the CT3IP in Cisco 7500 series routers.


clock source (interface)

To control the clock from which a G.703-E1 interface, an E1-G.703/G.704 serial port adapter, or a PA-E3 serial port adapter clocks its transmitted data, use the clock source command in interface configuration mode. To restore the default clock source, use the no form of this command.

Cisco 7000, Cisco 7200, and Cisco 7500 Series

clock source {line | internal}

no clock source

Cisco AS5300 Access Servers

clock source {line {primary | secondary} | internal}

no clock source line {primary | secondary}

Syntax Description

line

Specifies that the interface will clock its transmitted data from a clock recovered from the line's receive data stream. This is the default.

internal

Specifies that the interface will clock its transmitted data from its internal clock.

primary

Specifies the primary time-division multiplexing (TDM) clock source.

secondary

Specifies the secondary TDM clock source.


Defaults

Cisco 7000, Cisco 7200, and Cisco 7500 Series

The clock source is obtained from the receive data stream of the line.

Cisco AS5300 Access Servers

The primary TDM clock source is from the T0 controller.
The secondary TDM clock source is from the T1 controller.

Command Modes

Interface configuration

Command History

Release
Modification

10.3

This command was introduced for the Cisco 4000 series, Cisco 7000 series with RSP7000, and Cisco 7500 series routers with the G.703 E1 interface.

11.1 CA

This command was implemented on the TDM bus in a Cisco AS5200 or Cisco AS5300 access server and was modified to support the E1-G.703/G.704 serial port adapter, PA-E3 serial port adapters, and Cisco 7200 series routers.


Usage Guidelines

Cisco 7000, Cisco 7200, and Cisco 7500 Series

A G.703-E1 interface, E1-G.703/G.704 serial port adapter, or a PA-E3 serial port adapter can clock its transmitted data from either its internal clock or from a clock recovered from the line's receive data stream.

Cisco AS5300 Access Servers

To use the clocking coming in from a T1 line, configure the clock source line primary command on the controller that has the most reliable clocking. Configure the clock source line secondary command on the controller that has the next best known clocking. With this configuration, the primary line clocking is backed up to the secondary line if the primary clocking shuts down.

Examples

Cisco 7000, Cisco 7200, and Cisco 7500 Series

The following example shows how to configure the G.703-E1 interface to clock its transmitted data from its internal clock:

Router(config)# interface serial 0/1
Router(config-if)# clock source internal

Cisco AS5300 Access Servers

The following example shows how to configure the Cisco AS5300 to use serial interface 1/0 as the primary clocking source and the serial interface 2/0 as the secondary clocking source:

AS5300(config)# interface serial 1/0
AS5300(config-if)# clock source line primary
AS5300(config-if)# exit
AS5300(config)# interface serial 2/0
AS5300(config-if)# clock source line secondary

The following example shows how to specify the T3 interface to clock its transmitted data from its internal clock:

Router(config)# interface serial 1/0
Router(config-if)# clock source internal

clock source (J1 controller)

To configure the clock source for a J1 controller, use the clock source command in controller configuration mode. To restore the clock source to its default setting, use the no form of this command.

clock source {line | internal}

no clock source

Syntax Description

line

The controller recovers the external clock from the line and provides the recovered clock to the internal (system) clock generator. The line value is the default clock source.

internal

The controller synchronizes itself to the internal (system) clock.


Defaults

Clock source is line for the J1 controller.

Command Modes

Controller configuration

Command History

Release
Modification

11.1 T

This command was introduced.

12.2(8)T

The command was introduced as a J1 controller configuration command for the Cisco 2600 and Cisco 3600 series.


Usage Guidelines

If multiple network modules are present in the router, then each J1 controller must be given a separate priority by configuration of the network-clock-select command. The controller having the highest priority will drive the internal clock.

Examples

The following example configures the clock source for line:

Router(config)# controller j1 3/0
Router(config-controller)# clock source line

Related Commands

Command
Description

network-clock-select

Sets the selection priority for a clock source.


clock source (SONET controller)

To specify the clock source of a SONET controller, use the clock source command in controller configuration mode. To restore the clock source to its default setting, use the no form of this command.

clock source {internal | line | loop}

no clock source

Syntax Description

internal

Specifies that the clock source uses the internal clock provided by the Route Switch Controller (RSC). This is the default.

line

Specifies that the clock source uses the primary system clock from the optical line and the recovered clock will go through the RSC phased locked loop (PLL) circuitry. Can be used when one or more STM-1 cards are installed.

loop

Specifies that the clock source uses the primary system clock from the optical line and the same recovered clock is used in the transmit (tx) direction without going through the RSC PLL circuitry. Can be used when only one STM-1 card is installed.


