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Cisco IOS Interface Command Reference, Release 12.2
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About the Cisco IOS Software Documentation
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Using Cisco IOS Software
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Interface Commands - Introduction
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Interface Commands (aps-authenticate - cut-through)
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Interface Commands (dce-terminal-timing enable - interface)
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Interface Commands (interface fastethernet - loopback line)
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Interface Commands (loopback remote - service module t1 remote-loopback)
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Interface Commands (service-module t1 timeslots - show hub)
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Interface Commands (show interfaces - show interfaces vg-anylan)
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Interface Commands (show pas caim - tx-queue-limit)
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Dial Shelf Management Commands
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Online index for Cisco IOS Interface Comand Reference
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Feedback
Table Of Contents
service-module 56k clock source
service-module 56k data-coding
service-module 56k network-type
service-module 56k remote-loopback
service-module 56k switched-carrier
service-module t1 clock source
service-module t1 remote-alarm-enable
service-module t1 remote-loopback
loopback remote (interface)
To loop packets through a CSU/DSU, over a DS-3 link or a channelized T1 link, to the remote CSU/DSU and back, use the loopback remote 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 24bit-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
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
This command applies only when the remote CSU/DSU device is configured for this function. It 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 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 Superframe. 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 remote device is commanded into loopback using V.54 messages. Failure to loopup or initiate a remote loopback request could be caused by enabling the no service-module 56k remote-loopback command.
To show interfaces that are currently in loopback operation, use the show interfaces loopback command in EXEC mode.
Examples
The following example configures a remote loopback test:
Router(config)# interface serial 0 Router(config-if)# loopback remoteThe 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 loopbackThe 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
mdl
To configure the Maintenance Data Link (MDL) message defined in the ANSI T1.107a-1990 specification for the CT3 in a Cisco AS5800 universal access server, or for the CT3IP in Cisco 7500 series routers, use the mdl command in interface configuration mode. To remove the message, use the no form of this command.
mdl {transmit {path | idle-signal | test-signal} | string {eic | lic | fic | unit | pfi | port | generator} string}
no mdl {transmit {path | idle-signal | test-signal} | string {eic | lic | fic | unit | pfi | port | generator} string}
Syntax Description
Defaults
No MDL message is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
Use the show controllers t3 command to display MDL information (received strings). MDL information is displayed only when framing is set to C-bit.
Note
MDL is supported only when the DS3 framing is C-bit parity.
Examples
The following examples show several of the mdl commands for the CT3IP in slot 9:
Router(config)# controller t3 9/0/0Router(config-controller)# mdl string eic Router ARouter(config-controller)# mdl string lic Test NetworkRouter(config-controller)# mdl string fic Building BRouter(config-controller)# mdl string unit ABCRelated Commands
media-type
To specify the physical connection on an interface, use the media-type command in interface configuration mode. To restore the default value, use the no form of this command.
media-type {aui | 10baset | 100baset | mii}
no media-type {aui | 10baset | 100baset | mii}
Syntax Description
Defaults
An AUI 15-pin physical connection is the default setting on Cisco 4000 series routers.
100BASE-T physical connection is the default setting on Cisco 7000 series and Cisco 7200 series routers.
Command Modes
Interface configuration
Command History
Usage Guidelines
To specify the physical connection on an interface, use the following interface configuration:
•
•
•
Examples
The following example selects an RJ-45 10BASE-T physical connection on Ethernet interface 1:
Router(config)# interface ethernet 1Router(config-if)# media-type 10basetThe following example specifies a media-independent interface physical connection to Fast Ethernet slot 0, port 1 on the Cisco 7000 or 7200 series:
Router(config)# interface fastethernet 0/1Router(config-if)# media-type miiThe following example specifies a media-independent interface physical connection to Fast Ethernet slot 0, port adapter 1, port 1 on the Cisco 7500 series:
Router(config)# interface fastethernet 0/1/1Router(config-if)# media-type miimedia-type half-duplex
The media-type half-duplex command is replaced by the half-duplex command. See the description of the half-duplex command in this chapter for more information.
modem dtr-delay
To control the time that a data terminal ready (DTR) signal is held down when a line clears, use the modem dtr-delay command in line configuration mode. To restore the default hold down time, use the no form of this command.
modem dtr-delay seconds
no modem dtr-delay seconds
Syntax Description
Defaults
The default DTR signal hold down time is 5 seconds.
Command Modes
Line configuration
Command History
Usage Guidelines
Use this command to reduce the time that a DTR signal is held down after an asynchronous line clears and before the DTR signal is raised again to accept new calls. Incoming calls may be rejected in heavily loaded systems even when modems are unused because the default DTR hold down interval may be too long. The modem dtr-delay command is designed for lines used for an unframed asynchronous session such as Telnet. Lines used for a framed asynchronous session such as PPP should use the pulse-time interface command.
Examples
The following example shows how to specify a DTR hold down interval of 2 seconds:
Router(config)# line 7Router(config-line)# modem dtr-delay 2Related Commands
mop enabled
To enable an interface to support the Maintenance Operation Protocol (MOP), use the mop enabled command in interface configuration mode. To disable MOP on an interface, use the no form of this command.
mop enabled
no mop enabled
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled on Ethernet interfaces and disabled on all other interfaces.
