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Cisco IOS Interface and Hardware Component Command Reference, Release 12.3 T
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Introduction
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Interface and Hardware Component Commands: A through C
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Interface and Hardware Component Commands: D through H
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Interface and Hardware Component Commands: I through L
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int_m1gt_1
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Interface and Hardware Component Commands: M through R
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Interface and Hardware Component Commands: scramble through show chassis
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Interface and Hardware Component Commands: show compress through show hub
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Interface and Hardware Component Commands: show interfaces through show interfaces vg-anylan
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Interface and Hardware Component Commands: show ipc through syscon source-interface
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Interface and Hardware Component Commands: T through Y
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Table Of Contents
loopback (PA-MC-8TE1+ port adapter)
id aa-group
To configure the asynchronous acknowledgement group ID, use the id aa-group command in satellite initial configuration mode. To remove the ID configuration, use the no form of this command.
id aa-group number
no id aa-group
Syntax Description
Defaults
No default behavior or values
Command Modes
Satellite initial configuration
Command History
Usage Guidelines
This command is typically used by an installation technician. Do not use this command unless your satellite service provider instructs you to perform the satellite initial configuration and provides all necessary parameter values.
Examples
The following example shows how to configure the asynchronous acknowledgement group identification number:
Router(sat-init-config)# id aa-group 336id software group
To configure the operational software group identification number, use the id software group command in satellite initial configuration mode. To remove the ID configuration, use the no form of this command.
id software group number
no id software group
Syntax Description
Defaults
No default behavior or values
Command Modes
Satellite initial configuration
Command History
Usage Guidelines
This command is typically used by an installation technician. Do not use this command unless your satellite service provider instructs you to perform the satellite initial configuration and provides all necessary parameter values.
Examples
The following example shows how to configure the operational software group identification number:
Router(sat-init-config)# id software group 598id vsat
To configure the component physical address (CPA), use the id vsat command in satellite initial configuration mode. To remove the CPA configuration, use the no form of this command.
id vsat number
no id vsat number
Syntax Description
Defaults
No default behavior or values
Command Modes
Satellite initial configuration
Command History
Usage Guidelines
The CPA uniquely identifies the VSAT endpoint in the satellite network.
Note
This command is typically used by an installation technician. Do not use this command unless your satellite service provider instructs you to perform the satellite initial configuration and provides all necessary parameter values.
Examples
The following example shows how to configure the CPA number:
Router(sat-init-config)# id vsat 1284idle-pattern
To define the idle pattern that a circuit emulation (CEM) channel transmits when the channel experiences an underrun condition or to replace any missing packets, use the idle-pattern command in CEM configuration mode. To stop sending idle pattern data, use the no form of this command.
idle-pattern {pattern | length pattern1 [pattern2]}
no idle-pattern
Syntax Description
Defaults
For T1 or E1 channels: 0xFF.
For serial channels: 8 bits and 0xFF.Command Modes
CEM configuration
Command History
Usage Guidelines
Idle pattern data is always sent in multiples of one entire packet payload. If a single packet is missing from the arriving data stream it is replaced by an idle packet of the same payload size and composed of repetitions of the specified idle pattern. If the CEM channel outbound (egress) buffer experiences an underrun condition, identical idle packets are transmitted until the dejitter buffer is filled to at least half its total depth.
Examples
The following example shows how to configure a 32-bit idle pattern for a serial CEM channel.
Router(config-cem)# idle-pattern 32 0x12345678
Related Commands
cem
Enters circuit emulation configuration mode.
clear cem
Clears CEM channel statistics.
show cem
Displays CEM channel statistics.
ids-service-module monitoring
To enable Intrusion Detection System (IDS) monitoring on a specified interface, use the ids-service-module monitoring command in interface configuration mode. To perform IDS monitoring, the routing device must have a Cisco IDS network module installed. To disable IDS monitoring, use the no form of this command.
ids-service-module monitoring
no ids-service-module monitoring
Syntax Description
This command has no arguments or keywords.
Defaults
IDS monitoring is not enabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the ids-service-module monitoring command to enable IDS monitoring on a specified interface or subinterface. Both inbound and outbound packets on the specified interface are forwarded for monitoring.
The Cisco IDS network module is also referred to as the NM-CIDS.
Examples
The following example shows how to configure Fast Ethernet interface 0/0 to copy network traffic to the Cisco IDS network module and enable IDS monitoring:
Router(config)# interface FastEthernet0/0Router(config-if)# ids-service-module monitoringRelated Commands
service-module ids-sensor
Reboots, resets, enables console access to, shuts down, and monitors the status of the Cisco IDS network module.
ignore (interface)
To configure the serial interface to ignore the specified serial signals as the line up/down indicator, use the ignore command in interface configuration mode. To restore the default, use the no form of this command.
DCE Asynchronous Mode
ignore [dtr | rts]
no ignore [dtr | rts]
DCE Synchronous Mode
ignore [dtr | local-loopback | rts]
no ignore [dtr | local-loopback | rts]
DTE Asynchronous Mode
ignore [cts | dsr]
no ignore [cts | dsr]
DTE Synchronous Mode
ignore [cts | dcd | dsr]
no ignore [cts | dcd | dsr]
Syntax Description
Defaults
The no form of this command is the default. The serial interface monitors the serial signal as the line up/down indicator.
Command Modes
Interface configuration
Command History
Usage Guidelines
Serial Interfaces in DTE Mode
When the serial interface is operating in DTE mode, it monitors the DCD signal as the line up/down indicator. By default, the attached DCE device sends the DCD signal. When the DTE interface detects the DCD signal, it changes the state of the interface to up.
SDLC Multidrop Environments
In some configurations, such as a Synchronous Data Link Control (SDLC) multidrop environment, the DCE device sends the DSR signal instead of the DCD signal, which prevents the interface from coming up. Use this command to tell the interface to monitor the DSR signal instead of the DCD signal as the line up/down indicator.
Examples
The following example shows how to configure serial interface 0 to ignore the DCD signal as the line up/down indicator:
Router(config)# interface serial 0Router(config-if)# ignore dcdRelated Commands
debug serial lead-transition
Activates the leads status transition debug capability for all capable ports.
show interfaces serial
Displays information about a serial interface.
ignore-dcd
To configure the serial interface to monitor the Data Set Ready (DSR) signal instead of the Data Carrier Detect (DCD) signal as the line up/down indicator, use the ignore-dcd command in interface configuration mode. To restore the default, use the no form of this command.
ignore-dcd
no ignore-dcd
Syntax Description
This command has no arguments or keywords.
Defaults
The serial interface, operating in DTE mode, monitors the DCD signal as the line up/down indicator.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command applies to Quad Serial NIM interfaces on the Cisco 4000 series routers and Hitachi-based serial interfaces on the Cisco 2500 and Cisco 3000 series routers.
Serial Interfaces in DTE Mode
When the serial interface is operating in DTE mode, it monitors the DCD signal as the line up/down indicator. By default, the attached DCE device sends the DCD signal. When the DTE interface detects the DCD signal, it changes the state of the interface to up.
SDLC Multidrop Environments
In some configurations, such as an Synchronous Data Link Control (SDLC) multidrop environment, the DCE device sends the DSR signal instead of the DCD signal, which prevents the interface from coming up. Use this command to tell the interface to monitor the DSR signal instead of the DCD signal as the line up/down indicator.
Examples
The following example shows how to configure serial interface 0 to monitor the DSR signal as the line up/down indicator:
Router(config)# interface serial 0Router(config-if)# ignore-dcdignore-error-duration
To ignore initial train-up errors when the DSL controller is connected to DSLAMs with chipsets other than Globespan, use the ignore-error-duration command in controller configuration mode. To set the error duration to the default of 0 seconds, use the no form of the command.
ignore-error-duration seconds
Syntax Description
seconds
Sets the time in seconds for which errors will be ignored during training of the line. Range is from 15 to 30 seconds.
Defaults
0 seconds
Command Modes
Controller configuration
Command History
Usage Guidelines
This command is used to ignore initial train-up errors when connected to DSLAMs with chipsets other than Globespan. Use the time period of 15 to 30 seconds to allow the line to train without being affected by errors that result because of the line training.
Examples
The following example sets the time during which errors will be ignored to 15 seconds:
Router(config)# controller dsl 4/0Router(config-controller)# ignore-error-duration 15Related Commands
ignore-hw local-loopback
To disable the monitoring of the (local-loopback) LL pin when in DCE mode, use the ingnore-hw local-loopback command in interface configuration mode. To enable the monitoring of the LL pin, use the no form of this command.
ignore-hw local-loopback
no ignore-hw local-loopback
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command if your system is experiencing spurious modem interrupts that momentarily cause the interface to enter loopback mode. The end result of this behavior is the loss of Synchronous Data Link Control (SDLC) Logical Link Control (SDLLC) sessions.
Note
Examples
The following example shows how to disable the monitoring of the LL pin when in DCE mode:
Router(config)# interface serial 2Router(config-if)# ignore-hw local-loopbackinterface
To configure an interface type and enter interface configuration mode, use the interface command in global configuration mode.
