Cisco IOS Interface and Hardware Component Command Reference, Release 12.3 T
Interface and Hardware Component Commands: D through H

Table Of Contents

data-protection

data-strobe

dce-terminal-timing enable

default (CEM)

dejitter-buffer

delay (interface)

description (controller)

dot1q tunneling ethertype

down-when-looped

ds0-group (J1 controller)

dsl-mode shdsl symmetric annex

dsu bandwidth

dsu mode

dte-invert-txc

duplex

e2-clockrate

early-token-release

encapsulation

end (satellite initial configuration)

exit (satellite initial configuration)

error throttling

fddi burst-count

fddi c-min

fddi cmt-signal-bits

fddi duplicate-address-check

fddi encapsulate

fddi frames-per-token

fddi smt-frames

fddi tb-min

fddi tl-min-time

fddi token-rotation-time

fddi t-out

fddi valid-transmission-time

fdl

framing

framing (CEM)

framing (E3 controller)

framing (SONET)

framing (T1/E1 controller)

framing (T3 controller)

framing (T3/E3 interface)

full-duplex

half-duplex

half-duplex controlled-carrier

half-duplex timer

hold-queue

hssi external-loop-request

hssi internal-clock

hub

hw-module main-cpu qa error-recovery

hw-module sec-cpu reset

hw-module slot

hw-module slot image


data-protection

To enable data protection for a circuit emulation (CEM) channel, use the data-protection command in CEM configuration mode. To disable data protection, use the no form of this command.

data-protection

no data-protection

Syntax Description

This command has no arguments or keywords.

Defaults

Data protection is disabled.

Command Modes

CEM configuration

Command History

Release
Modification

12.3(7)T

This command was introduced.


Examples

The following example demonstrates how to enable data protection.

Router(config-cem)# data-protection

Related Commands

Command
Description

cem

Enters circuit emulation configuration mode.

clear cem

Clears CEM channel statistics.

show cem

Displays CEM channel statistics.


data-strobe

To specify an input control lead to be monitored as an indicator of valid data, use the data-strobe command in CEM configuration mode. To disable the monitoring of an input control lead, use the no form of this command.

data-strobe input-lead {on | off}

no data-strobe

Syntax Description

input-lead

Specifies the input lead. The choice of leads depends on whether the port is DCE or DTE.

on

Enables packet creation when the lead is asserted.

off

Enables packet creation when the lead is deactivated.


Defaults

No input control lead is monitored.

Command Modes

CEM configuration

Command History

Release
Modification

12.3(7)T

This command was introduced.


Usage Guidelines

Any input control signal on a serial data port may be configured as a "data strobe" to indicate to the NM-CEM-4SER network module whether ingress data on the port should be encapsulated for transmission or ignored. If the data strobe command is specified with the on keyword, data packets are created and sent when the input lead is asserted. If the data strobe is off (either intentionally, or as a result of the failure of the customer premises equipment [CPE]), no data packets are created, and this results in preservation of bandwidth in the IP network.

This command applies only to serial ports.

Examples

The following example demonstrates how to specify that packets are to be created and sent to the far end only when the DTR input control lead is asserted.

Router(config-cem)# data-strobe dtr on

Related Commands

Command
Description

cem

Enters circuit emulation configuration mode.

clear cem

Clears CEM channel statistics.

control-lead sampling rate

Configures the sampling rate of input control leads.

control-lead state

Specifies the state of an output control lead.

show cem

Displays CEM channel statistics.


dce-terminal-timing enable

To prevent phase shifting of the data with respect to the clock when running the line at high speeds and long distances, use the dce-terminal-timing enable command in interface configuration mode. If serial clock transmit external (SCTE) terminal timing is not available from the DTE, use the no form of this command; the DCE will use its own clock instead of SCTE from the DTE.

dce-terminal-timing enable

no dce-terminal-timing enable

Syntax Description

This command has no arguments or keywords.