Command Modes
Interface configuration
Command History
Examples
The following example enables MOP for serial interface 0:
Router(config)# interface serial 0Router(config-if)# mop enableRelated Commands
mop sysid
To enable an interface to send out periodic Maintenance Operation Protocol (MOP) system identification messages, use the mop sysid command in interface configuration mode. To disable MOP message support on an interface, use the no form of this command.
mop sysid
no mop sysid
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Interface configuration
Command History
Usage Guidelines
You can still run MOP without having the background system ID messages sent. This command lets you use the MOP remote console, but does not generate messages used by the configurator.
Examples
The following example enables serial interface 0 to send MOP system identification messages:
Router(config)# interface serial 0Router(config-if)# mop sysidRelated Commands
mop device-code
Identifies the type of device sending MOP sysid messages and request program messages.
Enables an interface to support the MOP.
mtu
To adjust the maximum packet size or maximum transmission unit (MTU) size, use the mtu command in interface configuration mode. To restore the MTU value to its original default value, use the no form of this command.
mtu bytes
no mtu
Syntax Description
Defaults
Table 13 lists default MTU values according to media type.
Table 13 Default Media MTU Values
Ethernet
1500
Serial
1500
Token Ring
4464
ATM
4470
FDDI
4470
HSSI (HSA)
4470
Command Modes
Interface configuration
Command History
Usage Guidelines
Each interface has a default maximum packet size or MTU size. This number generally defaults to the largest size possible for that interface type. On serial interfaces, the MTU size varies, but cannot be set smaller than 64 bytes.
Caution
%RSP-3-Restart:cbus complex.
Protocol-Specific Versions of mtu Command
Changing the MTU value with the mtu interface configuration command can affect values for the protocol-specific versions of the command (the ip mtu command, for example). If the value specified with the ip mtu interface configuration command is the same as the value specified with the mtu interface configuration command, and you change the value for the mtu interface configuration command, the ip mtu value automatically matches the new mtu interface configuration command value. However, changing the values for the ip mtu configuration commands has no effect on the value for the mtu interface configuration command.
ATM and LANE Interfaces
ATM interfaces are not bound by what is configured on the major interface. By default, MTU on a subinterface is equal to the default MTU (4490); if a client is configured the default is 1500. MTU can be changed on subinterfaces, but it may result in recarving of buffers to accommodate the new maximum MTU on the interface.
Examples
The following example specifies an MTU of 1000 bytes:
Router(config)# interface serial 1Router(config-if)# mtu 1000Related Commands
encapsulation smds
Enables SMDS service on the desired interface.
ip mtu
Sets the MTU size of IP packets sent on an interface.
national bit
To set the E3 national bit in the G.751 frame used by the PA-E3 port adapter, use the national bit command in interface configuration mode. To return to the default E3 national bit, use the no form of this command.
national bit {0 | 1}
no national bit
Syntax Description
Defaults
0 national bit
Command Modes
Interface configuration
Command History
Usage Guidelines
The national bit command sets bit 12 in the E3 frame.
To verify the national bit configured on the interface, use the show controllers serial EXEC command.
Examples
The following example sets the national bit to 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)# national bit 1Related Commands
Sets the E3 international bit in the G.751 frame used by the PA-E3 port adapter.
Displays information that is specific to the interface hardware.
national reserve
To set the E1 national bit, enter the national reserve command in interface configuration mode. To return to the default E1 national bit, use the no form of this command.
national reserve <0-1><0-1><0-1><0-1><0-1><0-1>
no national reserve
Syntax Description
This command has no arguments or keywords.
Defaults
111111
Command Modes
Interface configuration
Command History
12.0(5)XE
This command was introduced.
12.0(7)XE1
Support for Cisco 7100 series routers was added.
12.1(5)T
This command was integrated into Cisco IOS Release 12.1(5)T.
Usage Guidelines
This command applies only for E1. This command not only sets the national reserve bits but also sets the international bit as well. The far left digit represents the international bit. All six digits must be present for the pattern to be valid.
Examples
On Cisco 7100 series routers, the following example sets the national bit on interface 1 on the port adapter in slot 0 to no scrambling:
interface atm1/0national reserve 011011negotiation
To configure speed, duplex, and flow control on the Gigabit Ethernet port of the Cisco 7200-I/O-GE+E, use the negotiation command in interface configuration mode. To disable automatic negotiation, use the no negotiation auto command .
negotiation {forced | auto}
no negotiation auto
Syntax Description
Defaults
Negotiation auto
Command Modes
Interface configuration
Command History
Usage Guidelines
The negotiation command is applicable only to the Gigabit Ethernet interface of the Cisco 7200-I/O-GE+E. The negotiation auto command is used instead of the duplex and speed commands (which are used on Ethernet and Fast Ethernet interfaces) to automatically configure the duplex and speed settings of the interfaces. The negotiation forced command is used to configure the Gigabit Ethernet interface to be 1000/full-duplex only and to disable flow control. The Gigabit Ethernet interface of the Cisco 7200-I/O-GE+E is restricted to 1000 Mbps/full duplex only. Autonegotiation negotiates only to these values.
Examples
The following example configures the Gigabit Ethernet interface of the Cisco 7200-I/O-GE +E to autonegotiate:
configure terminalinterface gigabitethernet 0/0negotiation autoRelated Commands
Checks the status and configuration settings of the Gigabit Ethernet interface of the Cisco 7200-I/O-GE+E.
nrzi-encoding
To enable nonreturn-to-zero inverted (NRZI) line-coding format, use the nrzi-encoding command in interface configuration mode. To disable this capability, use the no form of this command.
nrzi-encoding [mark]
no nrzi-encoding
Syntax Description
Defaults
Disabled
Command Modes
Interface configuration
Command History
10.0
This command was introduced.
