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Cisco IOS Interface and Hardware Component Command Reference
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Introduction
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A through B
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cable bundle through clock mode
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clock rate through cut-through
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D through E
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F through H
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I through K
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l2 vfi manual through loopback (PA-MC-8TE1 + port adapter)
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loopback (T1 interface) through nrzi-encoding
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O through R
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scramble through service-module t1 lbo
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service-module t1 linecode through show controllers satellite
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show controllers serial through show hw-module slot proc cpu
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show hw-module slot tech-support through show interfaces vg-anylan
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show interfaces vlan mapping through show scp
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show service-module serial through standby port
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squelch through system jumbomtu
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t1 through tug-2 e1 unframed
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tunnel bandwidth through yellow
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Table Of Contents
clock source (SONET controller)
clock source (T1/E1 controller)
clock source (T1/E1 interface)
clock source (T3/E3 controller)
clock rate
To configure the clock rate for the hardware connections on serial interfaces such as network interface modules (NIMs) and interface processors to an acceptable bit rate, use the clock rate command in interface configuration mode. To remove the clock rate if you change the interface from a DCE to a DTE device, use the no form of this command. Using the no form of this command on a DCE interface sets the clock rate to the hardware-dependent default value.
clock rate bps
no clock rate
Syntax Description
Defaults
No clock rate is configured.
Command Modes
Interface configuration
Command History
Usage Guidelines
Cable Length
Be aware that the fastest speeds might not work if your cable is too long, and that speeds faster than 148,000 bits per second are too fast for EIA/TIA-232 signaling. It is recommended that you only use the synchronous serial EIA/TIA-232 signal at speeds up to 64,000 bits per second. To permit a faster speed, use EIA/TIA-449 or V.35.
Synchronous Serial Port Adapters
For the synchronous serial port adapters (PA-8T-V35, PA-8T-X21, PA-8T-232, and PA-4T+) on Cisco 7200 series routers, and on second-generation Versatile Interface Processors (VIP2s) in Cisco 7500 series routers, the clock rate you enter is rounded (if needed) to the nearest value that your hardware can support. To display the clock rate value for the port adapter, use the show running-config command.
If you plan to netboot your router over a synchronous serial port adapter interface and have a boot image prior to Cisco IOS Release 11.1(9)CA that does not support nonstandard (rounded) clock rates for the port adapters, you must use one of the following standard clock rates:
•
1200
•
•
•
•
•
•
•
Examples
The following example shows how to set the clock rate on the first serial interface to 64,000 bps:
Router(config)# interface serial 0Router(config-if)# clock rate 64000The following example shows how to set the clock rate on a synchronous serial port adapter in slot 5, port 0 to 1,234,567 bps. In this example, the clock rate is adjusted to 1,151,526 bps.
Router(config)# interface serial 5/0Router(config-if)# clock rate 1234567%Clockrate rounded to nearest value that your hardware can support.The following example shows how to determine the exact clock rate that the serial interface was rounded to by using the show running-config command.
Router# show running-configBuilding configuration......!interface Serial5/0no ip addressclockrate 1151526!...clock rate (interface ATM)
To configure the clock rate between a WAN interface card (WIC) and the serial communication controllers (SCCs) that are used by the WIC, use the clock rate command in interface ATM configuration mode. To disable the clock rate setting, use the no form of this command.
clock rate [aal2 | aal5] clock-rate-value
no clock rate [aal2 | aal5] clock-rate-value
Syntax Description
Defaults
No clock rate is set
Command Modes
Interface ATM configuration
Command History
Usage Guidelines
The communication between digital subscriber line (DSL) WICs and a host in a router occurs through a device called the SCC. If a host wants to forward data or send any control traffic to a DSL WIC, it uses SCCs. In the same way, if a DSL WIC wants to forward incoming data from a line to the host, it also uses SCCs. Each DSL WIC installed in the router uses two SCCs. One SCC (SCC-A) is used for AAL5 data traffic, and the other SCC (SCC-B) is used for AAL2 and control traffic. The speed at which the SCC transfers data between a host and a WIC depends on the clock rate with which it has been configured. You can configure this clock rate on the basis of the DSL line rate. Even though the DSL upstream and downstream line rate may vary, the clock rate between the SCC and the DSL WIC is the same for both the transmitting and receiving direction. That is, the communication between the SCC and the DSL WIC is synchronous. Therefore, you need to configure only one clock rate for an SCC that will be used for both transmitting and receiving between an SCC and a DSL WIC.
We always recommend that you configure the SCC clock rate slightly higher than the DSL line rate to accommodate overhead between the SCC and the DSL WIC. For an asynchronous DSL WIC (for example, ADSL), the SCC clock rate depends on either the downstream or the upstream line rate, whichever is the maximum rate. For a synchronous DSL WIC (for example, G.SHDSL), the bandwidth for upstream and downstream is the same. Therefore, the SCC clock rate configuration can be based on either the upstream or the downstream line rate.
Because the maximum line rate for G.SHDSL is 2.312 Mbps, the default SCC clock rate of 2.6 Mbps for AAL5 and 1 Mbps for AAL2 should be sufficient. However, for ADSL, the clock rate may need to be configured on the basis of the current line rate. If AAL2 is used for voice traffic, the AAL2 SCC must be configured to the appropriate clock rate: 1 Mbps for ADSL and 2.6 Mbps for G.SHDSL.
The maximum data rate between an SCC and a DSL WIC depends primarily on the maximum clock rate that the SCC can support. For example, on the Cisco 2600 series mainboard, which supports two DSL WICs, the total SCC clock rate that can be configured for both WICs is 8 Mbps. Therefore, if only one DSL WIC is present on the mainboard, AAL5 and AAL2 clock rates can be configured to 7 Mbps and 1 Mbps, respectively. If two DSL WICs are supported on the mainboard, the total of 8 Mbps should be distributed among the four SCCs.
Network module SCCs also pose similar limitations. That is, on the Cisco 2600 series, the total clock rate for all four SCCs is 8 Mbps. The maximum AAL5 clock rate that may be configured on a network module is 5.3 Mbps. On the Cisco 1700 series, the maximum configurable SCC clock rate for both AAL5 and AAL2 is 8 Mbps.
If the clock rate is not configured, the SCC is reset to the default values.
The clock rate can be configured independently for each SCC. To verify the clock rate setting, use the show running-config command.
Examples
The following example shows how to set the clock rate to 2 Mbps for AAL5 and to 1.3 Mbps for AAL2 for a Cisco 2600 or Cisco 3600 series router:
Router (config)# interface atm1/0Router (config-if)# no ip addressRouter (config-if)# no atm ilmi-keepaliveRouter (config-if)# pvc 6/65Router (config-if)# clock rate aal5 2000000Router (config-if)# clock rate aal2 1300000Router (config-if)# vbr-nrt 640 640 128Router (config-if)# tx-ring-limit 3Related Commands
clock rate (interface serial)
To configure the clock rate for the hardware connections on serial interfaces, such as network interface modules (NIMs) and interface processors, to an acceptable bit rate, use the clock rate command in interface configuration mode or Circuit Emulation Module (CEM) configuration mode. To remove the clock rate if you change the interface from a DCE to a DTE device, use the no form of this command. Using the no form of this command on a DCE interface sets the clock rate to the hardware-specific default value.
clock rate {line | rate}
no clock rate
Syntax Description
Defaults
No clock rate is configured.
