Table of Contents

Feature Overview

Traffic Shaping on Switched PVCs
Frame Relay Switching over ISDN B Channels
Traffic Policing on UNI DCE
Congestion Management on Switched PVCs

Benefits
Restrictions
Related Documents

Supported Platforms
Supported Standards, MIBs, and RFCs
Prerequisites
Configuration Tasks

Creating Switched PVCs
Identifying a PVC As Switched
Enabling Frame Relay Policing on the Interface
Configuring Frame Relay Policing Parameters
Configuring Congestion Management on the Interface
Configuring Frame Relay Congestion Management on Traffic-Shaping Queues
Verifying Frame Relay Policing
Verifying Frame Relay Congestion Management

Monitoring and Maintaining Frame Relay Policing and Congestion Management
Configuration Examples

Configuring Traffic Shaping on Switched PVCs Example
Configuring Frame Relay Switching over ISDN B Channels Example
Configuring Traffic Policing on a UNI DCE Example
Configuring Congestion Management on Switched PVCs Example
Configuring Congestion Management on the Traffic-Shaping Queue of a Switched PVC Example

Command Reference
connect (Frame Relay)
frame-relay congestion-management
frame-relay congestion threshold de
frame-relay congestion threshold ecn
frame-relay holdq
frame-relay interface-dlci
frame-relay policing
frame-relay tc
show frame-relay pvc
show interfaces serial
threshold de
threshold ecn
Glossary

Frame Relay Switching Enhancements

This feature module describes the Frame Relay Switching Enhancements feature. It includes information on the benefits of this new feature, supported platforms, related documents, and so on.

This document includes the following sections:

• Feature Overview

• Supported Platforms

• Supported Standards, MIBs, and RFCs

• Prerequisites

• Configuration Tasks

• Monitoring and Maintaining Frame Relay Policing and Congestion Management

• Configuration Examples

• Command Reference

• Glossary

Feature Overview

The Frame Relay Switching Enhancements feature enables a router in a Frame Relay network to be used as a Frame Relay switch.

This feature includes the following Frame Relay switching enhancements:

• Traffic Shaping on Switched PVCs

• Frame Relay Switching over ISDN B Channels

• Traffic Policing on UNI DCE

• Congestion Management on Switched PVCs

Traffic Shaping on Switched PVCs

You can now configure Frame Relay traffic shaping on switched permanent virtual circuits (PVCs). By applying traffic shaping to switched PVCs you enable a router to be used as a Frame Relay port concentrator in front of a Frame Relay switch. The Frame Relay switch will shape the concentrated traffic before sending it into the network. Figure 1 shows the network configuration.

To create switched PVCs, use the connect global configuration command. To configure traffic shaping, define the traffic-shaping parameters in a Frame Relay map class, identify the PVC as switched using the frame-relay interface-dlci interface command, and then attach the map class to the interface or a single switched PVC. All the traffic-shaping map-class parameters are applicable to switched PVCs: namely, Bc, Be, CIR, minimum CIR, average rate, peak rate, and adaptive shaping.

Frame Relay traffic shaping must be enabled on the interface before traffic-shaping map-class parameters will be effective. Note that when you enable Frame Relay traffic shaping, all PVCs, switched and terminated, will be shaped on that interface. Switched PVCs that are not associated with a map class will inherit shaping parameters from the interface or use default values.

The traffic-shaping enhancement to switched PVCs also allows you to set a maximum queue size for use with FIFO default queueing. To set the maximum FIFO queue size, use the frame-relay holdq map-class command. The default value is 40 packets, and the allowable range is from1 to 512.

Frame Relay Switching over ISDN B Channels

The Frame Relay Switching Enhancements feature enables you to transport Frame Relay data over ISDN to allow small offices to be hubbed out of larger offices rather than connecting them directly to the core network. The hub router acts as a Frame Relay switch, switching between ISDN and serial interfaces, as shown in Figure2.

The Frame Relay switching over ISDN enhancement provides the following functionality:

• The Local Management Interface (LMI) mechanism that previously operated only on serial Frame Relay DCE interfaces now also operates on ISDN Frame Relay DCE interfaces.

• A single BRI/PRI interface can use a combination of switched PVCs and terminated Frame Relay PVCs.

• Frame Relay switching supports both leased-line ISDN, on which a B channel is permanently connected, and switched ISDN, on which B channels may be dynamically set up and torn down.

To configure Frame Relay switching over ISDN, use the connect global configuration command.

Traffic Policing on UNI DCE

The Frame Relay Switching Enhancements feature brings traffic policing functionality to User-Network Interface (UNI) DCEs in Frame Relay networks. Shaping affects outgoing traffic, and policing operates on incoming PVC traffic. When enabled on the interface, policing prevents traffic congestion by discarding or setting the DE bit on packets that exceed specified traffic parameters.

To enable Frame Relay policing on all switched PVCs on the interface, use the frame-relay policing interface command. To configure traffic policing, define policing parameters in a Frame Relay map class using the CIR, Bc, Be and Tc parameters. You can associate the map class with the interface or individual switched PVCs. Switched PVCs that are not associated with a map class will inherit policing parameters from the interface.