11.3
The mark keyword was added for the Cisco 7200 series routers and Cisco 7500 series routers.
Usage Guidelines
All FSIP, PA-8T, and PA-4T+ interface types support nonreturn-to-zero (NRZ) and NRZI format. This is a line-coding format that is required for serial connections in some environments. NRZ encoding is most common. NRZI encoding is used primarily with EIA/TIA-232 connections in IBM environments.
Examples
The following example configures serial interface 1 for NRZI encoding:
Router(config)# interface serial 1Router(config-if)# nrzi-encodingThe following example configures serial interface 3/1/0 for NRZI mark encoding:
Router(config)# interface serial 3/1/0Router(config-if)# nrzi-encoding markphysical-layer
To specify the mode of a slow-speed serial interface on a router as either synchronous or asynchronous, use the physical-layer command in interface configuration mode. To return the interface to the default mode of synchronous, use the no form of this command.
physical-layer {sync | async}
no physical-layer
Syntax Description
sync
Places the interface in synchronous mode. This is the default.
async
Places the interface in asynchronous mode.
Defaults
Synchronous mode
Command Modes
Interface configuration
Command History
Usage Guidelines
This command applies only to low-speed serial interfaces available on Cisco 2520 through 2523 series routers.
If you specify the no physical-layer command, you return the interface to its default mode (synchronous).
In synchronous mode, low-speed serial interfaces support all interface configuration commands available for high-speed serial interfaces, except the following two commands:
•
•
When placed in asynchronous mode, low-speed serial interfaces support all commands available for standard asynchronous interfaces.
When you enter this command, it does not appear in the output of more system:running-config and more nvram:startup-config commands because the command is a physical-layer command.
Examples
This example changes a low-speed serial interface from synchronous to asynchronous mode:
Router(config)# interface serial 2Router(config-if)# physical-layer asyncRelated Commands
port
To enable an interface on a PA-4R-DTR port adapter to operate as a concentrator port, use the port command in interface configuration mode. To restore the default station mode, use the no form of this command.
port
no port
Syntax Description
This command has no arguments or keywords.
Defaults
Station mode
Command Modes
Interface configuration
Command History
Usage Guidelines
By default, the interfaces of the PA-4R-DTR operate as Token Ring stations. Station mode is the typical operating mode. Use this command to enable an interface to operate as a concentrator port.
Examples
The following example configures the PA-4R-DTR ports to operate in concentrator mode on a Cisco 7000 series router:
Router# configure terminalRouter(config)# interface tokenring 3/0/0Router(config-if)# portpos ais-shut
To send the line alarm indication signal (LAIS) when the Packet-Over-SONET (POS) interface is placed in any administrative shut down state, use the pos ais-shut command in interface configuration mode.
pos ais-shut
Syntax Description
This command has no keywords or arguments.
Defaults
No LAIS is sent.
Command Modes
Interface configuration
Command History
Usage Guidelines
In Automatic Protection Switching (APS) environments, LAIS can be used to force a protection switch. This command forces an APS switch when the interface is placed in administrative shut down state.
For more information on APS, refer to the "Configuring Serial Interfaces" chapter in the Cisco IOS Interface Configuration Guide.
This command does not have a no form.
Examples
The following example forces the alarm indication on POS OC-3 interface 0 in slot 3:
Router(config)# interface pos 3/0Router(config-if)# shutdownRouter(config-if)# pos ais-shutpos flag
To set the SONET overhead bytes in the frame header to meet a specific standards requirement or to ensure interoperability with the equipment of another vendor, use the pos flag command in interface configuration mode. To remove the setting of the SONET overhead bytes, use the no form of this command.
pos flag {c2 | j0 | s1s0} value
no pos flag {c2 | j0 | s1s0} value
Syntax Description
Defaults
The default c2 value is 0xCF, and the default sls0 value is 0.
Command Modes
Interface configuration
Command History
11.2 GS
This command was introduced to support the Cisco 12000 series Gigabit Switch Routers.
Usage Guidelines
Use the following values to tell the SONET transmission equipment the payload type:
•
•
•
•
Examples
The following example sets the path signal identifier used to identify the payload content type to ATM on the pos interface in slot 9:
Router(config)# interface pos 9/0Router(config-if)# pos flag c2 0x13Router(config-if)# endRouter#pos framing
To specify the framing used on the POS (Packet-over-SONET) interface, use the pos framing command in interface configuration mode. To return to the default SONET STS-3c framing mode, use the no form of this command.
pos framing {sdh | sonet}
no pos framing
Syntax Description
sdh
Selects SDH STM-1 framing. This framing mode is typically used in Europe.
sonet
Selects SONET STS-3c framing. This is the default.