Defaults

Internal

Command Modes

Controller configuration

Command History

Release
Modification

10.3

This command was introduced.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Examples

The following example shows how to specify line timing as the clock source on a SONET controller of an STM-1 card in physical slot number 2 on a Cisco AS5850:

Router(config)# controller sonet 2/0
Router(config-controller)# clock source line

clock source (T1/E1 controller)

To set clocking for individual T1 or E1 links, use the clock source command in controller configuration mode. To return to the default, use the no form of this command.

clock source {line [primary] | internal | free-running}

no clock source

Syntax Description

line

Specifies that the phase-locked loop (PLL) on this port derives its clocking from the external source to which the port is connected, which is generally the telephone company central office (CO). This is the default.

primary

(Optional) Specifies that the PLL on this port derives its clocking from the external source to which the port is connected. This option also puts a second port, which is generally connected to the PBX, into looped-time mode. Both ports are configured with line, but only the port connected to the external source is configured with primary.

internal

Specifies that the clock is generated from the T1 or E1 controller's internal PLL.

free-running

Specifies a free-running clock derived from the oscillator on the motherboard, which is used only for testing and back-to-back connections.


Defaults

line

Command Modes

Controller configuration

Command History

Release
Modification

12.2(2)XB

This command was introduced on Cisco 2600 series and Cisco 3660 routers.

12.2(8)T

This command was integrated into Cisco IOS Release 12.2(8)T.

12.2(15)T

This command was implemented on the Cisco 2691 and the Cisco 3700 series.


Usage Guidelines

For a detailed discussion of clock sources on individual ports, see the "Clock Sources on Digital T1/E1 Voice Ports" section in the "Voice Port Configuration" chapter in the Cisco IOS Voice Configuration Library.

Examples

The following example shows the router providing clock source to two controllers:

controller E1 1/0
 framing crc4
 linecoding hdb3
 clock source internal
ds0-group timeslots 1-15 type e&m-wink-start
!
controller E1 1/1
 framing esf
 linecoding b8zs
 clock source internal
 ds0-group timeslots 1-15 type e&m-wink-start

The following example shows the digital voice hardware receiving clocking for the PLL from E1 1/0 and using this clock as a reference to clock E1 1/1. If controller E1 1/0 fails, the PLL internally generates the clock reference to drive E1 1/1.

controller E1 1/0
 framing crc4
 linecoding hdb3
 clock source line 
 ds0-group timeslots 1-15 type e&m-wink-start
!
controller E1 1/1
 framing crc4
 linecoding hdb3
 clock source internal
 ds0-group timeslots 1-15 type e&m-wink-start

Related Commands

Command
Description

controller

Configures a T1 or E1 controller and enters controller configuration mode.


clock source (T1/E1 interface)

To configure the clock source of a DS1 link, use the clock source command in interface configuration or ATM interface configuration mode. To restore the default line setting, use the no form of this command.

clock source {line | internal | loop-timed}

no clock source

Syntax Description

line

Specifies that the T1/E1 link uses the recovered clock from the line. This is the default.

internal

Specifies that the T1/E1 link uses the internal clock from the interface.

loop-timed

Specifies that the T1/E1 interface takes the clock from the Rx (line) and uses it for Tx.


Defaults

line

Command Modes

Interface configuration
ATM interface configuration for the Cisco 2600 and Cisco 3600 series routers.

Command History

Release
Modification

10.3

This command was introduced.

11.1 CA

This command was modified to support the E1-G.703/G.704 serial port adapter, PA-E3 serial port adapters, and Cisco 7200 series routers.

11.3 MA

This command was introduced as a controller configuration command for the Cisco MC3810.

12.0(5)XK

The command was introduced as an ATM interface configuration command for the Cisco 2600 and Cisco 3600 series routers.


Usage Guidelines

This command sets clocking for individual T1/E1 links.

Make sure that you specify the clock source correctly for each link, even if you are planning to specify that a certain link will provide clocking for all the links in an IMA group. Because links may be taken in and out of service, requiring that the system select another link for common clocking, any link in an IMA group may provide the common clock.

If the ATM interface is part of an IMA group, you can use the loop-timed keyword to specify that the clock source is the same as the IMA group clock source.