Standard Syntax
interface type number [name-tag]
Cisco 7200 Series and Cisco 7500 Series with a Packet over SONET Interface Processor
interface type slot/port
Cisco 7200 VXR Router used as a Router Shelf in an AS5800 Universal Access Server
interface type router-shelf/slot/port
Cisco 7500 Series with Channelized T1 or E1
interface serial slot/port:channel-group
Cisco 7500 Series with Ports on VIP Cards
interface type slot/port-adapter/port
Content Engine Network Module
interface content-engine slot/unit
Satellite Network Module
interface satellite slot/unit
Service Engine Network Module or Advanced Integration Module (AIM)
interface service-engine slot/port
To configure a subinterface, use this form of the interface global configuration command.
Cisco 7200 Series
interface type slot/port.subinterface-number [multipoint | point-to-point]
Cisco 7500 Series
interface type slot/port-adapter.subinterface-number [multipoint | point-to-point]
Cisco 7500 Series with Ports on VIP Cards
interface type slot/port-adapter/port.subinterface-number [multipoint | point-to-point]
Syntax Description
type
Type of interface to be configured. See Table 11.
number
Port, connector, or interface card number. On Cisco 4700 series routers, specifies the network interface module (NIM) or network processor module (NPM) number. The numbers are assigned at the factory at the time of installation or when added to a system, and can be displayed with the show interfaces command.
name-tag
(Optional) Specifies the logic name to identify the server configuration so that multiple entries of server configuration can be entered.
This optional argument is for use with the Redundant Link Manager (RLM) feature.
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.
router-shelf
Router shelf number in a Cisco AS5800 universal access server. Refer to the appropriate hardware manual for slot and port information.
:channel-group
Channel group number. Cisco 7500 series routers specify the channel group number in the range of 0 to 4 defined with the channel-group controller configuration command.
/port-adapter
Port adapter number. Refer to the appropriate hardware manual for information about port adapter compatibility.
/unit
Number of the daughter card on the network module.
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.subinterface-number
Subinterface number in the range 1 to 4,294,967,293. The number that precedes the period (.) must match the number to which this subinterface belongs.
multipoint | point-to-point
(Optional) Specifies a multipoint or point-to-point subinterface. There is no default.
Defaults
No interface types are configured.
Command Modes
Global configuration
Note
Command History
Usage Guidelines
Subinterfaces can be configured to support partially meshed Frame Relay networks. Refer to the "Configuring Serial Interfaces" chapter in the Cisco IOS Interface and Hardware Component Configuration Guide.
This command does not have a no form.
Using the group-async Keyword
Using the group-async keyword, you create a single asynchronous interface to which other interfaces are associated as members using the group-range command. This one-to-many configuration allows you to configure all associated member interfaces by entering one command on the group master interface, rather than entering this command on each individual interface. You can create multiple group masters on a device; however, each member interface can be associated only with one group.
Using the port-channel Keyword
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. You can configure the port-channel interface as you would do to any Fast Ethernet interface.
After you create a port-channel interface, you assign Fast Ethernet interfaces (up to four) to it. For information on how to assign a Fast Ethernet interface to a port-channel interface, refer to the channel-group interface configuration command.
Caution
Caution
As you work with the port-channel keyword, consider the following points:
•
•
Using the vg-anylan Keyword
The 100VG-AnyLAN port adapter provides a single interface port that is compatible with and specified by IEEE 802.12. The 100VG-AnyLAN port adapter provides 100 Mbps over Category 3 or Category 5 unshielded twisted-pair (UTP) cable with RJ-45 terminators, and supports IEEE 802.3 Ethernet packets.
You configure the 100VG-AnyLAN port adapter as you would any Ethernet or Fast Ethernet interface. The 100VG-AnyLAN port adapter can be monitored with the IEEE 802.12 Interface MIB.
Examples
Asynchronous Group Master Interface
The following example shows how to define asynchronous group master interface 0:
Router(config)# interface group-async 0Content Engine Network Module
The following example configures an interface for a content engine network module in slot 1:
Router(config)# interface content-engine 1/0Ethernet Port 4 on the Ethernet Interface Processor (EIP)
The following example shows how to configure Ethernet port 4 on the Ethernet Interface Processor (EIP) in slot 2 on the Cisco 7500 series router:
Router(config)# interface ethernet 2/4Fast Ethernet
The following example shows how to configure Fast Ethernet interface 0 for standard ARPA encapsulation (the default setting) on a Cisco 4700 series router:
Router(config)# interface fastethernet 0Gigabit Ethernet
The following example shows how to configure Gigabit Ethernet interface for slot 0, port 0:
Router(config)# interface gigabitethernet 0/0Loopback Mode
The following example shows how to enable loopback mode and assigns an IP network address and network mask to the interface. The loopback interface established here will always appear to be up:
Router(config)# interface loopback 0Router(config-if)# ip address 10.108.1.1 255.255.255.0Packet OC-3
The following example shows how to specify the single Packet OC-3 interface on port 0 of the POS OC-3 port adapter in slot 2:
Router(config)# interface pos 2/0/0Partially Meshed Frame Relay Network
The following example shows how to configure a partially meshed Frame Relay network. In this example, subinterface serial 0.1 is configured as a multipoint subinterface with three associated Frame Relay permanent virtual connections (PVCs), and subinterface serial 0.2 is configured as a point-to-point subinterface.
Router(config)# interface serial 0Router(config-if)# encapsulation frame-relayRouter(config-if)# exitRouter(config)# interface serial 0/0.1 multipointRouter(config-if)# ip address 10.108.10.1 255.255.255.0Router(config-if)# frame-relay interface-dlci 42 broadcastRouter(config-if)# frame-relay interface-dlci 53 broadcastRouter(config-if)# exitRouter(config)# interface serial 0/0.2 point-to-pointRouter(config-if)# ip address 10.108.11.1 255.255.0Router(config-if)# frame-relay interface-dlci 59 broadcastPort Channel in Channel Group
The following example shows how to create a port-channel interface with a channel group number of 1 and adds two Fast Ethernet interfaces to port-channel 1:
Router(config)# interface port-channel 1Router(config-if)# ip address 10.1.1.10 255.255.255.0Router(config-if)# exitRouter(config)# interface fastethernet 1/0/0Router(config-if)# channel-group 1Router(config-if)# exitRouter(config)# interface fastethernet 4/0/0Router(config-if)# channel-group 1PPP Encapsulation
The following example shows how to configure serial interface 0 with PPP encapsulation:
Router(config)# interface serial 0Router(config-if)# encapsulation pppSatellite Interface Configuration
The following example shows how to enter satellite interface configuration mode:
Router(config)# interface satellite 1/0Router(config-if)#Service Engine for NM or AIM
The following example shows the command for entering interface configuration mode for either an NM or an AIM located in slot 1, unit 1:
Router (config)# interface service-engine 1/1Router (config-if)# exitT1 Link for Point-to-Point (PPP)
The following example shows how to configure circuit 0 of a T1 link for Point-to-Point Protocol (PPP) encapsulation:
Router(config)# controller t1 4/1Router(config-controller)# circuit 0 1Router(config-controller)# exitRouter(config)# interface serial 4/1:0Router(config-if)# ip address 10.108.13.1 255.255.255.0Router(config-if)# encapsulation pppToken Ring Interface Processor
The following example shows how to configure the Token Ring interface processor in slot 1 on port 0 of a Cisco 7500 series routers:
Router(config)# interface tokenring 1/0Related Commands
interface analysis-module
To configure the Analysis-Module interface on the router that connects to an installed Network Analysis Module (NM-NAM), use the interface analysis-module command in global configuration mode. This command does not have a not form.
interface analysis-module slot/unit
Syntax Description
Defaults
The interface is not configured.
Command Modes
Global configuration
Command History
Usage Guidelines
The Analysis-Module interface is a Fast Ethernet interface on the router that connects to the internal interface on the Network Analysis Module (NM-NAM).
This type of interface cannot be configured for subinterfaces or for speed, duplex mode, and similar parameters. See the command-line interface (CLI) help for a list of valid parameters.
The interface analysis-module command enters Analysis-Module interface configuration mode.
Examples
The following example shows how to configure the Analysis-Module interface when the NM-NAM is in router slot 1:
Router(config)# interface analysis-module 1/0Related Commands
interface content-engine
The interface content-engine command is now documented as the content-engine keyword of the interface command. For more information, see the interface command.
interface fastethernet
The interface fastethernet command is now documented as the fastethernet keyword of the interface command. For more information, see the interface command.
interface gigabitethernet
The interface gigabitethernet command is now documented as the gigabitethernet keyword of the interface command. For more information, see the interface command.
interface group-async
The interface group-async command is now documented as the group-async keyword of the interface command. For more information, see the interface command.
interface port-channel
The interface port-channel command is now documented as the port-channel keyword of the interface command. For more information, see the interface command.
interface pos
The interface pos command is now documented as the pos keyword of the interface command. For more information, see the interface command.
interface range
To execute commands on multiple subinterfaces at the same time, use the interface range command in global configuration command mode.
interface range {fastethernet interfacenumber - interfacenumber | gigabitethernet interfacenumber - interfacenumber | loopback number | tunnel number | port-channel number | vlan number | macro word}
Syntax Description
Defaults
No default behavior or values
Command Modes
Global configuration
Command History
Usage Guidelines
Configuration Changes
All configuration changes made to a range of subinterfaces are saved to NVRAM, but the range itself does not get savedto NVRAM. Use the define interface-range command to create and save a range.
You can enter the range in two ways:
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•
You can specify either the interfaces or the name of a range macro. A range must consist of the same interface type, and the interfaces within a range cannot span slots.