Defaults

The DCE uses its own clock.

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

On the Cisco 4000 router, you can specify the serial Network Interface Module timing signal configuration. When the board is operating as a DCE and the DTE provides terminal timing (SCTE or TT), the dce-terminal-timing enable command causes the DCE to use SCTE from the DTE.

Examples

The following example shows how to prevent phase shifting of the data with respect to the clock:

Router(config)# interface serial 0
Router(config-if)# dce-terminal-timing enable

default (CEM)

To reset channel options to their default values, use the default command in CEM configuration mode.

default {data-protection | dejitter-buffer | idle-pattern | ip dscp | ip tos | ip precedence | payload-compression | payload-size | signaling}

Syntax Description

data-protection

Resets data protection to its default value.

dejitter-buffer

Resets the dejitter buffer to its default value.

idle-pattern

Resets the idle pattern to its default value.

ip dscp

Resets the IP differentiated services code point (DSCP) field to its default value.

ip tos

Resets the IP type of service (ToS) field to its default value.

ip precedence

Resets the IP precedence field to its default value.

payload-compression

Resets payload compression to its default value.

payload-size

Resets payload size to its default value.

signaling

Resets signaling to its default value.


Defaults

The CEM channel options are set at their configured values.

Command Modes

CEM configuration

Command History

Release
Modification

12.3(7)T

This command was introduced for CEM configuration mode.


Examples

The following example demonstrates how to reset CEM channel data protection to its default value.

Router(config-cem)# default data-protection

Related Commands

Command
Description

cem

Enters circuit emulation configuration mode.

clear cem

Clears CEM channel statistics.

data-protection

Enables data protection.

dejitter-buffer

Configures the dejitter buffer size.

idle-pattern

Defines the idle pattern that the channel transmits when it goes down.

payload-compression

Enables payload compression.

payload-size

Configures the payload size.

show cem

Displays CEM channel statistics.

signaling

Enables CAS signaling.


dejitter-buffer

To configure the size of the dejitter buffer, use the dejitter-buffer command in CEM configuration mode. To restore the dejitter buffer to its default size, use the no form of this command.

dejitter-buffer size

no dejitter-buffer

Syntax Description

size

Size, in milliseconds, of the dejitter buffer. The range is from 5 to 500. The default is 60.


Defaults

The dejitter buffer defaults to 60 milliseconds.

Command Modes

CEM configuration

Command History

Release
Modification

12.3(7)T

This command was introduced.


Examples

The following example shows how to set the dejitter buffer to 200 milliseconds.

Router(config-cem)# dejitter-buffer 200

Related Commands

Command
Description

cem

Enters circuit emulation configuration mode.

clear cem

Clears CEM channel statistics.

show cem

Displays CEM channel statistics.


delay (interface)

To set a delay value for an interface, use the delay command in interface configuration mode. To restore the default delay value, use the no form of this command.

delay tens-of-microseconds

no delay

Syntax Description

tens-of-microseconds

Integer that specifies the delay in tens of microseconds for an interface or network segment. To see the default delay, use the show interfaces command.


Defaults

Default delay values may be displayed with the show interfaces EXEC command.

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.


Examples

The following example shows how to set a delay of 30,000 microseconds on serial interface 3:

Router(config)# interface serial 3
Router(config-if)# delay 3000

Related Commands

Command
Description

show interfaces

Displays the statistical information specific to a serial interface.


description (controller)

To add a description to an E1 or T1 controller or the Channelized T3 Interface Processor (CT3IP) in Cisco 7500 series routers, use the description command in controller configuration mode. To remove the description, use the no form of this command.

description string

no description

Syntax Description

string

Comment or description (up to 80 characters) to help you remember what is attached to an interface.


Defaults

No description is added.

Command Modes

Controller configuration

Command History

Release
Modification

10.3

This command was introduced.

11.3

This command was modified to include the CT3IP controller.