Command Modes
Interface configuration
CEM configuration in Circuit Emulation Module (CEM)Command History
Usage Guidelines
Using the no form of this command on a DCE interface sets the clock rate to the hardware-dependent default value.
Cable Length
Be aware that the fastest speeds might not work if your cable is too long and that speeds faster than 148,000 bits per second are too fast for EIA/TIA-232 signaling. It is recommended that you use the synchronous serial EIA/TIA-232 signal at speeds up to 64,000 bits per second only. To permit a faster speed, use EIA/TIA-449 or V.35.
Synchronous Serial Port Adapters
For the synchronous serial port adapters (PA-8T-V35, PA-8T-X21, PA-8T-232, and PA-4T+) on Cisco 7200 series routers and on second-generation Versatile Interface Processors (VIP2s) in Cisco 7500 series routers, the clock rate that you enter is rounded (if needed) to the nearest value that your hardware can support. To display the clock rate value for the port adapter, use the show running-config command.
If you plan to boot from a network (TFTP) server over a synchronous serial port adapter interface and have a boot image prior to Cisco IOS Release 11.1(9)CA that does not support nonstandard (rounded) clock rates for the port adapters, you must use one of the following standard clock rates:
1200, 2400, 4800, 9600, 19200, 38400, 56000, 64000
CEM Network Modules
The following clock rates are supported on CEM Network Modules:
200, 300, 400, 600, 800, 1200, 1800, 2400, 3200, 3600, 4800, 6400, 7200, 8000, 9600, 12000, 12800, 14400, 16000, 16800, 19200, 24000, 28800, 32000, 38400, 48000, 56000, 57600, 64000, 76800, 84000, 96000, 112000, 115200, 128000, 144000, 168000, 192000, 224000, 230400, 256000, 288000, 336000, 384000, 448000, 512000, 672000, 768000, 772000, 896000, 1024000, 1152000, 1344000, 1536000, 1544000, 1792000, 1920000, 2048000
Examples
Network as Clock Source Example
The following example shows how to set the clock rate to use the network as the clock source:
Router(config)# interface serial 0Router(config-if)# clock rate lineClock Rate on Synchronous Serial Port Example
The following example shows how to set the clock rate on a synchronous serial port adapter in slot 5, port 0 to 1,234,567 bps. In this example, the clock rate is adjusted to 1,151,526 bps.
Router(config)# interface serial 5/0Router(config-if)# clock rate 1234567%Clockrate rounded to nearest value that your hardware can support.Clock Rate Rounded on Serial Enterface Example
The following example shows how to determine the exact clock rate that the serial interface was rounded to by using the show running-config command.
Router# show running-configBuilding configuration......!interface Serial5/0no ip addressclockrate 1151526!CEM Channel Example
This example shows the statistics for the current CEM configuration.
Router# show cem 4/1/0cem infocem 4/1/0 is upLine state is upOperational state is activeNear end ip address: 172.31.28.2, udp port: 15901Far end ip address: 172.31.28.10, udp port: 15901IP payload size: 512IP dscp : 0x28Idle pattern length: 8 , Idle Pattern: 0xFFPayload compression is disabledData protection is disabledDejitter buffer size is 60 msChannel clock rate is 2048000 bpsPhysical interface is E1 unframedIngress packets: 32505156, dropped: 0, overruns: 0Egress packets: 32505158, dropped: 637, lost pkts: 0Egress out of sequence pkts: 0Egress overruns: 16, underruns: 244Egress corrupt pkts rcvd: 030 second ingress rate 2050321 bits/sec, 500 packets/sec30 second egress rate 2050184 bits/sec, 500 packets/secTx interrupts: 32504249Reorder queue flush: 0, visited: 0, max wait window: 0Network jitter max: 8 ms, average: 1 ms, min: 0 msAdaptive clock ppm correction is 2 trackingEvent history: 0x00230058Pkts dropped by burst limit: 0Global stats for slot 4************************Egr free buf: 255Egr host overruns: 0Egr unknown dest count: 0Last unknown dest ip : 0.0.0.0, port: 0Last unknown dest src ip : 0.0.0.0, port: 0Egr process switched: 0Egr oos: 0Egr unknown src count: 0, last unknown src ip: 0.0.0.0, port: 0Ingr overruns: 0NM cpu: 53.56 53.51 53.45 53.54Related Commands
show running-config
Displays the current configuration.
show cem
Displays circuit emulation statistics.
clock rate network-clock
To configure the network clock rate (speed) for serial ports 0 or 1 in DCE mode, use the clock rate network-clock command in interface configuration mode. To cancel the network clock rate value, use the no form of this command.
clock rate network-clock rate
no clock rate network-clock rate
Syntax Description
rate
Network clock rate, in kbps per second. The range is from 56 to 2048. The value entered should be a multiple of the value set for the network-clock base-rate command. There is no default rate.
Defaults
No clock rate is set.
Command Modes
Interface configuration
Command History
11.3(1)MA
This command was introduced on the Cisco MC3810 multiservice access concentrator.
Usage Guidelines
This command uses a synchronized clock on the serial port. The use of this command allows the clock on the serial port to be synchronized with the clock source of controller T1 0.
To configure the clock rate for a serial port in DTE mode, use the clock rate line command.
Examples
The following example shows how to configure the clock rate on serial port 1 in DCE mode:
Router(config)# interface serial 1Router(config-if)# clock rate network-clock 2048Related Commands
clock source
To configure the clock source of a DS1 link, enter the clock source command in interface configuration, controller configuration, or ATM interface configuration mode. To restore the default line setting, use the no form of this command.
clock source {line | internal | loop-timed}
no clock source
Syntax Description
Defaults
The default value is line.
Command Modes
Interface configuration
Controller configuration for the Cisco MC3810 multiservice access concentrator.
ATM interface configuration for the Cisco 2600 and 3600 series routers.
Command History
Usage Guidelines
This command sets clocking for individual T1/E1 links.
Make sure that you specify the clock source correctly for each link, even if you are planning to specify that a certain link will provide clocking for all the links in an IMA group. Because links may be taken in and out of service, requiring that the system select another link for common clocking, any link in an IMA group may provide the common clock.
If the ATM interface is part of an IMA group, you can use the loop-timed keyword to specify that the clock source is the same as the IMA group clock source.
Examples
On a Cisco 2600 or 3600 series router, the following example specifies an internal clock source for the link:
Router(config)# interface atm 0/2Router(config-if)# clock source internalRelated Commands
clock source(10GE)
To specify the clock source of a 10 Gigabit Ethernet (GE) line card, use the clock source command in interface configuration mode. To restore the clock source to its default setting, use the no form of this command.
clock source {internal | line | loop}
no clock source {internal | line | loop}
Syntax Description
internal
Uses the internal clock. This is the default.
line
Recovers the clock from the line.
loop
Uses local loop timing.
Command Default
The default is internal.
Command Modes
Interface configuration (config-if)
Command History
12.2(33)SRD1
This command was introduced for the 7600-ES+ITU-2TG and 7600-ES+ITU-4TG.
Usage Guidelines
When the clock source is internal, the port receive (Rx) clock is not eligible as the system clock source. The port transmit (Tx) clock is synchronized to the system clock.
When the clock source is line, the port Rx clock is eligible as the system clock source. The port Tx clock is synchronized to the system clock.
When the clock source is loop, the port Rx clock is not eligible as the system clock source. The port Tx clock is synchronized to its own Rx clock.