You cannot specify both an interface range and a macro keyword in the same command. After creating a macro, the CLI does not allow you to enter additional ranges. Likewise, if you have already entered an interface range, the CLI does not allow you to enter a macro.
The spaces around the dash in the interface range command syntax are required. For example, using a Catlyst 6500 router, the command interface range fastethernet 1 - 6 is valid; the command interface range fastethernet 1-6 is not valid.
VLAN Ranges
When you define a Catalyst Vlans, valid values are from 1 to 4094. The last VLAN number cannot exceed 4094.
You cannot use the interface range command to create switch virtual interfaces (SVIs). You must create SVIs with individual interface VLAN commands. You can use the interface range command on existing VLAN SVIs. To display VLAN SVIs, enter the show running-config command. VLANs not displayed cannot be used in the interface range command.
The commands entered under the interface range command are applied to all existing VLAN SVIs.
Examples
The following example shows how to use the interface range command to configure a fastethernet range:
Router(config)# interface range fastethernet5/1 - 4Router(config-if-range)#
The following example shows how to set a vlan:
Cisco-65K(config)#interface range vlan 123Cisco-65K(config-if-range)#The following example configures the Fast Ethernet subinterfaces within the range from 5/1.1 to 5/1.4 and applies the following VLAN IDs to those subinterfaces:
Fast Ethernet5/1.1 = VLAN ID 301 (vlan-id)Fast Ethernet5/1.2 = VLAN ID 302 (vlan-id = 301 + 2 - 1 = 302)Fast Ethernet5/1.3 = VLAN ID 303 (vlan-id = 301 + 3 - 1 = 303)Fast Ethernet5/1.4 = VLAN ID 304 (vlan-id = 301 + 4 - 1 = 304)Router(config)# interface range fastethernet5/1 - 4Router(config-if)# encapsulation dot1q 301Router(config-if)# no shutdownRouter(config-if)#*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.1, changed state to up*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.2, changed state to up*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.3, changed state to up*Oct 6 08:24:35: %LINK-3-UPDOWN: Interface FastEthernet5/1.4, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.1, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.2, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.3, changed state to up*Oct 6 08:24:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet5/1.4, changed state to upThe following example shows how to execute a range macro:
Router(config)# interface range macro macro1The following exampe shows how to set a gigabitethernet range:
Router(config)# interface range gigabitethernet1/1 - 6Router(config-if-range)#
The following example shows how to use the loopback interface:
Router(config)# interface range loopback 34567Router(config-if-range)#
The following example shows how to use the tunnel interface:
Router(config)# interface range tunnel 55555Router(config-if-range)#
The following example shows how to use the port-channel interface:
Router(config)# interface range port-channel 343Router(config-if-range)#
Related Commands
interface service-engine
To enter the interface configuration mode for a network module (NM) or an advanced Integration Module (AIM), use the interface service-engine command in global configuration mode.
interface service-engine slot/port
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
12.2(15)ZJ
This command was introduced for NMs.
12.3(4)T
This command was integrated into Cisco IOS Release 12.3(4)T.
12.3(7)T
Support was added for AIMs.
Usage Guidelines
This command may only be used for NMs and AIMs. If your system does not have this hardware, then you will be unable to enter this command.
The no form of this command (no interface service-engine) is not available. The exit command can be used to exit the interface configuration mode.
Examples
The following example shows the command for entering configuration mode for either a NM or AIM located in slot 1, unit 1:
Router (config)# interface service-engine 1/1Router (config-if)# exitinterface vg-anylan
The interface vg-anylan command is now documented as the vg-anylan keyword of the interface command. For more information, see the interface command.
interface
To configure an interface type and enter interface configuration mode, use the interface command in global configuration mode.
Standard Syntax
interface type number [name-tag]
Analysis Module Network Module
interface analysis-module slot/unit
Content Engine Network Module
interface content-engine slot/unit
Cisco 7200 Series and Cisco 7500 Series with a Packet over SONET Interface Processor
interface type slot/port
Cisco 7200 VXR Router used as a Router Shelf in a Cisco AS5800 Universal Access Server
interface type router-shelf/slot/port
Cisco 7500 Series with Channelized T1 or E1
interface serial slot/port:channel-group
Cisco 7500 Series with Ports on VIP Cards
interface type slot/port-adapter/port
To configure a subinterface, use this form of the interface global configuration command.
Cisco 7200 Series
interface type slot/port.subinterface-number [multipoint | point-to-point]
Cisco 7500 Series
interface type slot/port-adapter.subinterface-number [multipoint | point-to-point]
Cisco 7500 Series with Ports on VIP Cards
interface type slot/port-adapter/port.subinterface-number [multipoint | point-to-point]
Syntax Description
type
Type of interface to be configured. See Table 11.
number
Port, connector, or interface card number. On Cisco 4700 series routers, specifies the network interface module (NIM) or network processor module (NPM) number. The numbers are assigned at the factory at the time of installation or when added to a system, and can be displayed with the show interfaces command.
name-tag
(Optional) Specifies the logic name to identify the server configuration so that multiple server configurations can be entered.
This optional argument is for use with the Redundant Link Manager (RLM) feature.
slot
Slot number. Refer to the appropriate hardware manual for slot information.
/unit
Number of the daughter card on the network module. For analysis module and content engine (CE) network modules, always use 0.
/port
Port number. Refer to the appropriate hardware manual for port information.
router-shelf
Router shelf number in a Cisco AS5800 universal access server. Refer to the appropriate hardware manual for router shelf information.
:channel-group
Channel group number. Cisco 7500 series routers specify the channel group number in the range of 0 to 4 defined with the channel-group controller configuration command.
/port-adapter
Port adapter number. Refer to the appropriate hardware manual for information about port adapter compatibility.
.subinterface-number
Subinterface number in the range 1 to 4294967293. The number that precedes the period (.) must match the number to which this subinterface belongs.
multipoint | point-to-point
(Optional) Specifies a multipoint or point-to-point subinterface. There is no default.
Defaults
No interface types are configured.
Command Modes
Global configuration
Note
Command History
Usage Guidelines
This command does not have a no form.
Subinterfaces can be configured to support partially meshed Frame Relay networks. Refer to the "Configuring Serial Interfaces" chapter in the Cisco IOS Interface and Hardware Component Configuration Guide.
Table 11 displays the keywords that represent the types of interfaces that can be configured with the interface command. Replace the type argument with the appropriate keyword from the table.
Using the analysis-module Keyword
The analysis module interface is used to access the NAM console for the initial configuration. After the NAM IP parameters are configured, the analysis module interface is typically used only during NAM software upgrades and while troubleshooting if the NAM Traffic Analyzer is inaccessible.
Visible only to the Cisco IOS software on the router, the analysis module interface is an internal Fast Ethernet interface on the router that connects to the internal NAM interface. The analysis module interface is connected to the router's Peripheral Component Interconnect (PCI) backplane, and all configuration and management of the analysis module interface must be performed from the Cisco IOS CLI.
Using the group-async Keyword
Using the group-async keyword, you create a single asynchronous interface with which other interfaces are associated as members using the group-range command. This one-to-many configuration allows you to configure all associated member interfaces by entering one command on the group master interface, rather than entering this command on each individual interface. You can create multiple group masters on a device; however, each member interface can be associated only with one group.
Using the port-channel Keyword
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. You can configure the port-channel interface as you would any Fast Ethernet interface.
After you create a port-channel interface, you assign Fast Ethernet interfaces (up to four) to it. For information on how to assign a Fast Ethernet interface to a port-channel interface, refer to the channel-group interface configuration command.
Caution
Fast Ethernet interfaces. Do not assign bridge groups on the physical Fast Ethernet interfaces
because it creates loops. Also, you must disable spanning tree.
Caution
ip route-cache distributed commands from the Fast Ethernet interfaces before enabling dCEF on
the port-channel interface. Clearing the route cache gives the port-channel interface proper control
of its physical Fast Ethernet links. When you enable CEF/dCEF globally, all interfaces that support CEF/dCEF are enabled. When CEF/dCEF is enabled on the port-channel interface, it is automatically enabled on each of the Fast Ethernet interfaces in the channel group. However, if you have
previously disabled CEF/dCEF on the Fast Ethernet interface, CEF/dCEF is not automatically
enabled. In this case, you must enable CEF/dCEF on the Fast Ethernet interface.
As you work with the port-channel keyword, consider the following points:
•
•
Using the vg-anylan Keyword
The 100VG-AnyLAN port adapter provides a single interface port that is compatible with and specified by IEEE 802.12. The 100VG-AnyLAN port adapter provides 100 Mbps over Category 3 or Category 5 unshielded twisted-pair (UTP) cable with RJ-45 terminators, and supports IEEE 802.3 Ethernet packets.
You configure the 100VG-AnyLAN port adapter as you would any Ethernet or Fast Ethernet interface. The 100VG-AnyLAN port adapter can be monitored with the IEEE 802.12 Interface MIB.
Examples
The following example shows how to configure serial interface 0 with PPP encapsulation:
Router(config)# interface serial 0Router(config-if)# encapsulation pppThe following example shows how to enable loopback mode and assigns an IP network address and network mask to the interface. The loopback interface established here will always appear to be up.