Defaults
SONET STS-3c framing
Command Modes
Interface configuration
Command History
Examples
The following example configures the interface for SDH STM-1 framing:
Router(config)# interface pos 3/0Router(config-if)# pos framing sdhRouter(config-if)# no shutdownRelated Commands
pos framing-sdh
The pos framing-sdh command is replaced by the pos framing command. See the description of the pos framing command in this chapter for more information.
pos internal-clock
The pos internal-clock command is replaced by the clock source (interface) command. See the description of the clock source (interface) command in this chapter for information on transmit clock source.
pos report
To permit selected SONET alarms to be logged to the console for a POS (Packet-Over-SONET) interface, use the pos report command in interface configuration mode. To disable logging of select SONET alarms, use the no form of this command.
pos report {b1-tca | b2-tca | b3-tca | lais | lrdi | pais | plop | prdi | rdool | sd-ber | sf-ber | slof | slos}
no pos report {b1-tca | b2-tca | b3-tca | lais | lrdi | pais | plop | prdi | rdool | sd-ber | sf-ber | slof | slos}
Syntax Description
Defaults
The following alarms are reported by default:
•
•
•
•
•
•
•
Command Modes
Interface configuration
Command History
Usage Guidelines
Reporting an alarm means that the alarm can be logged to the console. Just because an alarm is permitted to be logged does not guarantee that it is logged. SONET alarm hierarchy rules dictate that only the most severe alarm of an alarm group is reported. Whether an alarm is reported or not, you can view the current state of a defect by checking the "Active Defects" line from the show controllers pos command output. A defect is a problem indication that is a candidate for an alarm.
For B1, the bit interleaved parity error report is calculated by comparing the BIP-8 code with the BIP-8 code extracted from the B1 byte of the following frame. Differences indicate that section level bit errors have occurred.
For B2, the bit interleaved parity error report is calculated by comparing the BIP-8/24 code with the BIP-8 code extracted from the B2 byte of the following frame. Differences indicate that line level bit errors have occurred.
For B3, the bit interleaved parity error report is calculated by comparing the BIP-8 code with the BIP-8 code extracted from the B3 byte of the following frame. Differences indicate that path level bit errors have occurred.
PAIS is sent by line terminating equipment (LTE) to alert the downstream path terminating equipment (PTE) that it has detected a defect on its incoming line signal.
PLOP is reported as a result of an invalid pointer (H1, H2) or an excess number of new data flag (NDF) enabled indications.
SLOF is detected when a severely error framing (SEF) defect on the incoming SONET signal persists for 3 milliseconds.
SLOS is detected when an all-zeros pattern on the incoming SONET signal lasts 19 plus or minus 3 microseconds or longer. This defect might also be reported if the received signal level drops below the specified threshold.
To determine the alarms that are reported on the interface, use the show controllers pos command.
Examples
The following example enables reporting of SD-BER and LAIS alarms on the interface:
Router(config)# interface pos 3/0/0Router(config-if)# pos report sd-berRouter(config-if)# pos report laisRouter(config-if)# endRouter#Related Commands
Defines the IP addresses of the server, configures an interface type, and enters interface configuration mode.
Displays information about the POS controllers.
pos scramble-atm
To enable SONET payload scrambling on a POS (Packet-Over-SONET) interface, use the pos scramble-atm command in interface configuration mode. To disable scrambling, use the no form of this command.
pos scramble-atm
no pos scramble-atm
Syntax Description
This command has no arguments or keywords.
Defaults
Scrambling is disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
SONET payload scrambling applies a self-synchronous scrambler (x43+1) to the Synchronous Payload Envelope (SPE) of the interface to ensure sufficient bit transition density. Both ends of the connection must use the same scrambling algorithm. When enabling POS scrambling on a VIP2 POSIP on the Cisco 7500 series router that has a hardware revision of 1.5 or higher, you can specify CRC 16 only (that is, CRC 32 is currently not supported).
To determine the hardware revision of the POSIP, use the show diag command.
To determine whether scrambling is enabled on the interface, use the show interface pos command or the more nvram:startup-config command.
Note
Examples
The following example enables scrambling on the interface:
Router(config)# interface pos 3/0Router(config-if)# pos scramble-atmRouter(config-if)# no shutdownRouter(config-if)# endRouter#Related Commands
pos threshold
To set the bit-error rate (BER) threshold values of the specified alarms for a POS (Packet-Over-SONET) interface, use the pos threshold command in interface configuration mode. To return to the default setting, use the no form of this command.
pos threshold {b1-tca | b2-tca | b3-tca | sd-ber | sf-ber} rate
no pos threshold {b1-tca | b2-tca | b3-tca | sd-ber | sf-ber} rate
Syntax Description
Defaults
The default rate is 6 for b1-tca, b2-tca, b3-tca, and sd-ber.
The default rate is 3 (10e-3) for sf-ber.
Command Modes
Interface configuration
Command History
Usage Guidelines
For B1, the bit interleaved parity error report is calculated by comparing the BIP-8 code with the BIP-8 code extracted from the B1 byte of the following frame. Differences indicate that section level bit errors have occurred.
For B2, the bit interleaved parity error report is calculated by comparing the BIP-8/24 code with the BIP-8 code extracted from the B2 byte of the following frame. Differences indicate that line level bit errors have occurred.
For B3, the bit interleaved parity error report is calculated by comparing the BIP-8 code with the BIP-8 code extracted from the B3 byte of the following frame. Differences indicate that path level bit errors have occurred.
SF-BER and SD-BER are sourced from B2 BIP-8 error counts (as is B2-TCA). However, SF-BER and SD-BER feed into the automatic protection switching (APS) machine and can lead to a protection switch (if APS is configured).
B1-TCA, B2-TCA, and B3-TCA do nothing more than print a log message to the console (if reports for them are enabled).
To determine the BER thresholds configured on the interface, use the show controllers pos command.