Examples

On a Cisco 2600 or Cisco 3600 series router, the following example specifies an internal clock source for the link:

Router(config)# interface atm 0/2
Router(config-if)# clock source internal

Related Commands

Command
Description

ima clock-mode

Sets the transmit clock mode for an ATM IMA group.


clock source (T3/E3 controller)

To specify where the clock source is obtained for use by a T3 or E3 controller, use the clock source command in controller configuration mode. To restore the default clock source, use the no form of this command.

clock source {internal | line}

no clock source

Syntax Description

internal

Specifies that the internal clock source is used. This is the default for T3.

line

Specifies that the network clock source is used. This is the default for E3.


Defaults

The internal clock source is used for T3 controllers.
The line clock source is used for E3 controllers.

Command Modes

Controller configuration

Command History

Release
Modification

12.2(11)YT

This command was introduced on the following platforms: Cisco 2650XM, Cisco 2651XM, Cisco 2691, Cisco 3660 series, Cisco 3725, and Cisco 3745 routers.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Usage Guidelines

If you do not specify the clock source command, the default clock source is used.

Configure the clock source line command if your telephone company or the remote data service unit provides the master clock of the T3 or E3 connection.

Configure the clock source internal command if your router provides the master clock of the T3 or E3 connection.


Note For a back-to-back connection between two T3 or E3 network modules, one controller must be configured for internal clocking while the other controller must be configured for line clocking.


Examples

The following example shows how to set the clock source to line:

Router(config)# controller t3 1/0
Router(config-controller)# clock source line

Related Commands

Command
Description

controller

Configures a T1 or E1 controller and enters controller configuration mode.


cmt connect

To start the processes that perform the connection management (CMT) function and to allow the ring on one fiber to be started, use the cmt connect command in user EXEC or privileged EXEC mode.

cmt connect [fddi [port | slot/port] [phy-a | phy-b]]

Syntax Description

fddi

(Optional) Identifies this as a FDDI interface.

port

(Optional) Port number. Refer to the appropriate hardware manual for slot and port information.

slot

(Optional) Slot number. Refer to the appropriate hardware manual for slot and port information.

phy-a

(Optional) Selects Physical Sublayer A.

phy-b

(Optional) Selects Physical Sublayer B.


Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.


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.

This command does not have a no form. To stop the CMT processes, use the cmt disconnect command.

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:

Router# cmt connect fddi

The following command starts both fibers on FDDI interface unit 0:

Router# cmt connect fddi 0

The following command on the Cisco 7200 series or Cisco 7500 series starts both fibers on FDDI interface unit 0:

Router# cmt connect fddi 1/0

The following command starts only Physical Sublayer A on FDDI interface unit 0:

Router# cmt connect fddi 0 phy-a

Related Commands

Command
Description

cmt disconnect

Stops the CMT processes.


cmt disconnect

To stop the processes that perform the connection management (CMT) function and to allow the ring on one fiber to be stopped, use the cmt disconnect command in user EXEC or privileged EXEC mode.

cmt disconnect [fddi [port | slot/port] [phy-a | phy-b]]

Syntax Description

fddi

(Optional) Identifies this as a FDDI interface.

port

(Optional) Port number. Refer to the appropriate hardware manual for slot and port information.

slot

(Optional) Slot number. Refer to the appropriate hardware manual for slot and port information.

phy-a

(Optional) Selects Physical Sublayer A.

phy-b

(Optional) Selects Physical Sublayer B.


Command Modes

User EXEC
Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

In normal operation, the FDDI interface is operational once the interface is connected and configured, and is turned on using the no shutdown command in interface configuration mode. 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.

This command does not have a no form. To start the CMT processes, use the cmt connect command.

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:

Router# cmt disconnect fddi

The following command stops both fibers on FDDI interface unit 0:

Router# cmt disconnect fddi 0

The following command on the Cisco 7200 series or Cisco 7500 series stops both fibers on FDDI interface unit 0:

Router# cmt disconnect fddi 1/0

The following command stops only Physical Sublayer A on the FDDI interface unit 0. This command causes the FDDI media to go into a wrapped state so that the ring will be broken.

Router# cmt disconnect fddi 0 phy-a

The following command on the Cisco 7500 series stops only Physical Sublayer A on FDDI interface unit 0 in slot 1. This command causes the FDDI media to go into a wrapped state so that the ring will be broken.