Examples
The following example shows how to specify line timing as the clock source:
Router(config)# interface TenGigabitEthernet 1/1Router(config-if)# clock source lineThe following example shows how to specify the internal clock on the interface provided by the 7600-ES+ITU-2TG or the 7600-ES+ITU-4TG:
Router(config)# interface TenGigabitEthernet 1/1Router(config-if)# clock source internal
Related Commands
clock source (AS5200)
To select the clock source for the time-division multiplexing (TDM) bus in a Cisco AS5200 access server, use the clock source command in interface configuration mode. To restore the clock source to its default setting, use the no form of this command.
clock source {line {primary | secondary} | internal}
no clock source line {primary | secondary}
Syntax Description
Defaults
The primary TDM clock source is from the T1 0 controller.
The secondary TDM clock source is from the T1 1 controller.
Command Modes
Interface configuration
Command History
Usage Guidelines
To use the clocking coming in from a T1 line, configure the clock source line primary command on the T1 interface that has the most reliable clocking. Configure the clock source line secondary command on the T1 interface that has the next best known clocking. With this configuration, the primary line clocking is backed up to the secondary line if the primary clocking shuts down.
Examples
The following example configures the Cisco AS5200 access server to use T1 controller 0 as the primary clock source and T1 controller 1 as the secondary clock source:
Router(config)# controller t1 0Router(config-controller)# clock source line primaryRouter(config)# controller t1 1Router(config-controller)# clock source line secondaryclock source (CEM)
To configure the clock source of a circuit emulation (CEM) network module port, use the clock source command in CEM configuration mode or controller configuration mode. To return to the default clock source, use the no form of this command.
Cisco NM-CEM-4SER
clock source {internal | loop | adaptive}
no clock source {internal | loop | adaptive}
Cisco NM-CEM-4TE1
clock source {internal | line | adaptive channel-number [closed-loop | open-loop | coarse]}
no clock source {internal | line | adaptive channel-number [closed-loop | open-loop | coarse]}
Syntax Description
Command Default
Cisco NM-CEM-4SER
The clock source defaults to internal.
Cisco NM-CEM-4TE1
The clock source defaults to line.
Command Modes
Cisco NM-CEM-4SER
CEM configuration
Cisco NM-CEM-4TE1
Controller configuration
Command History
12.3(7)T
This command was introduced.
12.4(2)T
The closed-loop, open-loop, and coarse keywords were added.
Usage Guidelines
When clock source internal is specified, the clocks provided by the network module are derived from either of the following source:
•
•
When the adaptive keyword is specified, the clocks provided by the network module are derived from the same source as in the clock source internal case. However, the derived frequency is further adjusted up or down on the basis of the measured average fill of the egress dejitter buffer of the connection. If the dejitter buffer is perceived to be slowly filling, the frequency is adjusted slightly upward. If the dejitter buffer is perceived to be slowly depleting, the frequency is adjusted slightly downward.
Cisco NM-CEM-4SER
When the loop keyword is specified, the clock provided by the NM-CEM-4SER is the same as the clock provided to the NM-CEM-4SER from the attached CPE. The specification of clock source loop is only valid when the clock mode split command is specified. The clock mode command is used only during configuration of the NM-CEM-4SER.
Cisco NM-CEM-4TE1
In Cisco IOS Release 12.4(2)T, the adaptive clocking algorithm is enhanced to provide better adaptive clock accuracy. Three new keywords are used to specify the preferred mode:
•
Note
•
•
Examples
The following example shows how to configure the clock source for the serial CEM network module, NM-CEM-4SER:
Router(config-cem)# clock source loopThe following example shows how to configure the clock source for the T1/E1 CEM network module, NM-CEM-4TE1:
Router(config-controller)# clock source adaptive 6The following example shows how to configure the clock source for an NM-CEM-4TE1 using the closed-loop mode to improve the adaptive clock accuracy:
Router(config-controller)# clock source adaptive 5 closed-loopRelated Commands
cem
Enters circuit emulation configuration mode.
clock mode
Configures the clock mode on an NM-CEM-4SER network module.
show cem
Displays CEM channel statistics.
clock source (controller)
To set the T1 line clock source, use the clock source command in controller configuration mode. To restore the clock source to its default setting, use the no form of this command.
Cisco 7200 and Cisco 7500 Series Routers
clock source [line {primary | secondary} | internal]
no clock source
Cisco 10000 Series Router
clock source [line | internal]
no clock source
Syntax Description
Defaults
Cisco 7200 and Cisco 7500 Series Routers
The default clock source is line.
The default primary TDM clock source is from the T0 controller.
The default secondary TDM clock source is from the T1 controller.
The default clock for the interface's transmitted data is from a clock recovered from the line's receive data stream from the PA-T3 serial port adapter.Cisco 10000 Series Router
The default clock source is internal.
Command Modes
Controller configuration
Command History
Usage Guidelines
This command is available on Cisco 4000, Cisco 7000 series, Cisco 7200 series, Cisco 7500 series, and Cisco 10000 series routers. A T3 interface on a PA-T3 serial port adapter can clock its transmitted data either from its internal clock or from a clock recovered from the line's receive data stream.
Clocking on a T1 Line
To use the clocking coming in from a T1 line, configure the clock source line primary command on the controller that has the most reliable clocking. Configure the clock source line secondary command on the controller that has the next best known clocking. With this configuration, the primary line clocking is backed up to the secondary line if the primary clocking shuts down.
Cisco 10000 Series Router
The clock source cannot be specified as line on both ends of the connection.
Examples
Cisco 7200
The following example shows how to configure the Cisco 7200 to use the T0 controller as the primary clocking source and the T1 controller as the secondary clocking source:
C7200(config)# controller t1 0C7200(config-controller)# clock source line primaryC7200(config-controller)# exitC7200(config)# controller t1 1C7200(config-controller)# clock source line secondaryCisco 10000 Series Router
The following example instructs the controller to use a line clock source:
Router(config)# controller dsx3 4/0/6Router(config-controller)# clock source lineRelated Commands
framing
Selects the frame type for the T1 or E1 data line.
linecode
Selects the line code type for T1 or E1 line.
clock source (CT3IP)
To specify where the clock source is obtained for use by the Channelized T3 Interface Processor (CT3IP) in Cisco 7500 series routers, use the clock source command in controller configuration mode. To restore the default clock source, use the no form of this command.
clock source {internal | line | loop-timed}
no clock source
Syntax Description
Defaults
The internal clock source is used.
Command Modes
Controller configuration
Command History
Usage Guidelines
If you do not specify the clock source command, the default internal clock source is used by the CT3IP.
You can also set the clock source for each T1 channel by using the t1 clock source controller configuration command.
Note
Examples
The following example sets the clock source for the CT3IP to line:
Router(config)# controller t3 9/0/0Router(config-controller)# clock source lineRelated Commands
clock source (interface)
To control the clock from which a G.703-E1 interface, an E1-G.703/G.704 serial port adapter, or a PA-E3 serial port adapter clocks its transmitted data, use the clock source command in interface configuration mode. To restore the default clock source, use the no form of this command.
Cisco 7000, Cisco 7200, and Cisco 7500 Series
clock source {line | internal}
no clock source
Cisco AS5300 Access Servers
clock source {line {primary | secondary} | internal}
no clock source line {primary | secondary}
Syntax Description
Defaults
Cisco 7000, Cisco 7200, and Cisco 7500 Series
The clock source is obtained from the receive data stream of the line.
Cisco AS5300 Access Servers
The primary TDM clock source is from the T0 controller.