Router(config)# interface loopback 0Router(config-if)# ip address 10.108.1.1 255.255.255.0The following example shows how to configure Ethernet port 4 on the Ethernet Interface Processor (EIP) in slot 2 on the Cisco 7500 series router:
Router(config)# interface ethernet 2/4The following example shows how to configure the Token Ring interface processor in slot 1 on port 0 of a Cisco 7500 series router:
Router(config)# interface tokenring 1/0The following example configures an analysis module interface when the NAM router is in router slot 1:
Router(config)# interface analysis-module 1/0The following example configures an interface for a content engine network module in slot 1:
Router(config)# interface content-engine 1/0The following example shows how to configure Fast Ethernet interface 0 for standard ARPA encapsulation (the default setting) on a Cisco 4700 series router:
Router(config)# interface fastethernet 0The following example shows how to configure the Gigabit Ethernet interface for slot 0, port 0:
Router(config)# interface gigabitethernet 0/0The following example shows how to define asynchronous group master interface 0:
Router(config)# interface group-async 0The following example shows how to create a port-channel interface with a channel group number of 1 and adds two Fast Ethernet interfaces to port-channel 1:
Router(config)# interface port-channel 1Router(config-if)# ip address 10.1.1.10 255.255.255.0Router(config-if)# exitRouter(config)# interface fastethernet 1/0/0Router(config-if)# channel-group 1Router(config-if)# exitRouter(config)# interface fastethernet 4/0/0Router(config-if)# channel-group 1The following example shows how to specify the single Packet OC-3 interface on port 0 of the POS OC-3 port adapter in slot 2:
Router(config)# interface pos 2/0The following example shows how to specify the 100VG-AnyLAN port adapter in the first port adapter in slot 1:
Router(config)# interface vg-anylan 1/0/0The following example shows how to configure a partially meshed Frame Relay network. In this example, subinterface serial 0.1 is configured as a multipoint subinterface with two associated Frame Relay permanent virtual connections (PVCs), and subinterface serial 0.2 is configured as a point-to-point subinterface.
Router(config)# interface serial 0Router(config-if)# encapsulation frame-relayRouter(config-if)# exitRouter(config)# interface serial 0/0.1 multipointRouter(config-if)# ip address 10.108.10.1 255.255.255.0Router(config-if)# frame-relay interface-dlci 42 broadcastRouter(config-if)# frame-relay interface-dlci 53 broadcastRouter(config-if)# exitRouter(config)# interface serial 0/0.2 point-to-pointRouter(config-if)# ip address 10.108.11.1 255.255.255.0Router(config-if)# frame-relay interface-dlci 59 broadcastThe following example shows how to configure circuit 0 of a T1 link for PPP encapsulation:
Router(config)# controller t1 4/1Router(config-controller)# circuit 0 1Router(config-controller)# exitRouter(config)# interface serial 4/1:0Router(config-if)# ip address 10.108.13.1 255.255.255.0Router(config-if)# encapsulation pppRelated Commands
international bit
To set the E3 international bit in the G.751 frame used by the PA-E3 port adapter, use the international bit command in interface configuration mode. To return to the default international bit, use the no form of this command.
international bit {0 | 1} {0 | 1}
no international bit
Syntax Description
0
Sets either of the two required E3 international bits in the G.751 frame to 0. This is the default.
1
Sets either of the two required E3 international bits in the G.751 frame to 1.
Defaults
The default value for each bit is 0.
Command Modes
Interface configuration
Command History
Usage Guidelines
The international bit command sets bits 6 and 8, respectively, of set II in the E3 frame.
To verify the international bit configured on the interface, use the show controllers serial EXEC command.
Examples
The following example sets the international bit to 1 1 on the PA-E3 port adapter in slot 1, port adapter slot 0, interface 0:
Router(config)# interface serial 1/0/0Router(config-if)# international bit 1 1Related Commands
invert data
To invert the data stream, use the invert data command in interface configuration mode. This command applies only to the Cisco 7000 series routers with the RSP7000 and RSP7000CI, Cisco 7200 series routers, and Cisco 7500 series routers. To disable inverting the data stream, use the no form of this command.
invert data
no invert data
Syntax Description
This command has no arguments or keywords.
Defaults
Data is not inverted.
Command Modes
Interface configuration
Command History
11.1 CA
This command was introduced.
11.2 P
This command was integrated into Cisco IOS Release 11.2 P.
Usage Guidelines
T1 Line Without B8ZS Encoding
If the interface on the PA-8T and PA-4T+ synchronous serial port adapters and the PA-T3 and PA-2T3 synchronous serial port adapters is used to drive a dedicated T1 line that does not have B8ZS encoding (a method to avoid 15 zeros), the data stream must be inverted (both transmitting and receiving data) either in the connecting CSU/DSU or in the interface.
Inverting is a method of avoiding excessive zeroes that is superseded by the use of B8ZS encryption. This option could be needed for use with legacy equipment that supports this option. By inverting the High-Level Data Link Control (HDLC) data stream, the HDLC zero insertion algorithm becomes a ones insertion algorithm that satisfies the T1 requirements. Be careful not to invert data both on the interface and on the CSU/DSU because two data inversions will cancel each other out.
AMI Line Coding
If the interface on the CT3IP uses alternate mark inversion (AMI) line coding, you must also invert the data on the T1 channel. For more information, see the t1 linecode controller configuration command.
Examples
The following example inverts data on serial interface 3/1/0:
Router(config)# interface serial 3/1/0Router(config-if)# invert dataRelated Commands
t1 linecode
Specifies the type of linecoding used by the T1 channels on the CT3IP in Cisco 7500 series routers.
invert rxclock
To invert the phase of the receive (RX) clock signal on the universal I/O (UIO) serial interface that does not use the T1/E1 interface, use the invert rxclock command in interface configuration mode. To disable the phase inversion, use the no form of this command.
invert rxclock
no invert rxclock
Syntax Description
This command has no arguments or keywords.
Defaults
The receive clock signal is not inverted.
Command Modes
Interface configuration
Command History
Usage Guidelines
When a delay occurs between a signal being sent and the signal being received it can indicate that the receive clock signal is not appropriate for the interface rate. This command allows the receive clock signal to be inverted to attempt to correct the delay.
Examples
The following example inverts the receive clock signal on serial interface 1:
Router(config)# interface serial 1Router(config-if)# invert rxclockinvert txclock
To invert the transmit (TX) clock signal, use the invert txclock command in interface configuration mode. To return the TX clock signal to its initial state, use the no form of this command.
invert txclock
no invert txclock
Syntax Description
This command has no arguments or keywords.
Defaults
The transmit clock signal is not inverted.
Command Modes
Interface configuration
Command History
10.0
This command was introduced.
11.3
The invert-transmit-clock command was replaced by the invert txclock command.
Usage Guidelines
Delays between the serial clock transmit external (SCTE) clock and data transmission indicate that the TX clock signal might not be appropriate for the interface rate and length of cable being used. Different ends of the wire can have variances that differ slightly. The invert txclock command compensates for these variances. This command replaces the invert-transmit-clock command.
Systems that use long cables or cables that are not transmitting the TxC signal (transmit echoed clock line, also known as TXCE or SCTE clock) can experience high error rates when operating at the higher transmission speeds. For example, if a PA-8T synchronous serial port adapter is reporting a high number of error packets, a phase shift might be the problem. Inverting the clock might correct this shift.
When a PA-8T or PA-4T+ port adapter interface is DTE, the invert txclock command inverts the TxC signal it received from the remote DCE. When the PA-8T or PA-4T+ port adapter interface is DCE, this command changes the signal back to its original phase.
Examples
The following example inverts the TX clock signal on serial interface 3/0:
Router(config)# interface serial 3/0Router(config-if)# invert txclockip dscp
To enable the use of IP differentiated services code point (DSCP) for packets that originate from a circuit emulation (CEM) channel, use the ip dscp command in CEM configuration mode. To disable the use of IP DSCP, use the no form of this command.
ip dscp [dscp-value]
no ip dscp
Syntax Description
dscp-value
Value placed in the DSCP field of IP packets that originate from a CEM channel. Range is from 0 to 63. Default is 46.
Defaults
IP DSCP is enabled.
Command Modes
CEM configuration
Command History
Usage Guidelines
DSCP is mutually exclusive from both IP type of service (ToS) and IP precedence. Thus, if DSCP is configured, the ip tos command and the ip precedence command are both unavailable at the command-line interface (CLI).
Examples
The following example shows how to set the IP DSCP field value to 36.
Router(config-cem)# ip dscp 36Related Commands
ip precedence
Configures the IP precedence bits for the CEM channel.
ip tos
Configures the IP ToS bits for the CEM channel.
ipc zone default
To enter interprocess communication (IPC) zone configuration mode, use the ipc zone default command in global configuration mode. To remove a previously configured association, use the no form of this command.
ipc zone default
no ipc zone default
Syntax Description
This command has no arguments or keywords.
Command Default
The user is not in IPC zone configuration mode.
Command Modes
Global configuration
Command History
Usage Guidelines
The ipc zone default command places the router into IPC zone configuration mode. In this mode, the user can configure the default IPC zone.
The no form of the ipc zone default command removes any previously configured association.