Router# cmt disconnect fddi 1/0 phy-a

Related Commands

Command
Description

cmt connect

Starts the CMT processes.


compress

To configure software compression for Link Access Procedure, Balanced (LAPB), PPP, and High-Level Data Link Control (HDLC) encapsulations, use the compress command in interface configuration mode. To disable compression, use the no form of this command.

compress {predictor | stac}

no compress {predictor | stac}

Cisco VIP2 Cards

compress {predictor | stac [distributed | software]}

[no] compress {predictor | stac [distributed | software]}

Cisco 7200 Series and Cisco 7500 Series

compress {predictor | stac [csa slot | software]}

[no] compress {predictor | stac [csa slot | software]}

PPP Encapsulation

compress [predictor | stac | mppc [ignore-pfc]]

[no] compress [predictor | stac | mppc [ignore-pfc]]

Syntax Description

predictor

Specifies that a predictor (RAND) compression algorithm will be used on LAPB and PPP encapsulation. Compression is implemented in the software installed in the router's main processor.

stac

Specifies that a Stacker (LZS) compression algorithm will be used on LAPB, HDLC, and PPP encapsulation. For all platforms except Cisco  7200 series and platforms that support the Virtual Interface Processor 2 (VIP2), compression is implemented in the software installed in the router's main processor.

On Cisco 7200 series and on VIP2s in Cisco 7500 series, specifying the compress stac command with no options causes the router to use the fastest available compression method for PPP encapsulation only:

If the router contains a compression service adapter (CSA), compression is performed in the CSA hardware (hardware compression).

If a CSA is not available, compression is performed in the software installed on the VIP2 (distributed compression).

If a VIP2 is not available, compression is performed in the router's main processor (software compression).

distributed

(Optional) Specifies that compression is implemented in the software that is installed in a VIP2. If the VIP2 is not available, compression is performed in the router's main processor (software compression).

software

(Optional) Specifies that compression is implemented in the Cisco IOS software installed in the router's main processor.

csa slot

(Optional) Specifies the CSA to use for a particular interface.

mppc

(Optional) Specifies that the Microsoft Point-to-Point Compression (MPPC) compression algorithm be used.

ignore-pfc

(Optional) Specifies that the protocol field compression flag negotiated through Link Control Protocol (LCP) will be ignored.


Defaults

Compression is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

10.3

This command was introduced.

11.3 P

The following keywords were added:

distributed

software

csa slot

11.3 T

The following keywords were added:

mppc

ignore-pfc



Note This command replaces the compress predictor command.


Usage Guidelines

Point-to-Point Compression

Compression reduces the size of frames through lossless data compression. You can configure point-to-point software compression for all LAPB, PPP, and HDLC encapsulations. 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.

End-point devices must be configured to use the same compression method (predictor, Stacker or MPPC).

HDLC encapsulations supports the Stacker compression algorithm. PPP and LAPB encapsulations support both predictor and Stacker compression algorithms.

MPPC Compression

The compress command using the mppc and ignore-pfc options support compression between Cisco  routers and access servers and Microsoft clients, such as Windows 95 and Windows NT. MPPC implements an LZ-based compression algorithm that uses a compression dictionary to compress PPP packets. The ignore-pfc keyword instructs the router to ignore the protocol field compression flag negotiated by LCP. For example, the standard protocol field value for IP is 0x0021 when compression is disabled and 0x21 when compression is enabled. When the ignore-pfc option is enabled, the router will continue to use the uncompressed value (0x0021). Using the ignore-pfc option is helpful for some asynchronous driver devices that use an uncompressed protocol field (0x0021), even though the pfc is negotiated between peers. If protocol rejects are displayed when the debug ppp negotiation command is enabled, setting the ignore-pfc option may remedy the problem.

HDLC Encapsulations

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.

Public Data Network Connections

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.

Cisco 7200 and Cisco 7500 Series

Using CSA hardware compression on Cisco 7200 series routers and Cisco 7500 series routers removes the compression and decompression responsibilities from the VIP2 or the main processor installed in the router. By using the compress stac command, the router determines the fastest compression method available on the router.

On Cisco 7200 series routers and Cisco 7500 series routers, hardware compression on the compression service adapter (CSA) is supported for PPP links. When using hardware compression on Cisco 7200 series routers with multiple CSAs, you can optionally specify which CSA is used by the interface to perform compression. If no CSA is specified, the router determines which CSA is used. On Cisco 7500 series routers, the router uses the CSA on the same VIP2 as the interface.

System Performance


Caution When compression is performed in software installed in the router's main processor, it might affect system performance significantly. We recommend that you disable compression if the CPU load exceeds 40 percent. To display the CPU load, use the show process cpu EXEC command.

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.

Table 4 provides general guidelines for deciding which compression type to select.

Table 4 Compression Guidelines

Situation
Compression Type to Use

Bottleneck is caused by the load on the router.

Predictor

Bottleneck is the result of line bandwidth or hardware compression on the CSA is available.