Usage Guidelines

The description command is meant solely as a comment to be put in the configuration to help you remember what certain controllers are used for. The description affects the CT3IP and Multichannel Interface Processor (MIP) interfaces only and appears in the output of the show controller e1, show controller t1, show controller t3, and show running-config EXEC commands.

Examples

The following example shows how to add a description for a 3174 controller:

Router(config)# controller t1
Router(config-controller)# description 3174 Controller for test lab

Related Commands

Command
Description

show controllers e1

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

show controllers t1

Displays information about the T1 links.

show controllers t3

Displays information about the CT3IP on Cisco 7500 series routers.


dot1q tunneling ethertype

To define the Ethertype field type used by peer devices when implementing Q-in-Q VLAN tagging, use the dot1q tunneling ethertype command in interface configuration mode. To remove the VLAN tag Ethertype, use the no form of this command.

dot1q tunneling ethertype ethertype

no dot1q tunneling ethertype ethertype

Syntax Description

ethertype

Type of Ethertype field. Valid values are either 0x8100 or 0x9100. Default is 0x8100.


Defaults

The Ethertype field used by peer devices when implementing Q-in-Q VLAN tagging is 0x8100.

Command Modes

Interface configuration

Command History

Release
Modification

12.3(7)T

This command was introduced.


Usage Guidelines

Use the dot1q tunneling ethertype command if the peer switching devices are using an Ethertype field value of 0x9100. All Cisco switching devices use the default Ethertype field value of 0x8100.

This command is used with the IEEE 802.1Q-in-Q VLAN Tag Termination feature in which double VLAN tagging is configured using the encapsulation dot1q command. 802.1q double tagging allows a service provider to use a single VLAN to support customers who have multiple VLANs.

Examples

The following example shows how to configure an Ethertype field as 0x9100:

Router(config)# interface gigabitethernet 1/0/0
Router(config-if)# dot1q tunneling ethertype 0x9100

Related Commands

Command
Description

encapsulation dot1q

Enables 802.1q encapsulation of traffic on a specified subinterface or range of subinterfaces.

interface

Configures an interface and enters interface configuration mode.


down-when-looped

To configure an interface to inform the system that it is down when loopback is detected, use the down-when-looped command in interface configuration mode.

down-when-looped

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

This command is valid for High-Level Data Link Control (HDLC) or PPP encapsulation on serial and High-Speed Serial Interface (HSSI) interfaces.

This command does not have a no form.

Backup Interfaces

When an interface has a backup interface configured, it is often desirable that the backup interface be enabled when the primary interface is either down or in loopback. By default, the backup is enabled only if the primary interface is down. By using the down-when-looped command, the backup interface will also be enabled if the primary interface is in loopback.

Testing an Interface with the Loopback Command

If testing an interface with the loopback command, or by placing the DCE into loopback, the down-when-looped command should not be configured; otherwise, packets will not be transmitted out the interface that is being tested.

Examples

The following example shows how to configure interface serial 0 for HDLC encapsulation. The interface is then configured to let the system know that it is down when in loopback mode.

Router(config)# interface serial0
Router(config-if)# encapsulation hdlc
Router(config-if)# down-when-looped

Related Commands

Command
Description

backup interface

Configures an interface as a secondary or dial backup interface.

loopback (E3 controller)

Diagnoses equipment malfunctions between an interface and a device.


ds0-group (J1 controller)

To configure channelized J1 time slots, use the ds0-group command in controller configuration mode. To remove the DS0 group, use the no form of this command.

ds0-group ds0-group-no timeslots timeslot-list type external-signaling

no ds0-group ds0-group-no timeslots timeslot-list type external-signaling

Syntax Description

ds0-group-no

Specifies the DS0 group number.

timeslots timeslot-list

Specifies the DS0 time slot range of values from 1 to 31 for J1 interfaces. Time slot 16 is reserved for signaling.

type external-signaling

Specifies that the signaling traffic comes from an outside source. The signaling method selection for type depends on the connection that you are making.