Examples
The following example places the router into IPC zone configuration mode:
Router(config)# ipc zone defaultRouter(config-ipczone)#Related Commands
keepalive
To enable keepalive packets and to specify the number of times that the Cisco IOS software tries to send keepalive packets without a response before bringing down the interface or before bringing the tunnel protocol down for a specific interface, use the keepalive command in interface configuration mode. When the keepalive function is enabled, a keepalive packet is sent at the specified time interval to keep the interface active. To turn off keepalive packets entirely, use the no form of this command.
keepalive [period [retries]]
no keepalive [period [retries]]
Syntax Description
Defaults
period: 10 seconds
retries: 5
If you enter only the keepalive command with no arguments, defaults for both arguments are used.
If you enter only the keepalive command and the timeout parameter, the default number of retries (5) is used.
If you enter the no keepalive command, keepalive packets are disabled on the interface.Command Modes
Interface configuration
Command History
Usage Guidelines
Keepalive Time Interval
You can configure the keepalive time interval, which is the frequency at which the Cisco IOS software sends messages to itself (Ethernet and Token Ring) or to the other end (serial and tunnel), to ensure that a network interface is alive. The interval is adjustable in 1-second increments down to 1 second. An interface is declared down after three update intervals have passed without receiving a keepalive packet unless the retry value is set higher.
Note
Setting the keepalive timer to a low value is very useful for rapidly detecting Ethernet interface failures (transceiver cable disconnecting, cable not terminated, and so on).
Line Failure
A typical serial line failure involves losing Carrier Detect (CD) signal. Because this sort of failure is typically noticed within a few milliseconds, adjusting the keepalive timer for quicker routing recovery is generally not useful.
Keepalive Packets with Tunnel Interfaces
GRE keepalive packets may be sent from both sides of a tunnel, or from just one side. If they are sent from both sides, the period and retry parameters can be different at each side of the link. If you configure keepalives on only one side of the tunnel, the tunnel interface on the sending side might perceive the tunnel interface on the receiving side to be down because the sending interface is not receiving keepalives. From the receiving side of the tunnel, the link appears normal because no keepalives were enabled on the second side of the link.
Dropped Packets
Keepalive packets are treated as ordinary packets, so it is possible that they will be dropped. To reduce the chance that dropped keepalive packets will cause the tunnel interface to be taken down, increase the number of retries.
Note
delay the smaller keepalive packets long enough to cause the line protocol to go down. You may
need to experiment to determine the best values to use for the timeout and the number of
retry attempts.GRE Tunnels with IPSec
When using GRE with IPSec, the keepalives are encrypted like any other traffic. As with user data packets, if the IKE and IPSec security associations are not already active on the GRE tunnel, the first GRE keepalive packet will trigger IKE/IPSec initialization.
Examples
The following example shows how to set the keepalive interval to 3 seconds:
Router(config)# interface ethernet 0Router(config-if)# keepalive 3The following example shows how to set the keepalive interval to 3 seconds and the retry value to 7:
Router(config)# interface tunnel 1Router(config-if)# keepalive 3 7lbo
To set a cable length longer than 655 feet for a DS-1 link, use the lbo command in interface configuration mode on the interface for a T1 link. To delete the lbo value, use the no form of this command.
lbo {long {gain26 | gain36} {-15db | -22.5db | -7.5db | 0db} | short {133 | 266 | 399 | 533 | 655}}
no lbo
Syntax Description
Defaults
gain26 and 0db
Command Modes
Interface configuration
Command History
Usage Guidelines
This command is supported on T1 links only.
Each T1 port can operate in long-haul or short-haul mode. In long haul mode, the user must specify the gain and the line build out. In short-haul mode, the user must specify the cable length in feet.
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
On Cisco 7100 or Cisco 7200 series routers, the following example specifies a pulse gain of 36 decibels and a decibel pulse rate of -7.5 decibels:
Router(config)# interface atm 1/2Router(config-if)# lbo long gain36 -7.5dblinecode
To select the line-code type for T1 or E1 lines, use the linecode command in controller configuration mode.
linecode {ami | b8zs | hdb3}
Syntax Description
Defaults
AMI is the default for T1 lines.
High-density bipolar 3 is the default for E1 lines.Command Modes
Controller configuration
Command History
Usage Guidelines
Use this command in configurations in which the router or access server must communicate with T1 fractional data lines. The T1 service provider determines which line-code type, either ami or b8zs, is required for your T1 circuit. Likewise, the E1 service provider determines which line-code type, either ami or hdb3, is required for your E1 circuit.
This command does not have a no form.
Examples
The following example specifies B8ZS as the line-code type:
Router(config-controller)# linecode b8zsline-mode
To configure the controller to operate in two-wire or four-wire mode, or to configure automatic detection of the line mode, use the line-mode command in controller configuration mode. This command specifies the mode for the SHDSL port. To return to two-wire mode on line 0, use the no form of this command.
For CPE:
line-mode {2-wire line-number | 4-wire | auto}
no line-mode
For CO:
line-mode {2-wire line-number | 4-wire}
no line-mode
Syntax Description
Defaults
The default is two-wire mode if this command is omitted or if the 4-wire keyword is omitted. The default uses Line 0, which is the first pair of wires.
Command Modes
Controller configuration
Command History
Usage Guidelines
This command is used to configure the controller for two-wire and four-wire mode. To operate in four-wire mode for SHDSL, the line-mode command must be set to the 4-wire keyword.
Examples
4-Wire Line Mode Example
The following example configures the controller mode of DSL on the controller in slot 1 and port 0 to verify the controller status:
Router(config)# controller dsl 1/0Router(config-controller)# line-mode 4-wireCPE Line Mode Example
The following example configures the controller in slot 1 and port 0. The router is set to terminate as CPE with the line mode automatically selecting between two-wire mode and four-wire mode. The line rate has not been set to the value of 4608 before and displays the output from the router.
Router(config)# controller dsl 1/0Router(config-controller)# line-mode autoRouter(config-controller)# line-term cpeRouter(config-controller)# line-rate 4608Router(config-controller)#*Jun 15 17:39:49.680: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tn*Jun 15 17:39:51.680: %LINK-3-UPDOWN: Interface ATM1/0, changed state to down*Jun 15 17:39:52.680: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM1/0, cn*Jun 15 17:40:15.588: DSL 1/0 controller Link up! line rate: 4608 Kbps*Jun 15 17:40:15.588: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tp*Jun 15 17:40:27.504: %LINK-3-UPDOWN: Interface ATM1/0, changed state to up*Jun 15 17:40:28.504: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM1/0, cpRouter(config-controller)# exitRelated Commands
Specifies a line-rate for configuration and begins the line configuration mode.
Specifies a line-term for configuration and begins the line configuration mode.
line-rate
To specify a line rate for the DSL controller, use the line-rate command in controller configuration mode. To return the line rate to the default, use the no form of this command.
line-rate {auto | rate}
no line-rate
Syntax Description
Defaults
2-wire mode: line rate is set to auto
4-wire mode: line rate is set to 4608Command Modes
Controller configuration
Command History
Usage Guidelines
This command specifies the DSL line rate for the SHDSL port.
Line Condition
The line rate setting is based on the condition of the physical line. If the line condition is good, a higher rate can be used. When lesser quality exists on the line, use a slower rate.
If you set the line rate higher and the line condition is not good, the line will not drain. It might also flap or produce CRCs. Reduce the line rate so that the packet delivery is more consistent.
Line Rate in Two-Wire or Four-Wire Mode
Use this command to configure the line rate in two-wire or four-wire mode.
SHDSL Rate
The SHDSL rate is in kbps, but the line trains at the selected rate plus 16 kbps in 4-wire mode and 8 kbps in 2-wire mode of DSL framing overhead.
Note
•
•
Examples
CPE with Line Mode Automatically Selected
The following example displays the configuration of the controller in slot 1 and port 0. The router is set to terminate as CPE with the line mode automatically selecting between two-wire mode and four-wire mode. The line rate is set to 4608 kbps.
Router(config)# controller dsl 1/0Router(config-controller)# line-term cpeRouter(config-controller)# mode atmRouter(config-controller)# line-mode autoNo change in line modeRouter(config-controller)# line-rate ?384, 512, 640, 768, 896, 1024, 1152, 1280, 1408, 1536, 1664, 1792, 1920, 2048, 2176, 2304, 2432, 2560, 2688, 2816, 2944, 3072, 3200, 3328, 3456, 3584, 3712, 3840, 3968, 4096, 4224, 4352, 4480, and 4608Router(config-controller)# line-rate 4608Router(config-controller)#*Jun 15 17:39:49.680: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tn*Jun 15 17:39:51.680: %LINK-3-UPDOWN: Interface ATM1/0, changed state to down*Jun 15 17:39:52.680: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM1/0, cn*Jun 15 17:40:15.588: DSL 1/0 controller Link up! line rate: 4608 Kbps*Jun 15 17:40:15.588: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tp*Jun 15 17:40:27.504: %LINK-3-UPDOWN: Interface ATM1/0, changed state to up*Jun 15 17:40:28.504: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM1/0, cpRouter(config-controller)# exitFour-Wire Mode
The following example displays first the line-mode command, which is used to select the four-wire mode, followed by the line-rate command. The Cisco IOS help is used to display the available line rates. The rate of 4608 is selected, and the output of the router is shown.