The secondary TDM clock source is from the T1 controller.Command Modes
Interface configuration
Command History
Usage Guidelines
Cisco 7000, Cisco 7200, and Cisco 7500 Series
A G.703-E1 interface, E1-G.703/G.704 serial port adapter, or a PA-E3 serial port adapter can clock its transmitted data from either its internal clock or from a clock recovered from the line's receive data stream.
Cisco AS5300 Access Servers
To use the clocking coming in from a T1 line, configure the clock source line primary command on the controller that has the most reliable clocking. Configure the clock source line secondary command on the controller that has the next best known clocking. With this configuration, the primary line clocking is backed up to the secondary line if the primary clocking shuts down.
Examples
Cisco 7000, Cisco 7200, and Cisco 7500 Series
The following example shows how to configure the G.703-E1 interface to clock its transmitted data from its internal clock:
Router(config)# interface serial 0/1Router(config-if)# clock source internalCisco AS5300 Access Servers
The following example shows how to configure the Cisco AS5300 to use serial interface 1/0 as the primary clocking source and the serial interface 2/0 as the secondary clocking source:
AS5300(config)# interface serial 1/0AS5300(config-if)# clock source line primaryAS5300(config-if)# exitAS5300(config)# interface serial 2/0AS5300(config-if)# clock source line secondaryThe following example shows how to specify the T3 interface to clock its transmitted data from its internal clock:
Router(config)# interface serial 1/0Router(config-if)# clock source internalclock source (J1 controller)
To configure the clock source for a J1 controller, use the clock source command in controller configuration mode. To restore the clock source to its default setting, use the no form of this command.
clock source {line | internal}
no clock source
Syntax Description
Defaults
Clock source is line for the J1 controller.
Command Modes
Controller configuration
Command History
Usage Guidelines
If multiple network modules are present in the router, then each J1 controller must be given a separate priority by configuration of the network-clock-select command. The controller having the highest priority will drive the internal clock.
Examples
The following example configures the clock source for line:
Router(config)# controller j1 3/0Router(config-controller)# clock source lineRelated Commands
clock source (MC3810)
To specify the clock source of a DS1 link on the Cisco MC3810 multiservice access concentrator, use the clock source command in controller configuration mode. To restore the clock source to its default setting, use the no form of this command.
clock source {line | internal | loop-timed}
no clock source
Syntax Description
Defaults
Line (when the MFT is installed)
Internal (when the DVM is installed)Command Modes
Controller configuration
Command History
Usage Guidelines
This command applies to Voice-over-Frame Relay, Voice-over-ATM, and Voice-over-HDLC on the Cisco MC3810.
Note
Examples
The following example configures the clock source for the MFT to internal, and the clock source for the DVM line on a Cisco MC3810 multiservice access concentrator:
Router(config)# controller T1 0Router(config-controller)# clock source internalRouter(config)# controller T1 1Router(config-controller)# clock source lineclock source (SONET controller)
To specify the clock source of a SONET controller, use the clock source command in controller configuration mode. To restore the clock source to its default setting, use the no form of this command.
clock source {internal | line | loop}
no clock source
Syntax Description
Defaults
Internal
Command Modes
Controller configuration
Command History
Examples
The following example shows how to specify line timing as the clock source on a SONET controller of an STM-1 card in physical slot number 2 on a Cisco AS5850:
Router(config)# controller sonet 2/0Router(config-controller)# clock source lineclock source (T1/E1 controller)
To set clocking for individual T1 or E1 links, use the clock source command in controller configuration mode. To return to the default, use the no form of this command.
clock source {line [primary | bits | independent] | internal [independent] | free-running}
no clock source
Syntax Description
Defaults
The default is line.
Command Modes
Controller configuration
Command History
Usage Guidelines
For a detailed discussion of clock sources on individual ports, refer to "Clock Sources on Digital T1/E1 Voice Ports" in the Voice Configuration Library at the following URL: http://www.cisco.com/en/US/products/ps6441/prod_configuration_guide09186a0080565f8a.html
Examples
The following example shows the router providing clock source to two controllers:
Router(config)# controller E1 1/0Router(config-controller)# framing crcRouter(config-controller)# linecoding hdb3Router(config-controller)# clock source internalRouter(config-controller)# ds0-group timeslots 1-15 type e&m-wink-start!Router(config)# controller E1 1/1Router(config-controller)# framing esfRouter(config-controller)# linecoding b8zsRouter(config-controller)# clock source internalRouter(config-controller)# ds0-group timeslots 1-15 type e&m-wink-startThe following example shows the digital voice hardware receiving clocking for the PLL from E1 1/0 and using this clock as a reference to clock E1 1/1. If controller E1 1/0 fails, the PLL internally generates the clock reference to drive E1 1/1.
Router(config)# controller E1 1/0Router(config-controller)# framing crcRouter(config-controller)# linecoding hdb3Router(config-controller)# clock source lineRouter(config-controller)# ds0-group timeslots 1-15 type e&m-wink-start!Router(config)# controller E1 1/1Router(config-controller)# framing crc4Router(config-controller)# linecoding hdb3Router(config-controller)# clock source internalRouter(config-controller)# ds0-group timeslots 1-15 type e&m-wink-startThe following example shows the router being configured to receive clocking from the BITS.
Router(config)# network-clock-participate slot 1Router(config)# network-clock-select 1 E1 1/1Router(config)# controller E1 1/1Router(config-controller)# clock source line bitsRelated Commands
controller
Configures a T1 or E1 controller and enters controller configuration mode.
clock source (T1/E1 interface)
To configure the clock source of a DS1 link, use the clock source command in interface configuration or ATM interface configuration mode. To restore the default line setting, use the no form of this command.
clock source {line | internal | loop-timed}
no clock source
Syntax Description
Defaults
line
Command Modes
Interface configuration
ATM interface configuration for the Cisco 2600 and Cisco 3600 series routersCommand History
Usage Guidelines
This command sets clocking for individual T1/E1 links.
Make sure that you specify the clock source correctly for each link, even if you are planning to specify that a certain link will provide clocking for all the links in an IMA group. Because links may be taken in and out of service, requiring that the system select another link for common clocking, any link in an IMA group may provide the common clock.
If the ATM interface is part of an IMA group, you can use the loop-timed keyword to specify that the clock source is the same as the IMA group clock source.
Examples
On a Cisco 2600 or Cisco 3600 series router, the following example specifies an internal clock source for the link:
Router(config)# interface atm 0/2Router(config-if)# clock source internalRelated Commands
clock source (T3/E3 controller)
To specify where the clock source is obtained for use by a T3 or E3 controller, use the clock source command in controller configuration mode. To restore the default clock source, use the no form of this command.
clock source {internal | line}
no clock source
Syntax Description
internal
Specifies that the internal clock source is used. This is the default for T3.
line
Specifies that the network clock source is used. This is the default for E3.
Defaults
The internal clock source is used for T3 controllers.
The line clock source is used for E3 controllers.Command Modes
Controller configuration
Command History
Usage Guidelines
If you do not specify the clock source command, the default clock source is used.
Configure the clock source line command if your telephone company or the remote data service unit provides the master clock of the T3 or E3 connection.
Configure the clock source internal command if your router provides the master clock of the T3 or E3 connection.
Note
Examples
The following example shows how to set the clock source to line:
Router(config)# controller t3 1/0Router(config-controller)# clock source lineRelated Commands
controller
Configures a T1 or E1 controller and enters controller configuration mode.
clock switchover
To specify the input lead state change that triggers the clock switching over from line to internal or from internal to line, use the clock switchover command in Data Circuit Terminating Equipment (DCE) split mode. To disable the command's effect, use the no form of this command.
clock switchover {rts | dtr | ll | rl} {off | on }
no clock switchover
Syntax Description
Command Default
The default state is on.