Examples
The following example configures thresholds on the interface:
Router(config)# interface pos 3/0/0Router(config-if)# pos threshold sd-ber 8Router(config-if)# pos threshold sf-ber 4Router(config-if)# pos threshold b1_tca 4Router(config-if)# endRouter#Related Commands
posi framing-sdh
The posi framing-sdh command is replaced by the pos framing command. See the description of the pos framing command for more information.
pri-group
To specify ISDN PRI on a channelized E1 or T1 card on a Cisco 7500 series router, use the pri-group command in controller configuration mode. To remove the ISDN PRI, use the no form of this command.
pri-group [timeslots range]
no pri-group
Syntax Description
Defaults
Disabled
Command Modes
Controller configuration
Command History
Usage Guidelines
When you configure ISDN PRI, you must first specify an ISDN switch type for PRI and an E1 or T1 controller.
Examples
The following example specifies ISDN PRI on T1 slot 1, port 0:
Router# isdn switch-type primary-4essRouter(config)# controllers t1 1/0Router(config-controller)# framing esfRouter(config-controller)# linecode b8zsRouter(config-controller)# pri-group timeslots 2-6Related Commands
controller
Configures a T1 or E1 controller and enters controller configuration mode.
interface serial
Specifies a serial interface created on a channelized E1 or channelized T1 controller (for ISDN PRI, CAS, or robbed-bit signaling).
isdn switch-type (PRI)
Specifies the central office switch type on the ISDN PRI interface.
pulse-time
To enable pulsing data terminal ready (DTR) signal intervals on the serial interfaces, use the pulse-time command in interface configuration mode. To restore the default interval, use the no form of this command.
pulse-time [msec] seconds
no pulse-time
Syntax Description
Defaults
0 seconds
Command Modes
Interface configuration
Command History
10.0
This command was introduced.
12.1(5)T
The optional msec keyword was added to configure the DTR signal interval in milliseconds.
Usage Guidelines
When the serial line protocol goes down (for example, because of loss of synchronization), the interface hardware is reset and the DTR signal is held inactive for at least the specified interval. This function is useful for handling encrypting or other similar devices that use the toggling of the DTR signal to resynchronize.
Use the optional msec keyword to specify the DTR signal interval in milliseconds. A signal interval set to milliseconds is recommended on high-speed serial interfaces (HSSI).
Examples
The following example enables DTR pulse signals for 3 seconds on serial interface 2:
Router(config)# interface serial 2Router(config-if)# pulse-time 3The following example enables DTR pulse signals for 150 milliseconds on HSSI interface 2/1/0:
Router(config)# interface hssi 2/1/0Router(config-if)# pulse-time msec 150ring-speed
To set the ring speed for the CSC-1R and CSC-2R Token Ring interfaces, use the ring-speed command in interface configuration mode.
ring-speed speed
Syntax Description
speed
Integer that specifies the ring speed, either 4 for 4-Mbps operation or 16 for 16-Mbps operation. The default is 16.
Defaults
16-Mbps operation
Caution
Command Modes
Interface configuration
Command History
Usage Guidelines
This command does not have a no form.
Examples
The following example sets a Token Ring interface ring speed to 4 Mbps:
Router(config)# interface tokenring 0Router(config-if)# ring-speed 4scramble
To enable scrambling of the payload on the PA-E3 and PA-T3 port adapters, use the scramble command in interface configuration mode. To disable scrambling, use the no form of this command.
scramble
no scramble
Syntax Description
This command has no arguments or keywords.
Defaults
Scrambling is disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
E3/T3 scrambling is used to assist clock recovery on the receiving end.
Scrambling can prevent some bit patterns from being mistakenly interpreted as alarms by switches placed between the DSUs.
The local interface configuration must match the remote interface configuration. For example, if you enable scrambling on the local port, you must also do the same on the remote port.
To verify that scrambling is configured on the interface, use the show controllers serial EXEC command.
Examples
The following example enables scrambling on the PA-E3 port adapter in slot 1, port adapter slot 0, interface 0:
Router(config)# interface serial 1/0/0Router(config-if)# scrambleRelated Commands
sdlc cts-delay
The sdlc cts-delay command is replaced by the half-duplex timer command. See the description of the half-duplex timer command in this chapter for more information.
sdlc hdx
The sdlc hdx command is replaced by the half-duplex command. See the description of the half-duplex command in this chapter for more information.
sdlc rts-delay
The sdlc rts-delay command is replaced by the half-duplex timer command. See the description of the half-duplex timer command in this chapter for more information.
serial restart-delay
To set the amount of time that the router waits before trying to bring up a serial interface when it goes down, use the serial restart-delay command in interface configuration mode. To restore the default, use the no form of the command.
serial restart-delay count
no serial restart-delay
Syntax Description
Defaults
0 is the default value.
Command Modes
Interface configuration
Command History
11.2 P
This command was introduced.
12.0(5)XK and 12.0(7)T
Support was added for the Cisco MC3810.
Usage Guidelines
The router resets the hardware each time the serial restart timer expires. This command is often used with the dial backup feature and with the pulse-time command, which sets the amount of time to wait before redialing when a DTR dialed device fails to connect.
When the count value is set to the default of 0, the hardware is not reset when it goes down. In this way, if the interface is used to answer a call, it does not cause DTR to drop, which can cause a communications device to disconnect.
Examples
This examples shows the restart delay on serial interface 0 set to 0:
interface Serial0serial restart-delay 0Related Commands
pulse-time
Enables pulsing DTR signal intervals on the serial interfaces.
show interfaces serial
Displays information about a serial interface.
service-module 56k clock rate
To configure the network line speed for a serial interface on a 4-wire, 56/64-kbps CSU/DSU module, use the service-module 56k clock rate command in interface configuration mode. To enable a network line speed of 56 kbps, which is the default, use the no form of this command.
service-module 56k clock rate speed
no service-module 56k clock rate speed
Syntax Description
Defaults
56 kbps
Command Modes
Interface configuration
Command History
Usage Guidelines
The 56-kbps line speed is available in switched mode, which is enabled using the service-module 56k network-type interface configuration command on the 4-wire CSU/DSU. If you have a 2-wire CSU/DSU module, the default is automatically set to switched mode.