Defaults

No DS0 group is defined.

Command Modes

Controller configuration

Command History

Release
Modification

11.2

This command was originally the cas-group command.

12.0(1)T

The cas-group command was introduced for the Cisco 3600 series.

12.0(5)XE

The command was renamed ds0-group on the Cisco AS5300 and on the Cisco 2600 and Cisco 3600 series.

12.0(7)T

The command was integrated into the Cisco IOS Release 12.0(7)T.

12.2(8)T

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


Usage Guidelines

The ds0-group command replaces the existing cas-group command. Making the command generic allows flexibility and scalability. It is not restricted to channel associated signaling (CAS) or channel bundling.

The ds0-group command automatically creates a logical voice port that is numbered as follows on Cisco 2600 and Cisco 3600 series routers: slot/port:ds0-group-no. Although only one voice port is created for each group, applicable calls are routed to any channel in the group.

Examples

The following example is sample output from the show controllers j1 command on the Cisco 3660 series after channelized J1 time slots have been configured:

Router(config-controller)# ds0-group 1 timeslots 1-15,17-31 type e&m-wink-start 
Router(config-controller)# end
Router# show controllers j1

*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(1), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(2), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(3), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(4), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(5), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(6), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(7), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(8), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(9), cp
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(10), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(11), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(12), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(13), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(14), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(15), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(17), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(18), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(19), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(20), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(21), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(22), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(23), p
*Mar  1 03:12:26.259: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(24), p
*Mar  1 03:12:26.263: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(25), p
*Mar  1 03:12:26.263: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(26), p
*Mar  1 03:12:26.263: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(27), p
*Mar  1 03:12:26.263: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(28), p
*Mar  1 03:12:26.263: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(29), p
*Mar  1 03:12:26.263: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(30), p
*Mar  1 03:12:26.263: %LINK-3-UPDOWN: Interface recEive and transMit3/0:0(31), p

Related Commands

Command
Description

ds0 busyout

Busyouts one or more signal level 0s (DS0s).


dsl-mode shdsl symmetric annex

To specify the operating mode of the digital subscriber line (DSL) controller, use the dsl-mode shdsl symmetric annex command in controller configuration mode. To return the DSL to the default Annex A, use the no form of this command.

dsl-mode shdsl symmetric annex mode

Syntax Description

mode

Sets the DSL operating mode. The valid values are:

a: Supports Annex A of the G.991.2 standard for North America. This is the default.

b: Supports Annex B of the G.991.2 standard for Europe.

a-b: Supports Annex A or B. For CPE mode only. Not supported in CO mode. Selected when the line trains.

a-b-anfp: Supports Annex A or B-ANFP. For CPE mode only. Not supported in CO mode. Selected when the line trains.

b-anfp: Supports Annex B-ANFP.


Defaults

The annex defaults to A for North America.

Command Modes

Controller configuration

Command History

Release
Modification

12.3(4)XD

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

12.3(4)XG

This command was integrated into the Cisco IOS Release 12.3(4)XG on the Cisco 1700 series routers.

12.3(7)T

This command was integrated into Cisco IOS Release 12.3(7)T on Cisco 2600 series, Cisco 3631, and Cisco 3700 series routers.

12.3(11)T

Support for the following additional annex parameters was integrated into Cisco IOS Release 12.3(11)T to support Cisco 1700, Cisco 1800, Cisco 2600, Cisco 2800, Cisco 3700, and Cisco 3800 series routers:

b

a-b

a-b-anfp

b-anfp


Usage Guidelines

This command is used to configure the DSL controller interface to operate in a specified DSL mode and to set regional operating parameters. The shdsl keyword is used to set the mode to SHDSL and configures multirate, high-speed DSL per ITU G.991.2. The symmetric keyword configures the controller to symmetric mode. The annex keyword configures the controller to use regional operating parameters. The regional operating parameters default to North America.