Router(config)# controller dsl 1/0Router(config-controller)# line-mode 4-wireRouter(config-controller)#*Jun 15 18:00:48.159: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tn*Jun 15 18:00:50.159: %LINK-3-UPDOWN: Interface ATM1/0, changed state to down*Jun 15 18:00:51.159: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM1/0, cnRouter(config-controller)#Router(config-controller)# line-rate 4608Router(config-controller)#*Jun 15 18:01:36.627: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tn*Jun 15 18:01:36.967: %CONTROLLER-5-UPDOWN: Controller DSL 1/0, changed state tnRouter(config-controller)# exitRelated Commands
line-mode
Configures the controller to operate in two-wire or four-wire mode.
Specifies a line-term for configuration and begins the line configuration mode.
line-term
To specify a termination for the line, use the line-term command in controller configuration mode. To the default line termination value of cpe, use the no form of this command to return.
line-term {co | cpe}
no line-term
Syntax DescriptionC
Defaults
The default value is cpe.
Command Modes
Controller configuration
Command History
Usage Guidelines
This command is used to configure the line termination for use as either the central office (CO) or the customer premises equipment (CPE).
Examples
The following example displays the configuration of the controller in slot 1 and port 0. The router is set to terminate as CPE with the line mode automatically selecting between two-wire mode and four-wire mode.
Router(config)# controller dsl 1/0Router(config-controller)# line-term cpeRouter(config-controller)# mode atmRouter(config-controller)# line-mode autoNo change in line modeRelated Commands
line-mode
Configures the controller to operate in two-wire or four-wire mode.
line-rate
Specifies a line rate for configuration and begins the line configuration mode.
line-termination
To set the line termination on an E1 controller, use the line-termination command in controller configuration mode. To return to the default line termination, use the no form of this command.
line-termination {75-ohm | 120-ohm}
no line-termination
Syntax Description
75-ohm
Specifies 75-ohm unbalanced termination.
120-ohm
Specifies 120-ohm balanced termination. This is the default.
Defaults
120-ohms
Command Modes
Controller configuration
Command History
Usage Guidelines
This command applies only to E1 controllers. To determine the line termination setting for the controller, use the show controllers e1 command.
Examples
In the following example, the line termination is set to 75 ohms for the E1 port located in shelf 6, slot 0, port 0:
Router# configure terminalRouter(config)# controller e1 6/0/0Router(config-controller)# line-termination 75-ohmRouter(config-controller)# endRelated Commands
show controllers e1
Displays information about the E1 links supported by the NPM (Cisco 4000) or MIP (Cisco 7500 series).
link-test
To reenable the link-test function on a port on an Ethernet hub of a Cisco 2505 or Cisco 2507 router, use the link-test command in hub configuration mode. To disable this function, use the no form of this command.
link-test
no link-test
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Hub configuration
Command History
Usage Guidelines
This command applies to a port on an Ethernet hub only. Disable this feature if a 10Base-T twisted-pair device at the other end of the hub does not implement the link test function.
Examples
The following example disables the link test function on hub 0, ports 1 through 3:
Router(config)# hub ethernet 0 1 3Router(config-hub)# no link-testRelated Commands
hub
Enables and configures a port on an Ethernet hub of a Cisco 2505 or Cisco 2507 router.
local ip address
To define an IP address to identify a local circuit emulation (CEM) channel, use the local ip address command in CEM xconnect configuration mode.
local ip address ip-address
Syntax Description
Defaults
The default local IP address is 0.0.0.0.
Command Modes
CEM xconnect configuration
Command History
Usage Guidelines
The local IP address used to identify the local end of a CEM connection must be the same as the IP address defined by the remote-ip-address argument used in the xconnect command to identify the CEM channel at the other end of the CEM connection.
Note
local IP address provided that each local IP address defines a unique UDP port number using the
local udp port command.Examples
The following example demonstrates how to configure the IP address of the local endpoint of the CEM over IP (CEoIP) connection.
Router(config-cem-xconnect)# local ip address 10.0.5.1
Related Commands
local udp port
To define the User Datagram Protocol (UDP) port of the local endpoint of a circuit emulation (CEM) connection, use the local udp port command in CEM xconnect configuration mode.
local udp port port
Syntax Description
port
Number of the CEM local UDP port. Possible values are 0, 2141, and 15872 through 16383. The default is 0.
Defaults
The default local UDP port number is 0.
Command Modes
CEM xconnect configuration
Command History
Usage Guidelines
This command does not have a no form. To remove a local UPD port number either configure a new UPD port number or enter the no xconnect command to disable the connection and all its parameters.
Examples
The following example demonstrates how to configure the UDP port of the local endpoint of the CEM over IP (CEMoIP) connection.
Router(config-cem-xconnect)# local udp port 2141
Related Commands
local-lnm
To enable Lanoptics Hub Networking Management of a PCbus Token Ring interface, use the local-lnm command in interface configuration mode. To disable Lanoptics Hub Networking Management, use the no form of this command.
local-lnm
no local-lnm
Syntax Description
This command has no arguments or keywords.
Defaults
Management is not enabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
The Token Ring interface on the AccessPro PC card can be managed by a remote LAN manager over the PCbus interface. At present, the Lanoptics Hub Networking Management software running on an IBM compatible PC is supported.
Examples
The following example enables Lanoptics Hub Networking Management:
Router(config-if)# local-lnmlogging event
To enable notification of interface, subinterface, and Frame Relay data link connection identifier (DLCI) data link status changes, use the logging event command in interface configuration mode. To disable notification, use the no form of this command.
logging event {dlci-status-change | link-status | subif-link-status [ignore-bulk]}
no logging event {dlci-status-change | link-status | subif-link-status [ignore-bulk]}
Syntax Description
Defaults
For system images, notification of interface, subinterface, and Frame Relay DLCI data link status changes is enabled by default.
For boot images, notification of Frame Relay subinterface and DLCI data link status changes is disabled by default. Notification of interface data link status changes is enabled by default.
Command Modes
Interface configuration
Command History
Examples
The following example shows how to enable notification of subinterface link status changes:
Router(config-if)# logging event subif-link-statusThe following are examples of Frame Relay DLCI and subinterface status change notification messages filtered by the logging event command:
00:16:22: %FR-5-DLCICHANGE: Inteface Serial3/0/0:1 - DLCI 105 state changed to INACTIVE00:16:22: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial3/0/0:1.5, changed state to downlogging-events
to print typical T3 controller Up and Down messages on a Channelized T3 Port Adapter, use the logging-events command in T3 controller configuration mode. Use the no form of this command to disable printing of the T3 controller Up and Down messages.
logging-events [detail]
[no] logging-events
Syntax Description
detail
(Optional) Enables printing the reason code when a T3 controller changes from the Up to Down state.
Defaults
The logging-events command is the default.
Command Modes
T3 controller configuration
Command History
Usage Guidelines
When the no logging-events command disables printing of the T3 controller Up and Down messages, these messages will neither appear on the console nor in the logs.
Examples
The following example uses the logging-events [detail] command to show the Out-of-Frame (OOF) reason code when the T3 controller changes from an Up state to a Down state:
Router(config-controller)# logging-events detail*Jun 19 17:47:50: %CONTROLLER-5-DOWNDETAIL: Controller T3 4/1, changed state to down due to OOFRelated Commands
t1 logging-events
Prints the typical T1 controller Up and Down messages on a channelized T3 port adapter.
loopback (CEM)
To set the loopback method for testing a T1, E1, or serial CEM interface, use the loopback command in controller configuration or CEM configuration mode. To remove any existing loopback, use the no form of this command.
Cisco NM-CEM-4SER
loopback {local | network}
no loopback
Cisco NM-CEM-4TE1
loopback {local {payload | line} | network}
no loopback
Syntax Description
Defaults
No loopback is configured.
Command Modes
Cisco NM-CEM-4SER
CEM configuration
Cisco NM-CEM-4TE1
Controller configuration
Command History
Usage Guidelines
Use this command to create a loopback for a CEM interface. You can use a loopback to test for equipment malfunction caused by the interface.
The NM-CEM-4TE1 does not respond to loopback requests initiated by the CPE, locally attached or remote, using the extended super frame (ESF) Facility Data Link (FDL) mechanism or by any other mechanism.
The NM-CEM-4SER does not respond to any form of loopback request initiated by the locally attached or remote CPE on the Local Loop (LL) or Remote Loop (RL) control leads. Nor does the NM-CEM-4SER respond to any form of loopback request initiated by the locally attached or remote CPE using in-band loopback codes.
Examples
The following example shows how to create a loopback on a CEM T1/E1 interface so that data received from a remote CPE is transmitted back to the remote CPE on the network.
Router(config-controller)# loopback networkThe following example shows how to create a loopback of data in individual time slots on a CEM T1/E1 interface. Data received from a locally attached CPE will be sent back to the locally attached CPE.
Router(config-controller)# loopback local payloadThe following example shows how to create a loopback on a serial CEM channel so that data received from a remote CPE is transmitted back to the remote CPE on the network.
Router(config-cem)# loopback networkRelated Commands
cem
Enters circuit emulation configuration mode.
controller
Enters controller configuration mode.
loopback (DSL controller)
To test the controller and configure the core loopback, use the loopback (DSL Controller) command in controller configuration mode. To remove the loopback interface, use the no form of this command.
loopback {analog | digital}
no loopback
Syntax Description
analog
Loops the circuit at the analog hybrid to verify the analog loopback hardware to the analog hybrid.
digital
Loops the circuit at the framer to verify the hardware to the framer.
Defaults
No default behavior or values.