Stacker

Most files are already compressed.

None


Software compression makes heavy demands on the router's processor. The maximum compressed serial line rate depends on the type of Cisco router that you are using and which compression algorithm you specify. Table 5 shows a summary of the compressed serial line rates for software compression. The maximums shown in Table 5 apply to the "combined" serial compressed load on the router. For example, a Cisco 4000 series router could handle four 64-kbps lines using Stacker compression or one 256-kbps line. These maximums also assume that there is very little processor load on the router aside from compression. Lower these numbers when the router is required to do other processor-intensive tasks.

Table 5 Combined Compressed Serial Line Rates (Software Compression)

Compression Method
Cisco 1000 Series
Cisco 3000 Series
Cisco 4000 Series
Cisco 4500 Series
Cisco 4700 Series
Cisco 7000 Family

Stacker (kbps)

128

128

256

500

T1

256

Predictor (kbps)

256

256

500

T1

2xT1

500


Hardware compression can support a combined line rate of 16 Mbps.

Cisco recommends that you do not adjust the maximum transmission unit (MTU) for the serial interface and the LAPB maximum bits per frame (N1) parameter.


Note The best performance data compression algorithms adjust their compression methodology as they identify patterns in the data. To prevent data loss and support this adjustment process, the compression algorithm is run over LAPB to ensure that everything is sent in order, with no missing data and no duplicate data.



Note For information on configuring Frame Relay compression, refer to the "Configuring Frame Relay" chapter in the Cisco IOS Wide-Area Networking Configuration Guide.


Examples

The following example enables hardware compression and PPP encapsulation on serial interface 3/1/0.

Router(config)# interface serial 3/1/0
Router(config-if)# encapsulate ppp
Router(config-if)# compress stac

The following example enables predictor compression on serial interface 0 for a LAPB link:

Router(config)# interface serial 0
Router(config-if)# encapsulation lapb
Router(config-if)# compress predictor
Router(config-if)# mtu 1509
Router(config-if)# 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); we recommend that you do not change those LAPB parameters for Stacker compression:

Router(config)# interface serial 0
Router(config-if)# encapsulation lapb
Router(config-if)# compress predictor

The following example configures BRI interface 0 to perform MPPC:

Router(config)# interface BRI0
Router(config-if)# ip unnumbered ethernet0
Router(config-if)# encapsulation ppp
Router(config-if)# isdn spid1 5551234
Router(config-if)# dialer map ip 172.21.71.74 5551234
Router(config-if)# dialer-group 1
Router(config-if)# compress mppc

The following example configures asynchronous interface 1 to implement MPPC and ignore the protocol field compression flag negotiated by LCP:

Router(config)# interface async1
Router(config-if)# ip unnumbered ethernet0
Router(config-if)# encapsulation ppp
Router(config-if)# async default routing
Router(config-if)# async dynamic routing
Router(config-if)# async mode interactive
Router(config-if)# peer default ip address 172.21.71.74
Router(config-if)# compress mppc ignore-pfc

Related Commands

Command
Description

encapsulation

Sets the encapsulation method used by the interface.

encapsulation x25

Specifies operation of a serial interface as an X.25 device.

exec

Allows an EXEC process on a line.

show compress

Displays compression statistics.

show processes

Displays information about the active processes.


compress mppc

To configure compression using the Microsoft Point-to-Point Compression (MPPC) algorithm on your data compression Advanced Interface Module (AIM) for the Cisco 2600 series router, use the compress mppc command in interface configuration mode. To disable MPPC compression, use the no form of this command.

compress mppc

no compress mppc

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Interface configuration

Command History

Release
Modification

12.0(1)T

This command was introduced.


Usage Guidelines

The MPPC compression algorithm is used to exchange compressed information with a Microsoft NT remote access server.

When configuring PPP on a serial interface, you can use hardware compression on the data compression AIM daughter card for MPPC if one is installed; otherwise you can use software compression.

Examples

The following example shows how to configure the data compression AIM daughtercard for MPPC:

Router(config-if)# encapsulate ppp
Router(config-if)# compress mppc

Related Commands

Command
Description

clear aim

Clears data compression AIM registers and resets the hardware.

compress stac caim

Specifies the exact hardware compression resource preferred.

encapsulation

Sets the encapsulation method used by the interface.

show compress

Displays compression statistics.

show pas caim

Displays debug information about the data compression AIM daughtercard.

show processes

Displays information about the active processes.


compress stac caim

To specify the hardware compression, use the compress stac caim command in interface configuration mode. To disable compression, use the no form of this command.

compress stac caim interface-number

no compress stac caim interface-number

Syntax Description

interface-number

Interface on which compression is enabled. AIM interfaces begin with 0.