The 64-kbps line speed cannot be used with back-to-back digital data service (DDS) lines. The subrate line speeds are determined by the service provider.
The auto keyword enables the CSU/DSU to decipher current line speed from the sealing current running on the network. Use the auto keyword only when transmitting over telco DDS lines and the clocking source is taken from the line.
Examples
The following example displays two routers connected in back-to-back DDS mode. However, notice that at first the configuration fails because the auto option is used. Later in the example the correct matching configuration is issued, which is 38.4 kbps.
Router1(config)# interface serial 0Router1(config-if)# service-module 56k clock source internalRouter1(config-if)# service-module 56k clock rate 38.4Router2(config-if)# service-module 56k clock rate autoa1# ping 10.1.1.2Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:.....Success rate is 0 percent (0/5)Router2(config-if)# service-module 56k clock rate 38.4Router1# ping 10.1.1.2Type escape sequence to abort.Sending 5, 100-byte ICMP Echos to 10.1.1.2, timeout is 2 seconds:!!!!!Success rate is 100 percent (5/5), round-trip min/avg/max = 52/54/56 msWhen transferring from DDS mode to switched mode, you must set the correct clock rate, as shown in the following example:
Router2(config-if)# service-module 56k network-type ddsRouter2(config-if)# service-module 56k clock rate 38.4Router2(config-if)# service-module 56k network-type switched% Have to use 56k or auto clock rate for switched mode% Service module configuration command failed: WRONG FORMAT.Router2(config-if)# service-module 56k clock rate auto% WARNING - auto rate will not work in back-to-back DDS.Router2(config-if)# service-module 56k network-type switchedRelated Commands
service-module 56k clock source
To set up the clock source on a serial interface for a 4-wire, 56/64-kbps CSU/DSU module, use the service-module 56k clock source command in interface configuration mode. To specify that the clocking come from line, use the no form of this command.
service-module 56k clock source {line | internal}
no service-module 56k clock source {line | internal}
Syntax Description
line
Uses the clocking provided by the active line coming in to the router. This is the default.
internal
Uses the internal clocking provided by the hardware module.
Defaults
Line clock
Command Modes
Interface configuration
Command History
Usage Guidelines
In most applications, the CSU/DSU should be configured with the clock source line command. For back-to-back configurations, configure one CSU/DSU with the clock source internal command and the other with clock source line command.
Examples
The following example configures internal clocking and transmission speed at 38.4 kbps.
Router(config)# interface serial 0Router(config-if)# service-module 56k clock source internalRouter(config-if)# service-module 56k clock rate 38.4Related Commands
Controls the clock used by a G.703-E1 interface.
Configures the network line speed for a serial interface on a 4-wire, 56/64-kbps CSU/DSU module.
service-module 56k data-coding
To prevent application data from replicating loopback codes when operating at 64 kbps on a 4-wire CSU/DSU, use the service-module 56k data-coding command in interface configuration mode. To enable normal transmission, use the no form of this command.
service-module 56k data-coding {normal | scrambled}
no service-module 56k data-coding {normal | scrambled}
Syntax Description
Defaults
Normal data transmission
Command Modes
Interface configuration
Command History
Usage Guidelines
Enable the scrambled configuration only in 64-kbps digital data service (DDS) mode. If the network type is set to switched, the configuration is refused.
If you transmit scrambled bit codes, both CSU/DSUs must have this command configured for successful communication.
Examples
The following example scrambles bit codes or user data before transmission:
Router(config)# interface serial 0Router(config-if)# service-module 56k clock rate 64Router(config-if)# service-module 56k data-coding scrambledRelated Commands
Configures the network line speed for a serial interface on a 4-wire, 56/64-kbps CSU/DSU module.
service-module 56k network-type
To transmit packets in switched dial-up mode or digital data service (DDS) mode using a serial interface on a 4-wire, 56/64-kbps CSU/DSU module, use the service-module 56k network-type command in interface configuration mode. To transmit from a dedicated leased line in DDS mode, use the no form of this command.
service-module 56k network-type {dds | switched}
no service-module 56k network-type {dds | switched}
Syntax Description
Defaults
DDS is enabled for the 4-wire CSU/DSU.
Switched is enabled for the 2-wire CSU/DSU.
Command Modes
Interface configuration
Command History
Usage Guidelines
In switched mode, you need additional dialer configuration commands to configure dial-out numbers. Before you enable the service-module 56k network-type switched command, both CSU/DSUs must use a clock source coming from the line and have the clock rate configured to auto or 56 kbps. If the clock rate is not set correctly, this command will not be accepted.
The 2-wire and 4-wire, 56/64-kbps CSU/DSU modules use V.25 bis dial commands to interface with the router. Therefore, the interface must be configured using the dialer in-band command. Data terminal ready (DTR) dial is not supported.