Command Modes
DCE split mode (off / on).
Command History
12.4(20)YA
This command was introduced.
12.4(22)T
This command is integrated into Cisco IOS Release 12.4(22)T.
Usage Guidelines
You can use the clock switchover command to switch the clock source over to internal clock. The switchover ensures continuity of the CEM channel when disruption in receiving the clock from the customer premises equipment (CPE) occurs. To specify the input lead state change that triggers the clock switching over from line to internal or from internal to line, use this option in DCE split mode.
Examples
The following example shows how the clock switchover <input_lead> <off | on > command is used to check the input lead state for the clock switchover feature:
Router(mode-prompt)# clock switchover dtr oncmt connect
To start the processes that perform the connection management (CMT) function and to allow the ring on one fiber to be started, use the cmt connect command in user EXEC or privileged EXEC mode.
cmt connect [fddi [port | slot/port] [phy-a | phy-b]]
Syntax Description
Command Modes
User EXEC
Privileged EXECCommand History
Usage Guidelines
In normal operation, the FDDI interface is operational once the interface is connected and configured. The cmt connect command allows the operator to start the processes that perform the CMT function.
The cmt connect command is not needed in the normal operation of FDDI; this command is used mainly in interoperability tests.
This command does not have a no form. To stop the CMT processes, use the cmt disconnect command.
Examples
The following examples demonstrate use of the cmt connect command for starting the CMT processes on the FDDI ring.
The following command starts all FDDI interfaces:
Router# cmt connect fddiThe following command starts both fibers on FDDI interface unit 0:
Router# cmt connect fddi 0The following command on the Cisco 7200 series or Cisco 7500 series starts both fibers on FDDI interface unit 0:
Router# cmt connect fddi 1/0The following command starts only Physical Sublayer A on FDDI interface unit 0:
Router# cmt connect fddi 0 phy-aRelated Commands
cmt disconnect
To stop the processes that perform the connection management (CMT) function and to allow the ring on one fiber to be stopped, use the cmt disconnect command in user EXEC or privileged EXEC mode.
cmt disconnect [fddi [port | slot/port] [phy-a | phy-b]]
Syntax Description
Command Modes
User EXEC
Privileged EXECCommand History
Usage Guidelines
In normal operation, the FDDI interface is operational once the interface is connected and configured, and is turned on using the no shutdown command in interface configuration mode. The cmt disconnect command allows the operator to stop the processes that perform the CMT function and allow the ring on one fiber to be stopped.
The cmt disconnect command is not needed in the normal operation of FDDI; this command is used mainly in interoperability tests.
This command does not have a no form. To start the CMT processes, use the cmt connect command.
Examples
The following examples demonstrate use of the cmt disconnect command for stopping the CMT processes on the FDDI ring.
The following command stops all FDDI interfaces:
Router# cmt disconnect fddiThe following command stops both fibers on FDDI interface unit 0:
Router# cmt disconnect fddi 0The following command on the Cisco 7200 series or Cisco 7500 series stops both fibers on FDDI interface unit 0:
Router# cmt disconnect fddi 1/0The following command stops only Physical Sublayer A on the FDDI interface unit 0. This command causes the FDDI media to go into a wrapped state so that the ring will be broken.
Router# cmt disconnect fddi 0 phy-aThe following command on the Cisco 7500 series stops only Physical Sublayer A on FDDI interface unit 0 in slot 1. This command causes the FDDI media to go into a wrapped state so that the ring will be broken.
Router# cmt disconnect fddi 1/0 phy-aRelated Commands
compress
To configure software compression for Link Access Procedure, Balanced (LAPB), PPP, and High-Level Data Link Control (HDLC) encapsulations, use the compress command in interface configuration mode. To disable compression, use the no form of this command.
compress {predictor | stac}
no compress {predictor | stac}
Cisco VIP2 Cards
compress {predictor | stac [distributed | software]}
no compress {predictor | stac [distributed | software]}
Cisco 7200 Series and Cisco 7500 Series
compress {predictor | stac [csa slot | software]}
no compress {predictor | stac [csa slot | software]}
PPP Encapsulation
compress [predictor | stac | mppc [ignore-pfc]]
no compress [predictor | stac | mppc [ignore-pfc]]
Syntax Description
Defaults
Compression is disabled.
Command Modes
Interface configuration
Command History
Note
Usage Guidelines
Point-to-Point Compression
Compression reduces the size of frames through lossless data compression. You can configure point-to-point software compression for all LAPB, PPP, and HDLC encapsulations. The compression algorithm used is a predictor algorithm (the RAND compression algorithm), which uses a compression dictionary to predict what the next character in the frame will be.
End-point devices must be configured to use the same compression method (predictor, Stacker or MPPC).
HDLC encapsulations supports the Stacker compression algorithm. PPP and LAPB encapsulations support both predictor and Stacker compression algorithms.
MPPC Compression
The compress command using the mppc and ignore-pfc options support compression between Cisco routers and access servers and Microsoft clients, such as Windows 95 and Windows NT. MPPC implements an LZ-based compression algorithm that uses a compression dictionary to compress PPP packets. The ignore-pfc keyword instructs the router to ignore the protocol field compression flag negotiated by LCP. For example, the standard protocol field value for IP is 0x0021 when compression is disabled and 0x21 when compression is enabled. When the ignore-pfc option is enabled, the router will continue to use the uncompressed value (0x0021). Using the ignore-pfc option is helpful for some asynchronous driver devices that use an uncompressed protocol field (0x0021), even though the pfc is negotiated between peers. If protocol rejects are displayed when the debug ppp negotiation command is enabled, setting the ignore-pfc option may remedy the problem.
HDLC Encapsulations
For HDLC encapsulations, you can specify a Stacker compression algorithm by using the stac keyword. PPP and LAPB encapsulations support both predictor and Stacker compression algorithms.
Public Data Network Connections
Compression requires that both ends of the serial link be configured to use compression. You should never enable compression for connections to a public data network.
Cisco 7200 and Cisco 7500 Series
Using CSA hardware compression on Cisco 7200 series routers and Cisco 7500 series routers removes the compression and decompression responsibilities from the VIP2 or the main processor installed in the router. By using the compress stac command, the router determines the fastest compression method available on the router.
On Cisco 7200 series routers and Cisco 7500 series routers, hardware compression on the compression service adapter (CSA) is supported for PPP links. When using hardware compression on Cisco 7200 series routers with multiple CSAs, you can optionally specify which CSA is used by the interface to perform compression. If no CSA is specified, the router determines which CSA is used. On Cisco 7500 series routers, the router uses the CSA on the same VIP2 as the interface.
System Performance
Caution
exceeds 40 percent. To display the CPU load, use the show process cpu EXEC command.
If the majority of your traffic is already compressed files, we recommend that you not use compression. If the files are already compressed, the additional processing time spent in attempting unsuccessfully to compress them again will slow system performance.
Table 5 provides general guidelines for deciding which compression type to select.
Software compression makes heavy demands on the router's processor. The maximum compressed serial line rate depends on the type of Cisco router that you are using and which compression algorithm you specify. Table 6 shows a summary of the compressed serial line rates for software compression. The maximums shown in Table 6 apply to the "combined" serial compressed load on the router. For example, a Cisco 4000 series router could handle four 64-kbps lines using Stacker compression or one 256-kbps line. These maximums also assume that there is very little processor load on the router aside from compression. Lower these numbers when the router is required to do other processor-intensive tasks.