Defaults

Disabled

Command Modes

Interface configuration

Command History

Release
Modification

12.0(1)T

This command was introduced.


Usage Guidelines

Hardware Compression

If the router contains a data compression Advanced Interface Module (CAIM), compression is performed in the CAIM hardware.

Using hardware compression in the AIM frees the main processor of the router for other tasks. You can also configure the router to use the Compression Port Module to perform compression by using the distributed option or to use the router's main processor by using the software option. If the Compression Port Module compression is performed in the main processor of the router.

Software Compression

If the CAIM is not available, compression is performed in the main processor of the router.

When compression is performed by the software installed in the router's main memory, system performance might be affected significantly. It is recommended that you disable compression in the main processor if the router CPU load exceeds 40 percent. To display the CPU load, use the show process cpu command in EXEC mode.

Examples

The following example specifies that hardware compression should be activated for CAIM interface 0:

Router(config-if)# encapsulation ppp
Router(config-if)# compress stac caim 0

Related Commands

Command
Description

clear aim

Clears data compression AIM registers and resets the hardware.

encapsulation

Sets the encapsulation method used by the interface.

show compress

Displays compression statistics.

show pas caim

Displays debug information about the data compression AIM daughtercard.


controller

To configure a T1, E1, or J1 controller and enter controller configuration mode, use the controller command in global configuration mode.

Cisco 2600 and 3600 Series Routers

controller {t1 | e1 | j1} slot/port

Cisco 7200 Series and Cisco 7500 Series Routers

controller {t1 | e1} slot/port

Cisco AS5300 Access Servers

controller {t1 | e1} number

Cisco AS5800 Access Servers

controller t1 dial-shelf/slot/t3-port:t1-num

Syntax Description

t1

T1 controller.

e1

E1 controller.

j1

J1 controller.

slot/port

Backplane slot number and port number on the interface. Refer to your hardware installation manual for the specific values and slot numbers.

number

Network processor module (NPM) number, in the range 0 through 2.

dial-shelf

Dial shelf chassis in the Cisco AS5800 access server that contains the interface card.

/t3-port

T3 port number. The only valid value is 0.

:t1-num

T1 timeslot in the T3 line. The value can be from 1 to 28.


Defaults

No T1, E1, or J1 controller is configured.

Command Modes

Global configuration

Command History

Release
Modification

10.0

This command was introduced.

10.3

The e1 keyword was added.

12.0(3)T

Support was added for dial shelves on Cisco AS5800 access servers.

12.2(7)XO

The j1 keyword was added for the Cisco 2600 and Cisco 3600 series.


Usage Guidelines

T1 or E1 Fractional Data Lines

This command is used in configurations where the router or access server is intended to communicate with a T1 or E1 fractional data line. Additional parameters for the T1 or E1 line must be configured for the controller before the T1 or E1 circuits can be configured by means of the interface global configuration command.

To view the status of the controllers use the show controllers command.

Examples

Cisco 7500 Series Router As a T1 Controller

The following example configures the MIP in slot 4, port 0 of a Cisco 7500 series router as a T1 controller:

Router(config)# controller t1 4/0
Router(config-controller)#

Cisco AS5800 Access Server with Dial Shelf

The following example configures the T1 controller in shelf 1, slot 0, port 0:

Router(config)# controller t1 1/0/0:1
Router(config-controller)#

Cisco 3660 As a J1 Controller

The following example configures the Cisco IOS interface card in slot 3, port 0 of a Cisco 3660 as a J1 controller:

Router(config)# controller j1 3/0
Router(config-controller)#

Related Commands

Command
Description

bert abort

Resets the T1 or E1 controller.

interface serial

Specifies a serial interface created on a channelized E1 or channelized T1 controller (for ISDN PRI, CAS, or robbed-bit signaling).

show controllers content-engine

Displays information about the E1 links supported by the NPM
(Cisco 4000) or MIP (Cisco 7500 series).

show controllers j1

Displays information about the J1 link.

show controllers t1

Displays the total number of calls and call durations on a T1 controller.


controller e3

To configure an E3 controller and enter controller configuration mode, use the controller e3 command in global configuration mode.

controller e3 slot/port

Syntax Description

slot/port

Number of the slot and port being configured. Refer to the appropriate hardware manual for slot and port information. The slash mark is required.


Defaults

No E3 controller is configured.

Command Modes

Global configuration

Command History

Release
Modification

11.1

This command was introduced.