Examples

The following example displays the use of the controller dsl 0/0 command to configure the controller in the router configured on the central office (CO) side. Use the dsl-mode shdsl symmetric annex b command to configure the controller for multirate, high-speed DSL with symmetric mode for European operating parameters.

Router# configure terminal 

Router(config)# controller dsl 0/0
Router(config-controller)# line-term co
Router(config-controller)# dsl-mode shdsl symmetric annex b
Router(config-controller)# mode atm
Router(config-controller)#
00:22:07: %CONTROLLER-5-UPDOWN: Controller DSL 0/0, changed state to down

Router(config-controller)# line-mode 4-wire
00:23:25: %CONTROLLER-5-UPDOWN: Controller DSL 0/0, changed state to up
00:23:31: %LINK-3-UPDOWN: Interface ATM0/0, changed state to up
00:23:32: %LINEPROTO-5-UPDOWN: Line protocol on Interface ATM0/0, changed state to up

Related Commands

Command
Description

controller dsl

Configures the DSL controller.


dsu bandwidth

To specify the maximum allowable bandwidth used by a T3 or E3 controller or the PA-T3 and PA-E3 port adapters, use the dsu bandwidth command in interface configuration mode. To return to the default bandwidth, use the no form of this command.

dsu bandwidth kbps

no dsu bandwidth

Syntax Description

kbps

Maximum bandwidth, in kbps. Range is from 22 to 44736. Default values are as follows:

34010 for E3 or PA-E3

44210 for T3

44736  for PA-T3


Defaults

34010 kbps for E3 or PA-E3
44210 kbps for T3
44736 kbps for PA-T3

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CA

This command was introduced.

12.2(11)YT

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

12.2(15)T

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


Usage Guidelines

The local interface configuration must match the remote interface configuration. For example, if you reduce the maximum bandwidth to 16000 on the local port, you must also do the same on the remote port.

The dsu bandwidth command reduces the bandwidth by padding the E3 and T3 frame.

To verify the data service unit (DSU) bandwidth configured on the interface, use the show interfaces serial EXEC command.

When G.751 framing is used, DSU bandwidth can be used to select a payload subrate from 34010 kbps down to 22 kbps. Before framing bypass can be used, a DSU bandwidth of 34010 kbps must be configured.

Even though software allows the user to configure a continuous range of bandwidths in subrate modes, vendors support bandwidths only in quantums (for example, in an E3 digital link, bandwidth must be in multiples of 358 kbps). Therefore, the software sets the user-configured bandwidth to the closest vendor-supported bandwidth. Use the show interfaces serial slot/port command to display the actual bandwidth that is configured.

The user-configured subrate mode, subrate bandwidth, actual subrate bandwidth configured, and scramble configuration are displayed near the end of the show interfaces serial command output.

Mode
DSU
Bandwidth Range
Bandwidth Multiples

0

Digital Link or Cisco

358-34010 kbps for E3

300-44210 kbps for T3

358 kbps

300.746 kbps

1

ADC Kentrox T3/E3 IDSU

1000-34010 kbps for E3

1500-44210 kbps for T3

500 kbps

500 kbps

2

Larscom Access T45

3100-44210 kbps

3158 kbps

3

Adtran T3SU 300

75-44210 kbps

75.186 kbps

4

Verilink HDM 2182

1500-44210 kbps

1579 kbps


The following table shows DSU modes and vendor-supported bandwidths.