Hardware compression can support a combined line rate of 16 Mbps.
Cisco recommends that you do not adjust the maximum transmission unit (MTU) for the serial interface and the LAPB maximum bits per frame (N1) parameter.
Note
compression algorithm is run over LAPB to ensure that everything is sent in order, with no missing
data and no duplicate data.
Note
Examples
The following example enables hardware compression and PPP encapsulation on serial interface 3/1/0.
Router(config)# interface serial 3/1/0Router(config-if)# encapsulate pppRouter(config-if)# compress stacThe following example enables predictor compression on serial interface 0 for a LAPB link:
Router(config)# interface serial 0Router(config-if)# encapsulation lapbRouter(config-if)# compress predictorRouter(config-if)# mtu 1509Router(config-if)# lapb n1 12072The following example enables Stacker compression on serial interface 0 for a LAPB link. This example does not set the MTU size and the maximum bits per frame (N1); we recommend that you do not change those LAPB parameters for Stacker compression:
Router(config)# interface serial 0Router(config-if)# encapsulation lapbRouter(config-if)# compress predictorThe following example configures BRI interface 0 to perform MPPC:
Router(config)# interface BRI0Router(config-if)# ip unnumbered ethernet0Router(config-if)# encapsulation pppRouter(config-if)# isdn spid1 5551234Router(config-if)# dialer map ip 172.21.71.74 5551234Router(config-if)# dialer-group 1Router(config-if)# compress mppcThe following example configures asynchronous interface 1 to implement MPPC and ignore the protocol field compression flag negotiated by LCP:
Router(config)# interface async1Router(config-if)# ip unnumbered ethernet0Router(config-if)# encapsulation pppRouter(config-if)# async default routingRouter(config-if)# async dynamic routingRouter(config-if)# async mode interactiveRouter(config-if)# peer default ip address 172.21.71.74Router(config-if)# compress mppc ignore-pfcRelated Commands
compress mppc
To configure compression using the Microsoft Point-to-Point Compression (MPPC) algorithm on your data compression Advanced Interface Module (AIM) for the Cisco 2600 series router, use the compress mppc command in interface configuration mode. To disable MPPC compression, use the no form of this command.
compress mppc
no compress mppc
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
The MPPC compression algorithm is used to exchange compressed information with a Microsoft NT remote access server.
When configuring PPP on a serial interface, you can use hardware compression on the data compression AIM daughter card for MPPC if one is installed; otherwise you can use software compression.
Examples
The following example shows how to configure the data compression AIM daughtercard for MPPC:
Router(config-if)# encapsulate pppRouter(config-if)# compress mppcRelated Commands
compress stac caim
To specify the hardware compression, use the compress stac caim command in interface configuration mode. To disable compression, use the no form of this command.
compress stac caim interface-number
no compress stac caim interface-number
Syntax Description
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Hardware Compression
If the router contains a data compression Advanced Interface Module (CAIM), compression is performed in the CAIM hardware.
Using hardware compression in the AIM frees the main processor of the router for other tasks. You can also configure the router to use the Compression Port Module to perform compression by using the distributed option or to use the router's main processor by using the software option. If the Compression Port Module compression is performed in the main processor of the router.
Software Compression
If the CAIM is not available, compression is performed in the main processor of the router.
When compression is performed by the software installed in the router's main memory, system performance might be affected significantly. It is recommended that you disable compression in the main processor if the router CPU load exceeds 40 percent. To display the CPU load, use the show process cpu command in EXEC mode.
Examples
The following example specifies that hardware compression should be activated for CAIM interface 0:
Router(config-if)# encapsulation pppRouter(config-if)# compress stac caim 0Related Commands
connect (module)
To create a connection between two Gigabit Ethernet (GE) enhanced network modules (ENMs) or between the GE port on an installed small-form-factor-pluggable (SFP) module and a GE ENM, or between the GE port on a switch module (SM) and another SM GE port, on a Cisco 2900 series (Cisco 2901 ISRs do not support the HIMI backplane feature.), 3800 series, or 3900 series Integrated Services Router (ISR), use the connect command in global configuration mode. To deactivate a connection between two GE modules on a Cisco 3800 series router, use the no form of this command.
connect connection-name module module1 channel-id1 module module2 channel-id2
no connect connection-name
To create a dedicated connection between two GE ENMs, or between the GE port on an SFP module and a GE ENM, or between the GE port on a SM and another SM GE port, for the purpose of sending data on a specified VLAN on a Cisco 3900 series or 2900 series (Cisco 2901 ISRs do not support vlan connect in configuring the HIMI backplane feature.), use the connect command in global configuration mode with the vlan vlan-id syntax. To deactivate a connection between two GE interfaces on a Cisco 3900 series router, 2900 series (Cisco 2901 ISRs do not support vlan connect in configuring the HIMI backplane feature.), use the no form of this command.
connect connection-name module module1 vlan vlan-id module module2
no connect connection-name
Syntax Description
Command Default
There is no connection between GE ENMs.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
To create a connection between two GE modules on a Cisco 2900 (Cisco 2901 ISRs do not support the HIMI backplane feature.), 3800, and 3900 series routers using the High-Speed Intrachassis Module Interconnect (HIMI) feature, use the connect connection-name module module1 channel-id1 module module2 channel-id2 command in global configuration mode:
Connections can be only established as follows:
•
•
•
Note
Note
To create a connection between two GE SMs, to send data on a specified VLAN, on a VLAN on a Cisco 2900 (Cisco 2901 ISRs do not support the HIMI backplane feature.), and 3900, use the connect command with the with the vlan vlan-id syntax.
If the connect command is successfully executed, the router enters connection configuration mode, which is designated by the "config-module-conn" prompt. Once the router is in connection configuration mode, the commands shown in Table 7 can be issued.
To establish a connection, after entering connection configuration mode, issue the exit command to return to configuration mode. The connection will be established after you leave connection configuration mode.
Examples
The following example illustrates the creation of a connection between the onboard port GigabitEthernet0/0 and port GigabitEthernet4/0, which resides in ENM slot 4:
Router(config)# connect connection1 module GigabitEthernet0/0 0 module GigabitEthernet4/0 0Router(config-module-conn)# exitThe following example shows the creation of a VLAN connection which is named VLAN 10 and a second VLAN connection which is named VLAN 5.
Router(config)# connect connection1 module gi2/0 vlan 10 module gi3/0Router(config-module-conn)# connect connection2 module gi3/0 vlan 5 module gi4/0Router(config-module-conn)# exitRelated Commands
control-lead sampling-rate
To configure the sampling rate of input control leads, use the control-lead sampling-rate command in CEM configuration mode.
control-lead sampling-rate rate
Syntax Description
Command Default
The input control lead sampling rate defaults to 0 (no sampling).
Command Modes
CEM configuration
Command History
Usage Guidelines
This command applies only to serial channels. This command does not have a no form; to disable control-lead sampling, set the rate argument to 0.
Examples
The following example shows how to configure the ingress control-lead sampling rate to 20 samples per second on a serial CEM port.
Router(config-cem)# control-lead sampling-rate 20
Related Commands
control-lead state
To specify the state of an output control lead, use the control-lead state command in CEM configuration mode. The choice of output lead depends on whether the port is DCE or DTE.
control-lead state {active | fail} output-lead {on | off | follow} [{local | remote} follow-lead]
Syntax Description
Command Default
The default Active template that is activated depends on whether the port is DCE or DTE. The default Fail template deactivates all signals. Table 8 shows the various control-lead default states.