Note
Examples
The following example configures transmission in switched dial-up mode:
Router(config)# interface serial 0Router(config-if)# service-module 56k clock rate autoRouter(config-if)# service-module 56k network-type switchedRouter(config-if)# dialer in-bandRouter(config-if)# dialer string 5551111Router(config-if)# dialer-group 1Related Commands
service-module 56k remote-loopback
To enable the acceptance of a remote loopback request on a serial interface on a 2- or 4-wire, 56/64-kbps CSU/DSU module, use the service-module 56k remote-loopback command in interface configuration mode. To disable the module from entering loopback, use the no form of this command.
service-module 56k remote-loopback
no service-module 56k remote-loopback
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Interface configuration
Command History
Usage Guidelines
The no service-module 56k remote-loopback command prevents the local CSU/DSU from being placed into loopback by remote devices on the line. The line provider is still able to put the module into loopback by reversing sealing current. Unlike the T1 module, the 2- or 4-wire, 56/64-kbps CSU/DSU module can still initiate remote loopbacks with the no form of this command configured.
Examples
The following example enables transmitting and receiving remote loopbacks:
Router(config)# interface serial 0Router(config-if)# service-module 56k remote-loopbackRelated Commands
Loops packets through a CSU/DSU, over a DS3 link or a channelized T1 link, to the remote CSU/DSU and back.
service-module 56k switched-carrier
To select a service provider to use with a 2- or 4-wire, 56/64-kbps dial-up serial line, use the service-module 56k switched-carrier command in interface configuration mode. To enable the default service provider, use the no form of this command.
service-module 56k switched-carrier {att | sprint | other}
no service-module 56k switched-carrier {att | sprint | other}
Syntax Description
Defaults
ATT is enabled on the 4-wire, 56/64-kbps CSU/DSU module.
Sprint is enabled on the 2-wire, switched 56-kbps CSU/DSU module.
Command Modes
Interface configuration
Command History
Usage Guidelines
On a Sprint network, echo-canceler tones are sent during call setup to prevent the echo cancelers from damaging digital data. The transmission of echo-canceler tones may increase call setup times by 8 seconds on the 4-wire module. Having echo cancellation enabled does not affect data traffic.
This configuration command is ignored if the network type is DDS.
Examples
The following example configures AT&T as a service provider:
Router(config)# interface serial 0Router(config-if)# service-module 56k network-type switchedRouter(config-if)# service-module 56k switched-carrier attRelated Commands
Sends packets in switched dial-up mode or DDS mode using a serial interface on a 4-wire, 56/64-kbps CSU/DSU module.
service-module t1 clock source
To specify the clock source for the fractional T1/T1 CSU/DSU module, use the service-module t1 clock source command in interface configuration mode. To return to the default line clock, use the no form of this command.
service-module t1 clock source {internal | line}
no service-module t1 clock source {internal | line}
Syntax Description
Defaults
Line clock
Command Modes
Interface configuration
Command History
Examples
The following example sets an internal clock source on serial line 0:
Router(config)# interface serial 0Router(config-if)# service-module t1 clock source lineRelated Commands
Sets up the clock source on a serial interface for a 4-wire, 56/64-kbps CSU/DSU module.
service-module t1 data-coding
To guarantee the ones density requirement on an alternate mark inversion (AMI) line using the fractional T1/T1 module, use the service-module t1 data-coding command in interface configuration mode. To enable normal data transmission, use the no form of this command.
service-module t1 data-coding {inverted | normal}
no service-module t1 data-coding {inverted | normal}
Syntax Description
inverted
Inverts bit codes by changing all 1 bits to 0 bits and all 0 bits to 1 bits.
normal
Requests that no bit codes be inverted before transmission. This is the default.
Defaults
Normal transmission
Command Modes
Interface configuration
Command History
Usage Guidelines
Data inversion is used to guarantee the ones density requirement on an AMI line when using bit-oriented protocols such as High-Level Data Link Control (HDLC), PPP, X.25, and Frame Relay. If the time slot speed is set to 56 kbps, this command is rejected because line density is guaranteed when transmitting at 56 kbps. Use this command with the 64-kbps line speed.
If you transmit inverted bit codes, both CSU/DSUs must have this command configured for successful communication.
Examples
The following example inverts bit codes using a time slot speed of 64 kbps:
Router(config)# interface serial 0Router(config-if)# service-module t1 timeslots all speed 64Router(config-if)# service-module t1 data-coding invertedRelated Commands
Selects the linecode for the fractional T1/T1 module.
Defines time slots that constitute a fractional T1/T1 (FT1/T1) channel.
service-module t1 fdl
To set the FDL parameter to either ATT or ANSI, use the service-module t1 fdl command in interface configuration mode. To ignore the FDL parameter, use the no form of this command.
service-module t1 fdl {ansi | att}
no service-module t1 fdl
Syntax Description
Defaults
Determined by the telephone company.
Command Modes
Interface configuration mode
Command History
Usage Guidelines
The default is no service-module t1 fdl. The ansi or att options are determined by your service provider or telephone company.
service-module t1 framing
To select the frame type for a line using the fractional T1/T1 (FT1/T1) module, use the service-module t1 framing command in interface configuration mode. To revert to the default, Extended Super Frame, use the no form of this command.
service-module t1 framing {esf | sf}
no service-module t1 framing {esf | sf}
Syntax Description
esf
Specifies Extended Super Frame as the T1 frame type. This is the default.
sf
Specifies D4 Super Frame as the T1 frame type.
Defaults
Extended Super Frame (ESF)
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command in configurations in which the router communicates with FT1/T1 data lines. The service provider determines which framing type, either esf or sf, is required for your circuit.