Examples

The following example sets the maximum allowable DSU bandwidth to 16,000 kbps on interface 1/0/0:

Router(config)# interface serial 1/0/0
Router(config-if)# dsu bandwidth 16000

The following example shows the user-configured subrate bandwidth and the actual configured subrate bandwidth as displayed in the output of the show interfaces serial command:

Router# show interfaces serial

Serial1/0 is up, line protocol is up 
  Hardware is DSXPNM Serial
  MTU 1500 bytes, BW 44210 Kbit, DLY 20000 usec, 
     reliability 253/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, crc 16, loopback not set
  Keepalive not set
  DTR is pulsed for 0 seconds on reset, Restart-Delay is 1637167 secs
  Last input 04:59:04, output 04:59:04, output hang never
  Last clearing of "show interface" counters 00:00:02
  Input queue:0/75/0/0 (size/max/drops/flushes); Total output drops:0
  Queueing strategy:fifo
  Output queue :0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
 DSU mode 0, bandwidth 34010, real bandwidth 34010, scramble 0

Related Commands

Command
Description

show interfaces serial

Displays information that is specific to the interface hardware.


dsu mode

To specify the interoperability mode used by a T3 or E3 controller or the PA-T3 and PA-E3 port adapters, use the dsu mode command in interface configuration mode. To return to the default mode, use the no form of this command.

dsu mode {0 | 1 | 2 | 3 | 4}

no dsu mode

Syntax Description

0

Sets the interoperability mode to 0. This is the default. Specify mode 0 to connect an E3 controller to another E3 controller or to a Digital Link DSU (DL3100). Specify mode 0 to connect a PA-E3 port adapter to another PA-E3 port adapter or to a Digital Link DSU (DL3100). Use mode 0 to connect a PA-T3 port adapter to another PA-T3 port adapter or to a Digital Link DSU (DL3100).

1

Sets the interoperability mode to 1. Specify mode 1 to connect an E3 or T3 controller or a PA-E3 or PA-T3 port adapter to a Kentrox DSU.

2

Sets the interoperability mode to 2. Specify mode 2 to connect a T3 controller or a PA-T3 port adapter to a Larscom DSU.

3

Sets the interoperability mode to 3. Specify mode 3 to connect a T3 controller to an Adtran T3SU 300.

4

Sets the interoperability mode to 4. Specify mode 4 to connect a T3 controller to a Verilink HDM 2182.


Defaults

0

Command Modes

Interface configuration

Command History

Release
Modification

11.1 CA

This command was introduced.

12.2(11)YT

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

12.2(15)T

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


Usage Guidelines

Scrambling Support on T3 and E3 Serial Interfaces in DSU Mode 1

DSU mode 1 refers to Kentrox mode. If DSU mode is used on a T3 serial interface and the bandwidth is = > 35,000 bps, the scrambling option is not supported. Likewise, if DSU mode 1 is used for an E3 serial interface and the bandwidth is = > 24,510 bps, scrambling is not supported.

Match Local and Remote DSU Configurations

The local interface configuration must match the remote interface configuration. For example, if you define the data service unit (DSU) interoperability mode as 1 on the local port, you must also do the same on the remote port.

Know the DSU Type

You must know what type of DSU is connected to the remote port to determine if it interoperates with an E3 or T3 controller or a PA-E3 or PA-T3 port adapter. The dsu mode command enables and improves interoperability with other DSUs.

Verify DSU Mode

To verify the DSU mode configured on the interface, use the show controllers serial or show interfaces serial EXEC commands.

Examples

The following example sets the DSU mode to 1 on interface 1/0/0:

Router(config)# interface serial 1/0/0
Router(config-if)# dsu mode 1

The following example shows the configuration for a serial interface configured in DSU mode 1. The bandwidth is set higher than that supported by the Kentrox firmware allows for scrambling. therefore, the scrambling option is not supported in this configuration.

Router(config)# interface serial 1/0/0
Router(config-if)# mtu 4474
Router(config-if)# ip address 216.186.93.114 255.255.255.252
Router(config-if)# ip mtu 4470
Router(config-if)# dsu mode 1
Router(config-if)# dsu bandwidth 44210

Related Commands

Command
Description

show controllers serial

Displays information that is specific to the serial controllers.

show interfaces serial

Displays information that is specific to the interface hardware.


dte-invert-txc

To invert the transmit external clock (TXC) signal received from the DCE when the device is operating as a DTE, use the dte-invert-txc command in interface configuration mode. If the DCE accepts serial clock transmit external (SCTE) signal when the device is operating as a DTE, use the no form of this command.

dte-invert-txc

no dte-invert-txc

Syntax Description

This command has no arguments or keywords.