12.2(11)YT

This command was integrated into Cisco IOS Release 12.2(11)YT and implemented on the following platforms: Cisco 2650XM, Cisco 2651XM, Cisco 2691, Cisco 3660 series, Cisco 3725, and Cisco 3745 routers.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Examples

The following example shows the E3 controller configured in slot 0, port 0:

Router(config)# controller e3 0/0
Router(config-controller)#

Related Commands

Command
Description

controller t3

Configures a T3 controller and enters controller configuration mode.

show controllers e3

Displays information about E3 controllers.

show controllers t3

Displays information about T3 controllers.


controller sonet

To configure a SONET controller and enter controller configuration mode, use the controller sonet command in global configuration mode.

controller sonet slot/port

Syntax Description

slot

Physical slot number. The slot number is in a range either from 0 to 5 or 8 to 13, depending on the slot in which the STM-1 card resides.

/port

SONET port number. The port number is always 0 because only one STM-1 port is supported per interface. The slash mark is required.


Defaults

port: 0

Command Modes

Global configuration

Command History

Release
Modification

12.0(14)S

This command was introduced.

12.2(15)T

This command was integrated into Cisco IOS Release 12.2(15)T.


Usage Guidelines

This command does not have a no form because the SONET controller is created automatically when the STM-1 trunk card is detected by the Cisco AS5850. Use this command to specify which slot number the STM-1 card is plugged into and to configure different attributes under controller configuration mode.

Examples

The following example shows how to specify that the SONET controller is in slot number 2:

Router(config)# controller sonet 2/0
Router(config-controller)#

Related Commands

Command
Description

show controllers sonet

Displays information about SONET controllers.


controller t3

To configure the Channelized T3 Interface Processor (CT3IP) in Cisco 7500 series routers or the CT3 feature board in Cisco AS5800 access servers, use the controller t3 command in global configuration mode. To delete the defined controller, use the no form of this command.

Cisco 7500 Series

controller t3 slot/port-adapter/port

no controller t3 slot/port-adapter/port

Cisco AS5800 Access Server

controller t3 dial-shelf/slot/t3-port

no controller t3 dial-shelf/slot/t3-port

Syntax Description

slot

Number of the slot being configured. Refer to the appropriate hardware manual for slot and port information./

/port-adapter

Number of the port adapter being configured. Refer to the appropriate hardware manual for information about port adapter compatibility.

/port

Number of the port being configured. Refer to the appropriate hardware manual for slot and port information.

dial-shelf

Dial shelf chassis in the Cisco AS5800 access server containing the CT3 interface card.

/slot

Location of the CT3 interface card in the dial shelf chassis.

/t3-port

T3 port number. The only valid value is 0.


Defaults

Cisco 7500 Series

No T3 controller is configured.

Cisco AS5800 Access Server

No default behavior or values.

Command Modes

Global configuration

Command History

Release
Modification

11.3

This command was introduced.

12.0(3)T

This command was implemented on the Cisco AS5800 access server.


Usage Guidelines

This command is used to configure the CT3IP and the 28 T1 channels. After the T1 channels are configured, continue to configure each T1 channel as a serial interface by using the interface serial global configuration command

Examples

Cisco 7500 Series

The following example configures the CT3IP in slot 3:

Router(config)# controller t3 3/0/0

Cisco AS5800 Access Server

The following example configures the T3 controller in shelf 3, slot 0, port 0 and T1 time slot 1:

Router(config)# controller t3 3/0/0

Related Commands

Command
Description

controller

Configures a T1, E1, or J1 controller and enters controller configuration mode.

interface

Specifies a serial interface created on a channelized E1 or channelized T1 controller (for ISDN PRI, CAS, or robbed-bit signaling).


crc

To set the length of the cyclic redundancy check (CRC) on a Fast Serial Interface Processor (FSIP) or HSSI Interface Processor (HIP) of the Cisco 7500 series routers or on a 4-port serial adapter of the Cisco 7200 series routers, use the crc command in interface configuration mode. To set the CRC length to 16 bits, use the no form of this command.

crc size

no crc

Syntax Description

size

CRC size in bits. Valid values are 16 and 32. The default is 16.


Defaults

16 bits

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

All interfaces use a 16-bit CRC by default, but also support a 32-bit CRC. CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The designators 16 and 32 indicate the length (in bits) of the frame check sequence (FCS). A CRC of 32 bits provides more powerful error detection, but adds overhead. Both the sender and receiver must use the same setting.