Command Modes
Controller configuration
Command History
Usage Guidelines
Analog and digital loopbacks are local loopbacks. Digital loopbacks loop the circuit at the framer to verify the hardware to the framer, and analog loopbacks loop the circuit at the analog hybrid to verify the analog loopback hardware to the analog hybrid. The controller must be shut down before loopback can be configured.
Examples
If the controller is still up, the router will prompt you to turn the controller off as shown in this example:
Router(config-controller)# loopback analogPlease shut down the xDSL controllerRouter(config-controller)# loopback digitalPlease shut down the xDSL controllerThe following example shows the configuration of a loopback digital interface:
Router(config-controller)# loopback digitalPlease shut down the xDSL controllerRouter(config-controller)# shutdownRouter(config-controller)#00:59:50: %CONTROLLER-5-UPDOWN: Controller DSL 0/0, changed state toadministratively downRouter(config-controller)#Router(config-controller)# loopback digitalRouter(config-controller)# no shutdownApr 23 06:59:01.435: DSL 0/0 controller Link up! line rate: 4608 Kbpso00:59:59: %CONTROLLER-5-UPDOWN: Controller DSL 0/0, changed state to upRouter(config-controller)#endRouter# show controllers dsl 0/0DSL 0/0 controller UPLocal Digital loopback is runningGlobespan xDSL controller chipsetDSL mode: SHDSL Annex BFrame mode: UtopiaConfigured Line rate: 4608KbpsLine Re-activated 4 times after system bootupLOSW Defect alarm: ACTIVECRC per second alarm: ACTIVELine termination: COFPGA Revision: 0xA7Line 0 statisticsCurrent 15 min CRC: 679Current 15 min LOSW Defect: 8Current 15 min ES: 5Current 15 min SES: 5Current 15 min UAS: 397Previous 15 min CRC: 0Previous 15 min LOSW Defect: 0Previous 15 min ES: 0Previous 15 min SES: 0Previous 15 min UAS: 0Line 1 statisticsCurrent 15 min CRC: 577Current 15 min LOSW Defect: 8Current 15 min ES: 7Current 15 min SES: 4Current 15 min UAS: 411Previous 15 min CRC: 0Previous 15 min LOSW Defect: 0Previous 15 min ES: 0Previous 15 min SES: 0Previous 15 min UAS: 0Line-0 statusChipset Version: 1Firmware Version: A29733Modem Status: un checked mode, Status 83Last Fail Mode: No Failure status:0x0Line rate: 2312 KbpsFramer Sync Status: In SyncRcv Clock Status: In the RangeLoop Attenuation: 0.0 dBTransmit Power: 13.5 dBReceiver Gain: 936.8420 dBSNR Sampling: 16.960 dBLine-1 statusChipset Version: 1Firmware Version: A29733Modem Status: un checked mode, Status 83Last Fail Mode: No Failure status:0x0Line rate: 2312 KbpsFramer Sync Status: In SyncRcv Clock Status: In the RangeLoop Attenuation: 0.0 dBTransmit Power: 13.5 dBReceiver Gain: 936.8420 dBSNR Sampling: 16.3590 dBDying Gasp: PresentRelated Commands
loopback (E3 controller)
To loop an entire E3 line toward the line and back toward the router, use the loopback command in controller configuration mode. To remove the loop, use the no form of this command.
loopback {local | network {line | payload}}
no loopback
Syntax Description
Defaults
local
Command Modes
Controller configuration
Command History
Usage Guidelines
Use this command for troubleshooting purposes. To verify that a loopback is configured on the interface, use the show controllers e3 EXEC command. Note that line loopback is available only in C-bit parity mode.
Examples
The following example shows how to configure the controller located in slot 1, port 0 for a local loopback:
Router(config)# controller e3 1/0Router(config-controller)# loopback localRelated Commands
loopback (interface)
To diagnose equipment malfunctions between the interface and device, use the loopback command in interface configuration mode. To disable the test, use the no form of this command.
loopback
no loopback
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Loopback on HSSI Cards
On High-Speed Serial Interface (HSSI) cards, the loopback function configures a two-way internal and external loop on the HSA applique of the specific interface.
Loopback on MCI and SCI Serial Interface Cards
On MCI and SCI serial interface cards, the loopback functions when a CSU/DSU or equivalent device is attached to the router or access server. The loopback command loops the packets through the CSU/DSU to configure a CSU loop, when the device supports this feature.
Loopback on MCI and MEC Ethernet Cards
On the MCI and MEC Ethernet cards, the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
Loopback on CSC-FCI FDDI Cards
On the CSC-FCI FDDI card, the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
Loopback on Token Ring Interface Cards
On all Token Ring interface cards (except the 4-megabit CSC-R card), the interface receives back every packet it sends when the loopback command is enabled. Loopback operation has the additional effect of disconnecting network server functionality from the network.
Active Loopback Interfaces
To show interfaces currently in loopback operation, use the show interfaces loopback EXEC command.
Note
Examples
The following example configures the loopback test on Ethernet interface 4:
Router(config)# interface ethernet 4Router(config-if)# loopbackRelated Commands
down-when-looped
Configures an interface to inform the system it is down when loopback is detected.
show interfaces loopback
Displays information about the loopback interface.
loopback (J1 controller )
To set the loopback method for testing the J1 interface, use the loopback command in controller configuration mode. To turn off loopback, use the no form of this command. This command should be used for testing purposes only.
loopback {local | line | isolation}
no loopback {local | line | isolation}
Syntax Description
local
Places the interface into local loopback mode.
line
Places the interface into external loopback mode at the line level.
isolation
Places the interface into both local and line loopback mode.
Defaults
No loopback is configured.
Command Modes
Controller configuration
Command History
Examples
The following example establishes a loopback of the incoming J1 signal on controller J1 3/0:
Router(config)# controller j1 3/0Router(config-controller)# loopback lineloopback (PA-MC-8TE1+ port adapter)
To enable loopback testing of data for the PA-MC-8TE1+ port adapter, use the loopback command in interface configuration mode. To disable loopback testing, use the no form of this command.
loopback [internal | line]
no loopback [internal | line]
Syntax Description
Defaults
Loopback mode is not enabled.
Command Modes
Interface configuration
Command History
Examples
In the following example, a loopback is set for the PA-MC-8TE1+ port adapter in slot 2:
Router(config)# interface 2/0Router(config-if)# loopback lineloopback (T1 interface)
To loop individual T1 channels on the CT3IP in Cisco 7000 series routers that have the RSP7000 and RSP7000CI and in Cisco 7500 series routers, use the loopback command in interface configuration mode. To remove the loopback, use the no form of this command.
loopback [local | network {line | payload} | remote {line {fdl {ansi | bellcore} | inband} | payload [fdl] [ansi]}]
no loopback
Syntax Description
Defaults
No loopback is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command for troubleshooting purposes.
To better diagnose T1 provisioning problems, you can place the remote CSU or remote SmartJack into loopback. The loopback remote line fdl interface configuration command allows you to place either the CSU or the SmartJack into loopback:
•
•
When both are configured, transmission of loss of frame (LOF) indication (yellow alarm) takes priority over transmission of some facilities data link (FDL) messages.
If the remote loopback appears not to be working, use the show controllers t3 command to determine if the given T1 is currently attempting to transmit a LOF indication (yellow alarm):
Router# show controllers t3 0/0/0:2T3 0/0/0 is up.CT3 H/W Version: 5, CT3 ROM Version: 1.2, CT3 F/W Version: 2.5.9Mx H/W version: 2, Mx ucode ver: 1.34T1 2 is down, speed: 1536 kbs, non-inverted datatimeslots: 1-24FDL per AT&T 54016 spec.Transmitter is sending LOF Indication.Receiver is getting AIS.If the transmitter is sending a LOF indication, as in the previous example, stop the transmission of the LOF indication (yellow alarm) with the no t1 yellow generation configuration command as shown in the following example:
Router(config)# controllers t3 0/0/0Router(config-controller)# no t1 2 yellow generationRouter(config-controller)# Ctrl-DTo verify that the transmission of the LOF indication (yellow alarm) has stopped, use the show controllers t3 command:
Router# show controllers t3 0/0/0:2T3 0/0/0 is up.CT3 H/W Version: 5, CT3 ROM Version: 1.2, CT3 F/W Version: 2.5.9Mx H/W version: 2, Mx ucode ver: 1.34T1 2 is down, speed: 1536 kbs, non-inverted datatimeslots: 1-24FDL per AT&T 54016 spec.Receiver is getting AIS.Framing is ESF, Line Code is B8ZS, Clock Source is Internal.Yellow Alarm Generation is disabledThen retry the remote loopback command. When diagnosis is complete, remember to reenable the LOF indication (yellow alarm).
You can also loopback all the T1 channels by using the loopback (CT3IP) interface configuration command.
Examples
The following example configures T1 channel 5 for a local loopback:
Router(config)# interface serial 3/0/0:5Router(config-if)# loopback localRelated Commands
loopback (T3 controller)
To loop the entire T3 (all 28 T1 channels) line on the T3 controller or on the CT3IP in Cisco 7500 series routers, use the loopback command in controller configuration mode. To remove the loop, use the no form of this command.
loopback {local | network {line | payload} | remote}
no loopback
Syntax Description
Defaults
No loops are configured on the T3 line.