Table 8 Control-Lead Default States
1
CTS
RTS
On
Off
2
DSR
DTR
On
Off
3
DCD
—
On
Off
4
—
LL
Off
—
5
TM
—
On
Off
6
RI
RL
Off
Off
Command Modes
CEM configuration
Command History
Usage Guidelines
The state of each output control lead may be specified to assume a constant level (on or off) or to change on the basis of the state of any input control lead, either at the local data port or at the remote data port.
This command applies only to serial ports. This command does not have a no form; to disable the control lead, specify the off keyword.
Examples
The following example shows how to specify the state of an output control lead.
Router(config-cem)# control-lead state active cts on
Related Commands
cem
Enters circuit emulation configuration mode.
control-lead sampling-rate
Configures the sampling rate of input control leads.
show cem
Displays CEM channel statistics.
controller
To configure a T1, E1, or J1 controller and enter controller configuration mode, use the controller command in global configuration mode.
Cisco 2600 and 3600 Series Routers
controller {t1 | e1 | j1} slot/port
Cisco 7200 Series and Cisco 7500 Series Routers
controller {t1 | e1} slot/port
Cisco AS5300 Access Servers
controller {t1 | e1} number
Cisco AS5800 Access Servers
controller t1 dial-shelf/slot/t3-port:t1-num
Syntax Description
Defaults
No T1, E1, or J1 controller is configured.
Command Modes
Global configuration
Command History
Usage Guidelines
T1 or E1 Fractional Data Lines
This command is used in configurations where the router or access server is intended to communicate with a T1 or E1 fractional data line. Additional parameters for the T1 or E1 line must be configured for the controller before the T1 or E1 circuits can be configured by means of the interface global configuration command.
To view the status of the controllers use the show controllers command.
Examples
Cisco 7500 Series Router As a T1 Controller
The following example configures the MIP in slot 4, port 0 of a Cisco 7500 series router as a T1 controller:
Router(config)# controller t1 4/0Router(config-controller)#Cisco AS5800 Access Server with Dial Shelf
The following example configures the T1 controller in shelf 1, slot 0, port 0:
Router(config)# controller t1 1/0/0:1Router(config-controller)#Cisco 3660 As a J1 Controller
The following example configures the Cisco IOS interface card in slot 3, port 0 of a Cisco 3660 as a J1 controller:
Router(config)# controller j1 3/0Router(config-controller)#Related Commands
controller dsl
To configure the digital subscriber line (DSL) controller and enter controller configuration mode, use the controller dsl command in global configuration mode. This command does not have a no form.
controller dsl slot/port
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
Usage Guidelines
This command is used to enter controller configuration mode for the controller in the specified slot and port. If the controller is present, it is automatically set to a default set of values, including customer premises equipment (CPE) mode and annex A.
The central office (CO) and CPE sides of the link must be configured the same in order for a connection to be made. This command is available only when the WIC-1SHDSL-V2 is installed.
Examples
The following example shows how to enter DSL controller configuration mode on the controller in slot 1 and port 0:
Router(config)# controller dsl 1/0Router(config-controller)#Related Commands
controller dwdm
To configure a Dense Wavelength-Division Multiplexing (DWDM) controller, use the controller dwdm command in global configuration mode. This command does not have a no form.
controller dwdm slot/port
Syntax Description
slot/port
Number of the chassis slot that contains the interface, where:
•
•
Command Default
No default behavior or values
Command Modes
Global configuration (config)
Command History
Examples
The following example shows how to configure a DWDM controller in slot 3:
Router(config)# controller dwdm 3/1Related Commands
controller e3
To configure an E3 controller and enter controller configuration mode, use the controller e3 command in global configuration mode.
controller e3 slot/port
Syntax Description
slot/port
Number of the slot and port being configured. Refer to the appropriate hardware manual for slot and port information. The slash mark is required.
Defaults
No E3 controller is configured.
Command Modes
Global configuration
Command History
Examples
The following example shows the E3 controller configured in slot 0, port 0:
Router(config)# controller e3 0/0Router(config-controller)#Related Commands
controller sonet
To configure a SONET controller and enter controller configuration mode, use the controller sonet command in global configuration mode.
controller sonet slot/port
Syntax Description
Defaults
port: 0
Command Modes
Global configuration
Command History
12.0(14)S
This command was introduced.
12.2(15)T
This command was integrated into Cisco IOS Release 12.2(15)T.
Usage Guidelines
This command does not have a no form because the SONET controller is created automatically when the STM-1 trunk card is detected by the Cisco AS5850. Use this command to specify which slot number the STM-1 card is plugged into and to configure different attributes under controller configuration mode.
Examples
The following example shows how to specify that the SONET controller is in slot number 2:
Router(config)# controller sonet 2/0Router(config-controller)#Related Commands
controller t3
To configure the Channelized T3 Interface Processor (CT3IP) in Cisco 7500 series routers or the CT3 feature board in Cisco AS5800 access servers, use the controller t3 command in global configuration mode. To delete the defined controller, use the no form of this command.
Cisco 7500 Series
controller t3 slot/port-adapter/port
no controller t3 slot/port-adapter/port
Cisco AS5800 Access Server
controller t3 dial-shelf/slot/t3-port
no controller t3 dial-shelf/slot/t3-port
Syntax Description
Defaults
Cisco 7500 Series
No T3 controller is configured.
Cisco AS5800 Access Server
No default behavior or values.
Command Modes
Global configuration
Command History
11.3
This command was introduced.
12.0(3)T
This command was implemented on the Cisco AS5800 access server.
Usage Guidelines
This command is used to configure the CT3IP and the 28 T1 channels. After the T1 channels are configured, continue to configure each T1 channel as a serial interface by using the interface serial global configuration command
Examples
Cisco 7500 Series
The following example configures the CT3IP in slot 3:
Router(config)# controller t3 3/0/0Cisco AS5800 Access Server
The following example configures the T3 controller in shelf 3, slot 0, port 0 and T1 time slot 1:
Router(config)# controller t3 3/0/0Related Commands
copy flash lex
To download an executable image from Flash memory on the core router to a LAN Extender, use the copy flash lex command in privileged EXEC mode.
copy flash lex number
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
If you attempt to download a version of the software older than what is currently running on the LAN Extender, a warning message is displayed.
This command does not have a no form.
Examples
The following example copies the executable image namexx to LAN Extender interface 0:
Router# copy flash lex 0Name of file to copy? namexxAddress of remote host [255.255.255.255] <cr>writing namexx !!!!!!!!!!!!!!!!!!!!!!!!!copy completeRelated Commands
copy tftp lex
Downloads an executable image from a TFTP server to a LAN Extender.
copy tftp lex
To download an executable image from a TFTP server to the LAN Extender, use the copy tftp lex command privileged EXEC mode.
copy tftp lex number
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
If you attempt to download a version of the software older than what is currently running on the LAN Extender, a warning message is displayed.
This command does not have a not form.