Defaults

The TXC signal is not inverted.

Command Modes

Interface configuration

Command History

Release
Modification

9.1

This command was introduced.


Usage Guidelines

Use this command if the DCE cannot receive SCTE from the DTE, the data is running at high speeds, and the transmission line is long. The dte-invert-txc command prevents phase shifting of the data with respect to the clock.

On the Cisco 4000 series, you can specify the serial Network Processor Module timing signal configuration. When the board is operating as a DTE, the dte-invert-txc command inverts the TXC clock signal it gets from the DCE that the DTE uses to transmit data.

If the DCE accepts SCTE from the DTE, use no dte-invert-txc.

Examples

The following example inverts the TXC on serial interface 0:

Router(config)# interface serial 0
Router(config-if)# dte-invert-txc

duplex

To configure duplex operation on an interface, use the duplex command in interface configuration mode. To return the system to half-duplex mode, the system default, use the no form of this command.

duplex {full | half | auto}

no duplex

Syntax Description

full

Specifies full-duplex operation.

half

Specifies half-duplex operation. This is the default.

auto

Specifies the autonegotiation capability. The interface automatically operates at half or full duplex, depending on environmental factors, such as the type of media and the transmission speeds for the peer routers, hubs, and switches used in the network configuration.


Defaults

Half-duplex mode

Command Modes

Interface configuration

Command History

Release
Modification

11.2(10)P

This command was introduced.


Usage Guidelines

To use the autonegotiation capability (that is, detect speed and duplex modes automatically), you must set both speed and duplex to auto.

Table 7 describes the access server's performance for different combinations of the duplex and speed modes. The specified duplex command configured with the specified speed command produces the resulting system action.

Table 7 Relationship Between duplex and speed Commands 

duplex Command
speed Command
Resulting System Action

duplex auto

speed auto

Autonegotiates both speed and duplex modes.

duplex auto

speed 100 or speed 10

Autonegotiates both speed and duplex modes.

duplex half or duplex full

speed auto

Autonegotiates both speed and duplex modes.

duplex half

speed 10

Forces 10 Mbps and half duplex.

duplex full

speed 10

Forces 10 Mbps and full duplex.

duplex half

speed 100

Forces 100 Mbps and half duplex.

duplex full

speed 100

Forces 100 Mbps and full duplex.


For the Cisco AS5300, the duplex {full | half | auto} command syntax replaces the following two earlier duplex commands:

half-duplex

full-duplex

You will get the following error messages if you try to use these commands on a Cisco AS5300:

Router(config)# interface fastethernet 0
Router(config-if)# full-duplex 
Please use duplex command to configure duplex mode
Router(config-if)#
Router(config-if)# half-duplex 
Please use duplex command to configure duplex mode

Examples

The following example shows how to configure full- duplex operation on a Cisco AS5300:

Router(config)# interface fastethernet 0
Router(config-if)# duplex full

Related Commands

Command
Description

interface fastethernet

Selects a particular Fast Ethernet interface for configuration.

show controllers fastethernet

Displays information about initialization block information, transmit ring, receive ring, and errors for the Fast Ethernet controller chip on the Cisco 4500, Cisco 7200 series, or Cisco 7500 series routers.

speed

Configures the speed for a Fast Ethernet interface.


e2-clockrate

To configure serial interface 0 for E2 (8 MHz full duplex) and to shut down the other three serial interfaces (1 to 3), use the e2-clockrate command in interface configuration mode. To disable the full duplex E2, use the no form of this command.

e2-clockrate

no e2-clockrate

Syntax Description

This command has no arguments or keywords.

Defaults

All interfaces are running.

Command Modes

Interface configuration

Command History

Release
Modification

12.0(2)XD

This command was introduced.