Examples
The following example enables Super Frame as the FT1/T1 frame type:
Router(config-if)# service-module t1 framing sfservice-module t1 lbo
To configure the CSU line-build-out (LBO) on a fractional T1/T1 CSU/DSU module, use the service-module t1 lbo command in interface configuration mode. To disable line-build-out, use the no form of this command.
service-module t1 lbo {-15 db | -7.5 db | none}
no service-module t1 lbo {-15 db | -7.5 db | none}
Syntax Description
-15 db
Decreases outgoing signal strength by 15 dB.
-7.5 db
Decreases outgoing signal strength by 7.5 dB.
none
Transmits packets without decreasing outgoing signal strength.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Use this command to decrease the outgoing signal strength to an optimum value for a fractional T1 line receiver. The ideal signal strength should be -15 dB to -22 dB, which is calculated by adding the phone company loss, cable length loss, and line build out.
You may use this command in back-to-back configurations, but it is not needed on most actual T1 lines.
Examples
The following example sets the LBO to -7.5 dB:
Router(config)# interface serial 0Router(config-if)# service-module t1 lbo -7.5 dbservice-module t1 linecode
To select the line code for the fractional T1/T1 module, use the service-module t1 linecode command in interface configuration mode. To select the default, the B8ZS line code, use the no form of this command.
service-module t1 linecode {ami | b8zs}
no service-module t1 linecode {ami | b8zs}
Syntax Description
ami
Specifies alternate mark inversion (AMI) as the line code.
b8zs
Specifies binary 8 zero substitution (B8ZS) as the line code. This is the default.
Defaults
The default line code is B8ZS.
Command Modes
Interface configuration
Command History
Usage Guidelines
Configuring B8ZS is a method of ensuring the ones density requirement on a T1 line by substituting intentional bipolar violations in bit positions four and seven for a sequence of eight zero bits. When the CSU/DSU is configured for AMI, you must guarantee the ones density requirement in your router configuration using the service-module t1 data-coding inverted command or the service-module t1 time slots speed 56 command.
Your T1 service provider determines which line code, either ami or b8zs, is required for your T1 circuit.
Examples
The following example specifies AMI as the line code:
Router(config)# interface serial 0Router(config-if)# service-module t1 linecode amiRelated Commands
Guarantees the ones density requirement on an AMI line using the fractional T1/T1 module.
Defines time slots that constitute a fractional T1/T1 (FT1/T1) channel.
service-module t1 remote-alarm-enable
To generate remote alarms (yellow alarms) at the local CSU/DSU or detect remote alarms sent from the remote CSU/DSU, use the service-module t1 remote-alarm-enable command in interface configuration mode. To disable remote alarms, use the no form of this command.
service-module t1 remote-alarm-enable
no service-module t1 remote-alarm-enable
Syntax Description
This command has no arguments or keywords.
Defaults
Remote alarms are disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Remote alarms are transmitted by the CSU/DSU when it detects an alarm condition, such as a red alarm (loss of frame) or blue alarm (unframed ones). The receiving CSU/DSU then knows that there is an error condition on the line.
With D4 Super Frame configured, a remote alarm condition is transmitted by setting the bit 2 of each time slot to zero. For received user data that has the bit 2 of each time slot set to zero, the CSU/DSU interprets the data as a remote alarm and interrupts data transmission, which explains why remote alarms are disabled by default. With Extended Super Frame configured, the remote alarm condition is signalled out of band in the facilities data link.
You can see if the FT1/T1 CSU/DSU is receiving a remote alarm (yellow alarm) by issuing the show service-module command.
Examples
The following example enables remote alarm generation and detection:
Router(config)# interface serial 0Router(config-if)# service-module t1 remote-alarm-enableRelated Commands
service-module t1 remote-loopback
To specify if the fractional T1/T1 CSU/DSU module enters loopback mode when it receives a loopback code on the line, use the service-module t1 remote-loopback command in interface configuration mode. To disable remote loopbacks, use the no form of this command.
service-module t1 remote-loopback {full | payload} [alternate | v54]
no service-module t1 remote-loopback {full | payload}
Syntax Description
Note
Defaults
Full and payload loopbacks with standard-loopup codes
Command Modes
Interface configuration
Command History
Usage Guidelines
You can simultaneously configure the full and payload loopback points. However, only one loopback code can be configured at a time. For example, if you configure the service-module t1 remote-loopback payload alternate command, a payload v54 request cannot be transmitted or accepted.
The no form of this command disables loopback requests. For example, the no service-module t1 remote-loopback full command ignores all full-bandwidth loopback transmissions and requests. Configuring the no form of this command may not prevent telco line providers from looping your router in esf mode, because fractional T1/T1 lines use facilities data link messages to initiate loopbacks.
If you enable the service-module t1 remote-loopback command, the loopback remote commands on the FT1/T1 CSU/DSU module will not be successful.
Examples
The following example displays two routers connected back-to-back through a fractional T1/T1 line:
Router# no service-module t1 remote-loopback fullRouter# service-module t1 remote-loopback payload alternateRouter# loopback remote full%SERVICE_MODULE-5-LOOPUPFAILED: Unit 0 - Loopup of remote unit failedRouter# service-module t1 remote-loopback payload v54Router# loopback remote payload%SERVICE_MODULE-5-LOOPUPFAILED: Unit 0 - Loopup of remote unit failedRouter# service-module t1 remote-loopback payload alternateRouter# loopback remote payload%SERVICE_MODULE-5-LOOPUPREMOTE: Unit 0 - Remote unit placed in loopbackRelated Commands
Loops packets through a CSU/DSU, over a DS3 link or a channelized T1 link, to the remote CSU/DSU and back.