Examples
The following example copies the file namexx from the TFTP server:
Router# copy tftp lex 0Address or name of remote host (255.255.255.255]? 10.108.1.111Name of file to copy? namexxOK to overwrite software version 1.0 with 1.1 ?[confirm] YLoading namexx from 10.108.13.111!!!!!!!!!!!!!!!!!!!!!!!!![OK - 127825/131072 bytes]Successful download to LAN Extendercrc
To set the length of the cyclic redundancy check (CRC), use the crc command in interface configuration mode. To set the CRC length to the default value, use the no form of this command.
crc size-in-bits
no crc
Syntax Description
Defaults
Cisco 7500 Series Router
16 bits
Cisco 10000 Series Router
32 bits
Command Modes
Interface configuration
Command History
Usage Guidelines
All interfaces use a 16-bit CRC by default, but also support a 32-bit CRC. CRC is an error-checking technique that uses a calculated numeric value to detect errors in transmitted data. The designators 16 and 32 indicate the length (in bits) of the frame check sequence (FCS). A CRC of 32 bits provides more powerful error detection, but adds overhead. Both the sender and receiver must use the same setting.
CRC-16, the most widely used CRC rate throughout the United States and Europe, is used extensively with WANs. CRC-32 is specified by IEEE 802 and as an option by some point-to-point transmission standards. It is often used on Switched Multimegabit Data Service (SMDS) networks and LANs.
Examples
The following example enables the 32-bit CRC on serial interface 3/0:
Router(config)# interface serial 3/0Router(config-if)# crc 32crc bits 5
To enable generation of CRC5 (per ITU Recommendation G.704 and G.703) to improve data integrity, use the crc bits 5 command in interface configuration mode. To disable this function, use the no form of this command.
crc bits 5
no crc bits 5
Syntax Description
This command has no arguments or keywords.
Defaults
CRC5 checking is disabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command is available for the JT2 6.3-MHz serial port adapter (PA-2JT2) on the second-generation Versatile Interface Processor (VIP2), in Cisco 7500 series routers, and in Cisco 7000 series routers with the Cisco 7000 series Route Switch Processor (RSP7000) and the Cisco 7000 series Chassis Interface (RSP7000CI).
This command is useful for checking data integrity while operating in framed mode. CRC5 provides additional protection for a frame alignment signal under noisy conditions. For data transmission at JT2 (6.312 Mbps), the G.704 standard suggests 5 bits CRC. Refer to ITU Recommendation G.704 for a definition of CRC5.
You can also use the crc command to set the CRC size for the High-Level Data Link Control (HDLC) controllers.
Examples
The following example enables CRC5 generation on the PA-2JT2 port adapter and also sets the CRC size to 32 bits:
Router(config)# interface serial 0/0Router(config-if)# crc 32Router(config-if)# crc bits 5Related Commands
crc4
To enable generation of CRC4 (per ITU Recommendation G.704 and G.703) to improve data integrity, use the crc4 command in interface configuration mode. To disable this function, use the no form of this command.
crc4
no crc4
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
This command applies to the Cisco 7200 series, Cisco 7000 series, and Cisco 7500 series routers. This command is supported on the Fast Serial Interface Processor (FSIP) and the E1-G.703/G.704 serial port adapter.
This command is useful for checking data integrity while operating in framed mode. CRC4 provides additional protection for a frame alignment signal under noisy conditions. For data transmission at E1 (2.048 Mbps), the G.704 standard suggests 4 bits CRC. Refer to CCITT Recommendation G.704 for a definition of CRC4.
You can also use the crc command to set the CRC size for the High-Level Data Link Control (HDLC) controllers.
Examples
The following example enables CRC4 generation on the E1-G.703/G.704 serial port adapter and also sets the CRC size to 32 bits:
Router(config)# interface serial 0/0Router(config-if)# crc 32Router(config-if)# crc4Related Commands
crc-threshold
To define a severely errored second (SES) by specifying the number of cyclic redundancy check (CRC) errors that occur in one second, use the crc-threshold command in controller configuration mode. To return to the default value, use the no form of this command.
crc-threshold value
no crc-threshold
Syntax Description
value
Number of CRC errors in one second that results in the second being declared a severely errored second (SES). Range is from 0 to 3000. Default is 320.
Command Default
A default SES is defined by a value of 320 CRC errors per second.
Command Modes
Controller configuration
Command History
Usage Guidelines
On a T1 port, this command applies only if extended super frame (ESF) framing is used because the super frame (SF) (also known as D4) frame structure does not include any CRC protection.
This command does not apply to an E1 port.
Examples
The following example shows how to set the CRC threshold at 512 CRC errors in one second.
Router(config-controller)# crc-threshold 512ctunnel mode
To transport IPv4 and IPv6 packets over Connectionless Network Service (CLNS) tunnel (CTunnel), use the ctunnel mode command in interface configuration mode. To return the ctunnel to the default cisco mode, use the no form of this command.
ctunnel mode [gre | cisco]
no ctunnel mode
Syntax Description
gre
(Optional) Sets the ctunnel mode to Generic Routing Encapsulation (GRE) for transporting IPv6 packets over the CLNS network.
cisco
(Optional) Returns the ctunnel mode to the default cisco.
Command Default
Cisco encapsulation
Command Modes
Interface configuration
Command History
Usage Guidelines
GRE tunneling of IPv4 and IPv6 packets through CLNS-only networks enables Cisco ctunnels to interoperate with networking equipment from other vendors. This feature provides compliance with RFC 3147, Generic Routing Encapsulation over CLNS Networks, which should allow interoperation between Cisco equipment and that of other vendors. in which the same standard is implemented.
RFC 3147 specifies the use of GRE when tunneling packets. The implementation of this feature does not include support for GRE header fields such as those used to specify checksums, keys, or sequencing. Any packets received which specify the use of these features will be dropped.
The default ctunnel mode continues to use the standard Cisco encapsulation. Both ends of the tunnel must be configured with the same mode for it to work. If you want to tunnel ipv6 packets you must use the new gre mode.
Examples
The following example configures a CTunnel from one router to another and shows the CTunnel destination set to 49.0001.1111.1111.1111.00. The ctunnel mode is set to gre to transport IPv6 packets.
interface ctunnel 301ipv6 address 2001:0DB8:1111:2222::2/64ctunnel destination 49.0001.1111.1111.1111.00ctunnel mode greRelated Commands
cut-through
To configure the interfaces on the PA-12E/2FE port adapter to use cut-through switching technology between interfaces within the same bridge group, use the cut-through command in interface configuration mode. To return each interface to store-and-forward switching, use the no form of this command.
cut-through [receive | transmit]
no cut-through
Syntax Description
receive
(Optional) Selects cut-through switching technology on received data.
transmit
(Optional) Selects cut-through switching technology on transmitted data.
Defaults
Store-and-forward switching technology (that is, no cut-through)
Command Modes
Interface configuration
Command History
Usage Guidelines
Cut-through mode allows switched packets to be transmitted after 64 bytes are received. The transmission of the packets can start before the end of the packet arrives. This reduces the time spent in the switch, but allows packets to be transmitted with bad cyclical redundancy checks (CRCs), because the transmission is initiated before the CRC is received or checked. Store-and-forward mode waits for the entire packet to be received before that packet is forwarded, but will check the CRC before starting transmission.
The PA-12E/2FE port adapter offloads Layer 2 switching from the host CPU by using store-and-forward or cut-through switching technology between interfaces within the same VLAN on the PA-12E/2FE port adapter. The PA-12E/2FE port adapter supports up to four VLANs (bridge groups).
Examples
The following example configures interface 3/0 for cut-through switching:
Router(config)# interface fastethernet 3/0Router(config-if)# bridge-group 10Router(config-if)# cut-throughRouter(config-if)# no shutdownRouter(config-if)# exit