12.0(3)T

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


Usage Guidelines

The e2-clockrate command is an interface configuration command and is seen only with interface serial0. When this command is used, serial interface 0 supports speeds up to E2 (8 MHz full duplex) and the other three serial interfaces (1 to 3) are put in the "shutdown" state. Also, running this command displays the following warning message:

Serial interface 0 is configured to support E2 rates and serial ports "1-3" are moved to 
shutdown state.

Examples

The following example shows sample display output for the e2-clockrate EXEC command.

Router(config-if)# e2-clockrate
Interface Serial 0 is configured to support clockrates up to E2 (8Mbps)
Interfaces serial 1-3 will not be operational

Related Commands

Command
Description

clock rate

Configures the clock rate for the hardware connections on serial interfaces such as NIMs and interface processors to an acceptable bit rate.


early-token-release

To enable early token release on Token Ring interfaces, use the early-token-release command in interface configuration mode. To disable this function, use the no form of this command.

early-token-release

no early-token-release

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled

Command Modes

Interface configuration

Command History

Release
Modification

10.0

This command was introduced.


Usage Guidelines

Early token release is a method whereby the Token Ring interfaces can release the token back onto the ring immediately after transmitting, rather than waiting for the frame to return. This feature helps increase the total bandwidth of the Token Ring.

The Token Ring Interface Processor (TRIP) on the Cisco 7500 series routers and the Token Ring adapters on the Cisco 7200 series routers all support early token release.

Examples

The following example enables the use of early token release on Token Ring interface 1:

Router(config)# interface tokenring 1
Router(config-if)# early-token-release

The following example enables the use of early token release on the Token Ring interface processor in slot 4 on port 1 on the Cisco 7500 series routers:

Router(config)# interface tokenring 4/1
Router(config-if)# early-token-release

encapsulation

To set the encapsulation method used by the interface, use the encapsulation command in interface configuration mode. To remove the encapsulation, use the no form of this command.

encapsulation encapsulation-type

no encapsulation encapsulation-type

Syntax Description

encapsulation-type   

Encapsulation type; one of the following keywords:

atm-dxi—ATM Mode-Data Exchange Interface.

bstun—Block Serial Tunnel.

dot1q vlan-id [native]—Enables IEEE 802.1q encapsulation of traffic on a specified subinterface in VLANs. The vlan-id argument is a virtual LAN identifier. The valid range is from 1 to 1000. The optional native keyword sets the PVID value of the port to the vlan-id value.

frame-relay—Frame Relay (for serial interface).

hdlc—High-Level Data Link Control (HDLC) protocol for serial interface. This encapsulation method provides the synchronous framing and error detection functions of HDLC without windowing or retransmission. This is the default for synchronous serial interfaces.

isl vlan-id—Inter-Switch Link (ISL) (for VLANs).

lapb—X.25 Link Access Procedure, Balanced. Data link layer protocol (LAPB) DTE operation (for serial interface).

ppp—PPP (for serial interface).

sde said—IEEE 802.10. The said argument is a security association identifier. This value is used as the VLAN identifier. The valid range is from 0 to 0xFFFFFFFE.

sdlc—IBM serial Systems Network Architecture (SNA).

sdlc-primary—IBM serial SNA (for primary serial interface).

sdlc-secondary—IBM serial SNA (for secondary serial interface).

slip—Specifies Serial Line Internet Protocol (SLIP) encapsulation for an interface configured for dedicated asynchronous mode or dial-on-demand routing (DDR). This is the default for asynchronous interfaces.

smds—Switched Multimegabit Data Services (SMDS) (for serial interface).

ss7—Sets the encapsulation type to SS7 and overrides the serial interface objects high-level data link control (HDLC) default.


Defaults

The default depends on the type of interface. For example, synchronous serial interfaces default to HDLC and asynchronous interfaces default to SLIP.

Command Modes

Interface configuration