CRC-16, the most widely used throughout the United States and Europe, is used extensively with WANs. CRC-32 is specified by IEEE 802 and as an option by some point-to-point transmission standards. It is often used on Switched Multimegabit Data Service (SMDS) networks and LANs.

Examples

The following example enables the 32-bit CRC on serial interface 3/0:

Router(config)# interface serial 3/0
Router(config-if)# crc 32

crc4

To enable generation of CRC4 (per ITU Recommendation G.704 and G.703) to improve data integrity, use the crc4 command in interface configuration mode. To disable this function, use the no form of this command.

crc4

no crc4

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Interface configuration

Command History

Release
Modification

10.3

This command was introduced.

11.1 CA

This command was implemented on the Cisco 7200 series router and the E1-G.703/G.704 serial port adapter.


Usage Guidelines

This command applies to the Cisco 7200 series, Cisco 7000 series, and Cisco 7500 series routers. This command is supported on the Fast Serial Interface Processor (FSIP) and the E1-G.703/G.704 serial port adapter.

This command is useful for checking data integrity while operating in framed mode. CRC4 provides additional protection for a frame alignment signal under noisy conditions. For data transmission at E1 (2.048 Mbps), the G.704 standard suggests 4 bits CRC. Refer to CCITT Recommendation G.704 for a definition of CRC4.

You can also use the crc command to set the CRC size for the High-Level Data Link Control (HDLC) controllers.

Examples

The following example enables CRC4 generation on the E1-G.703/G.704 serial port adapter and also sets the CRC size to 32 bits:

Router(config)# interface serial 0/0
Router(config-if)# crc 32
Router(config-if)# crc4

Related Commands

Command
Description

crc

Sets the length of the CRC.


crc bits 5

To enable generation of CRC5 (per ITU Recommendation G.704 and G.703) to improve data integrity, use the crc bits 5 command in interface configuration mode. To disable this function, use the no form of this command.

crc bits 5

no crc bits 5

Syntax Description

This command has no arguments or keywords.

Defaults

CRC5 checking is disabled.

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CA

This command was introduced.


Usage Guidelines

This command is available for the JT2 6.3-MHz serial port adapter (PA-2JT2) on the second-generation Versatile Interface Processor (VIP2), in Cisco 7500 series routers, and in Cisco 7000 series routers with the Cisco 7000 series Route Switch Processor (RSP7000) and the Cisco 7000 series Chassis Interface (RSP7000CI).

This command is useful for checking data integrity while operating in framed mode. CRC5 provides additional protection for a frame alignment signal under noisy conditions. For data transmission at JT2 (6.312 Mbps), the G.704 standard suggests 5 bits CRC. Refer to ITU Recommendation G.704 for a definition of CRC5.

You can also use the crc command to set the CRC size for the High-Level Data Link Control (HDLC) controllers.

Examples

The following example enables CRC5 generation on the PA-2JT2 port adapter and also sets the CRC size to 32 bits:

Router(config)# interface serial 0/0
Router(config-if)# crc 32
Router(config-if)# crc bits 5

Related Commands

Command
Description

crc

Sets the length of the CRC.


cut-through

To configure the interfaces on the PA-12E/2FE port adapter to use cut-through switching technology between interfaces within the same bridge group, use the cut-through command in interface configuration mode. To return each interface to store-and-forward switching, use the no form of this command.

cut-through [receive | transmit]

no cut-through

Syntax Description

receive

(Optional) Selects cut-through switching technology on received data.

transmit

(Optional) Selects cut-through switching technology on transmitted data.


Defaults

Store-and-forward switching technology (that is, no cut-through)

Command Modes

Interface configuration

Command History

Release
Modification

11.2 P

This command was introduced.


Usage Guidelines

Cut-through mode allows switched packets to be transmitted after 64 bytes are received. The transmission of the packets can start before the end of the packet arrives. This reduces the time spent in the switch, but allows packets to be transmitted with bad cyclical redundancy checks (CRCs), because the transmission is initiated before the CRC is received or checked. Store-and-forward mode waits for the entire packet to be received before that packet is forwarded, but will check the CRC before starting transmission.

The PA-12E/2FE port adapter offloads Layer 2 switching from the host CPU by using store-and-forward or cut-through switching technology between interfaces within the same VLAN on the PA-12E/2FE port adapter. The PA-12E/2FE port adapter supports up to four VLANs (bridge groups).

Examples

The following example configures interface 3/0 for cut-through switching:

Router(config)# interface fastethernet 3/0
Router(config-if)# bridge-group 10
Router(config-if)# cut-through
Router(config-if)# no shutdown
Router(config-if)# exit