Command Modes
Controller configuration
Command History
Usage Guidelines
Use this command for troubleshooting purposes. To verify that a loopback is configured on the interface, use the show controllers T3 EXEC command. Note that remote loopback is available only in C-bit parity mode.
You can also loopback each T1 channel by using the loopback interface configuration command for T1.
For more information, refer to the "Troubleshooting the T3 and T1 Channels" section in the "Configuring Serial Interfaces" chapter of the Cisco IOS Interface and Hardware Component Configuration Guide.
Examples
The following example configures the T3 or CT3IP for a local loopback:
Router(config)# controller t3 3/0/0Router(config-controller)# loopback localRelated Commands
loopback (T3/E3 interface)
To loop the serial interface on a PA-T3 or PA-E3 port adapter, use the loopback command in interface configuration mode. To remove the loopback, use the no form of this command.
PA-T3 Port Adapter
loopback {dte | local | network {line | payload} | remote}
no loopback
PA-E3 Port Adapter
loopback {dte | local | network {line | payload}}
no loopback
Syntax Description
Defaults
No loops are configured on the serial interface.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command for troubleshooting purposes.
To verify that a loopback is configured on the interface, use the show interfaces serial or show interfaces loopback command.
Examples
The following example configures the serial interface located in slot 3/0/0 for a local loopback:
Router(config)# interface serial 3/0/0Router(config-if)# loopback localRelated Commands
loopback applique
To configure an internal loop on the High-Speed Serial Interface (HSSI) applique, use the loopback applique command in interface configuration mode. To remove the loop, use the no form of this command.
loopback applique
no loopback applique
Syntax Description
This command has no arguments or keywords.
Defaults
No loops are configured on the HSSI applique.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command loops the packets within the applique to provide a way to test communication within the router or access server. It is useful for sending pings to yourself to check functionality of the applique.
To show a specific interface that is currently in loopback operation, use the show interfaces loopback EXEC command.
Examples
The following example configures the loopback test on the HSSI applique:
Router(config)# interface serial 1Router(config-if)# loopback appliqueRelated Commands
loopback dte
To loop packets back to the DTE from the CSU/DSU, when the device supports this function, use the loopback dte command in interface configuration mode. To remove the loop, use the no form of this command.
loopback dte
no loopback dte
Syntax Description
This command has no arguments or keywords.
Defaults
No loops are configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command is useful for testing the DTE-to-DCE cable.
This command is used to test the performance of the integrated CSU/DSU. Packets are looped from within the CSU/DSU back to the serial interface of the router. Send a test ping to see if the packets successfully looped back. To cancel the loopback test, use the no loopback dte command.
When using the 4-wire 56/64-kbps CSU/DSU module, an out-of-service signal is transmitted to the remote CSU/DSU.
To show a specific interface that is currently in loopback operation, use the show interfaces loopback EXEC command.
Examples
The following example configures the loopback test on the DTE interface:
Router(config)# interface serial 0Router(config-if)# loopback dteRelated Commands
loopback line
To loop packets completely through the CSU/DSU to configure the CSU loop, use the loopback line command in interface configuration mode. To remove the loop, use the no form of this command.
loopback line [payload]
no loopback line [payload]
Syntax Description
payload
(Optional) Configures a loopback point at the DSU and loops data back to the network on an integrated CSU/DSU.
Defaults
No loops are configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command is useful for testing the DCE device (CSU/DSU) itself. When the loopback line command is configured on the 2-wire 56-kbps CSU/DSU module or the 4-wire 56/64-kbps CSU/DSU modules, the network data loops back at the CSU and the router data loops back at the DSU. If the CSU/DSU is configured for switched mode, you must have an established connection to perform a payload-line loopback. To loop the received data through the minimum amount of CSU/DSU circuitry, issue the loopback line command.
When you issue the loopback line payload command on an integrated CSU/DSU module, the router cannot transmit data through the serial interface for the duration of the loopback. Choosing the DSU as a loopback point loops the received-network data through the maximum amount of CSU/DSU circuitry. Data is not looped back to the serial interface. An active connection is required when operating in switched mode for payload loopbacks.
If you enable the loopback line command on the fractional T1/T1 module, the CSU/DSU performs a full-bandwidth loopback through the CSU portion of the module and data transmission through the serial interface is interrupted for the duration of the loopback. No reframing or corrections of bipolar violation errors or cyclic redundancy check (CRC) errors are performed. When you configure the loopback line payload command on the FT1/T1 module, the CSU/DSU performs a loopback through the DSU portion of the module. The loopback line payload command reframes the data link, regenerates the signal, and corrects bipolar violations and Extended Super Frame CRC errors.
When performing a T1-line loopback with Extended Super Frame, communication over the facilities data link is interrupted, but performance statistics are still updated. To show interfaces currently in loopback operation, use the show service-module EXEC command.
To show interfaces that are currently in loopback operation on other routers, use the show interfaces loopback EXEC command.
Examples
The following example configures the loopback test on the DCE device:
Router(config)# interface serial 1Router(config-if)# loopback lineThe following example shows how to configure a payload loopback on a Cisco 2524 or Cisco 2525 router:
Router1(config-if)# loopback line payloadLoopback in progressRouter1(config-if)# no loopback lineThe following example shows the output on a Cisco 2524 or Cisco 2525 router when you loop a packet in switched mode without an active connection:
Router1(config-if)# service-module 56k network-type switchedRouter1(config-if)# loopback line payloadNeed active connection for this type of loopback% Service module configuration command failed: WRONG FORMAT.Related Commands
show interfaces loopback
Displays information about the loopback interface.
show service-module
Displays the performance report for an integrated CSU/DSU.
loopback remote (interface)
To loop packets through a CSU/DSU, over a DS3 link or a channelized T1 link, to the remote CSU/DSU and back, use the loopback remote command in interface configuration mode. To remove the loopback, use the no form of this command.
FT1/T1 CSU/DSU Modules
loopback remote {full | payload | smart-jack} [0in1 | 1in1 | 1in2 | 1in5 | 1in8 | 3in24 | qrw | user-pattern 24-bit-binary-value]
no loopback remote {full | payload | smart-jack}
2- and 4-Wire, 56/64-kbps CSU/DSU Modules
loopback remote [2047 | 511 | stress-pattern pattern-number]
no loopback remote
Syntax Description
Defaults
No remote loopback interface is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command is used for testing the data communication channels along with or without remote CSU/DSU circuitry. The loopback is usually performed at the line port, rather than the DTE port, of the remote CSU/DSU.
For a multiport interface processor connected to a network via a channelized T1 link, the loopback remote interface configuration command applies if the remote interface is served by a DDS line (56 kbps or 64 kbps) and if the device at the remote end is a CSU/DSU. In addition, the CSU/DSU at the remote end must react to latched DDS CSU loopback codes. Destinations that are served by other types of lines or that have CSU/DSUs that do not react to latched DDS CSU codes cannot participate in an interface remote loopback. Latched DDS CSU loopback code requirements are described in AT&T specification TR-TSY-000476, "OTGR Network Maintenance Access and Testing."
For the integrated FT1/T1 CSU/DSU module, the loopback remote full command sends the loopup code to the remote CSU/DSU. The remote CSU/DSU performs a full-bandwidth loopback through the CSU portion of the module. The loopback remote payload command sends the loopup code on the configured time slots, while maintaining the D4-extended super frame. The remote CSU/DSU performs the equivalent of a loopback line payload request. The remote CSU/DSU loops back only those time slots that are configured on the remote end. This loopback reframes the data link, regenerates the signal, and corrects bipolar violations and extended super frame CRC errors. The loopback remote smart-jack command sends a loopup code to the remote smart jack. You cannot put the local smart jack into loopback.
Failure to loopup or initiate a remote loopback request could be caused by enabling the no service-module t1 remote-loopback command or having an alternate remote-loopback code configured on the remote end. When the loopback is terminated, the result of the pattern test is displayed.
For the 2- and 4-wire, 56/64-kbps CSU/DSU module, an active connection is required before a loopup can be initiated while in switched mode. When transmitting V.54 loopbacks, the loopback mode is initiated on the remote device using V.54 messages. Failure to loopup or initiate a remote loopback request could be caused by enabling the no service-module 56k remote-loopback command.
To display interfaces that are currently in loopback operation, use the show interfaces loopback EXEC command.
Examples
Example for Remote Loopback Test
The following example configures a remote loopback test:
Router(config)# interface serial 0 Router(config-if)# loopback remoteExample of Full-Bandwidth Line Loopback
The following example configures the remote device into full-bandwidth line loopback while specifying the qrw test pattern over the T1 CSU/DSU module on a Cisco 2524 or Cisco 2525 router:
Router(config)# interface serial 0Router(config-if)# loopback remote full qrwRouter(config-if)#%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0, changed state to down%LINK-3-UPDOWN: Interface Serial0, changed state to down%SERVICE_MODULE-5-LOOPUPREMOTE: Unit 0 - Remote unit placed in loopbackExample of Loopback Stress Pattern
The following example transmits a remote loopback stress pattern over the 4-wire, 56/64-kbps CSU/DSU module, which tests the stress clocking of the network:
Router(config-if)# loopback remote stress-pattern 1Router(config-if)#%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1, changed state to down%LINK-3-UPDOWN: Interface Serial1, changed state to down%SERVICE_MODULE-5-LOOPUPREMOTE: Unit 1 - Remote unit placed in loopbackRelated Commands