The CIR, Bc, Be, and Tc parameters are also used to configure traffic shaping. If you are going to use a map class to configure both policing and shaping, use the in and out keywords to distinguish between incoming and outgoing traffic. If you configure both shaping and policing on a switched PVC, the shaping parameters will be derived from the policing parameters unless you specifically define shaping parameters in the map class.

Congestion Management on Switched PVCs

The Frame Relay Switching Enhancements feature enables a router in a Frame Relay network to manage outgoing traffic congestion on switched PVCs. When Frame Relay congestion management is enabled, one way that the router manages congestion is by setting backward explicit congestion notification (BECN) and forward explicit congestion notification (FECN) bits on packets. When a switched PVC or interface is congested, packets experiencing congestion are marked with the FECN bit, and packets traveling in the reverse direction are marked with the BECN bit. When these bits reach a user device at the end of the network, the user device can react to the ECN bits and adjust the flow of traffic.

A second way the router manages congestion is by discarding Frame Relay packets that are marked with the discard eligible (DE) bit and that exceed a specified level of congestion.

You can define two levels of congestion. The first level applies to individual PVCs transmitting traffic in excess of the committed information rate (CIR). The second level applies to all PVCs at an interface. This scheme allows you to adjust the congestion on PVCs transmitting above the CIR before applying congestion management measures to all PVCs.

Congestion management parameters can be configured on the output interface queue and on traffic-shaping queues. To configure congestion management on the output interface queue, first enable congestion management using the frame-relay congestion-management interface command. Then configure the explicit congestion notice (ECN) excess, ECN committed, and DE thresholds using the threshold ecn and threshold de frame relay congestion management commands.

When the output interface queue reaches or exceeds the ECN excess threshold, all Frame Relay DE bit packets on all PVCs crossing that interface will be marked with FECN or BECN, depending on their direction of travel. When the queue reaches or exceeds the ECN committed threshold, all Frame Relay packets will be marked with FECN or BECN.

When the queue reaches or exceeds the DE threshold, Frame Relay packets with the DE bit will be discarded rather than queued.

To configure per-PVC congestion management on traffic-shaping queues, use the frame-relay congestion threshold ecn and frame-relay congestion threshold de map-class commands. You can configure one ECN threshold for each traffic-shaping queue.

Benefits

Before the Frame Relay Switching Enhancements feature was introduced, routers had limited Frame Relay switching functionality. With this feature, a router acting as a virtual Frame Relay switch can be configured to do the following:

• Apply Frame Relay traffic shaping functionality to switched PVCs, enabling the router to act as a Frame Relay port concentrator.

• Support ISDN interfaces in addition to serial interfaces.

• Discard switched packets with the DE bit set when there is network congestion.

• Police incoming traffic to ensure adherence to service contracts.

• Set the Forward/Backward Explicit Congestion Notification (FECN/BECN) bits in switched packets when there is network congestion.

• Apply FRF.12 fragmentation to switched PVCs.

Restrictions

• The Frame Relay switching enhancements can be configured on the interface or individual PVCs; however, they cannot be configured on Frame Relay subinterfaces.

• The traffic-shaping enhancement does not support priority queueing or custom queueing.

• Frame Relay traffic shaping cannot be configured on ISDN interfaces.

• The router configured for Frame Relay switching over ISDN cannot initiate the ISDN call.

Related Documents

• Cisco IOS Wide-Area Networking Configuration Guide, Release 12.1

• Cisco IOS Wide-Area Networking Command Reference, Release 12.1

• FRF.12 Support on Switched Frame Relay PVCs, Cisco IOS Release 12.1(2)T

Supported Platforms

• Cisco 1600

• Cisco 2500 series

• Cisco 2600

• Cisco 3600 series

• Cisco 4000 series (Cisco 4000, 4000-M, 4500, 4500-M, 4700, 4700-M)

• Cisco 7200 series

• Cisco 7500 series (in nondistributed mode)

Supported Standards, MIBs, and RFCs

Standards

No new or modified standards are supported by this feature.

MIBs

No new or modified MIBs are supported by this feature.

For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on Cisco Connection Online (CCO) at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

RFCs

No new or modified RFCs are supported by this feature.

Prerequisites

• Frame Relay switching must be enabled on the router before you can configure any of the Frame Relay switching enhancements. To enable Frame Relay switching, use the frame-relay switching global command.

• Frame Relay traffic shaping must be enabled on the outgoing interface before you can configure traffic shaping on switched PVCs. To enable Frame Relay traffic shaping, use the frame-relay traffic-shaping interface command.

• Frame Relay policing must be enabled on the incoming interface before you can configure traffic policing parameters. To enable Frame Relay policing, use the frame-relay policing interface command.

• Congestion management must be enabled on the outgoing interface before you can configure congestion management on switched PVCs. To enable congestion management, use the frame-relay congestion-management interface command.

• Switched PVCs must be created using the connect command.

Configuration Tasks

See the following sections for configuration tasks for the Frame Relay Switching Enhancements feature. Each task in the list is indicated as optional or required.

• Creating Switched PVCs

• Identifying a PVC As Switched

• Enabling Frame Relay Policing on the Interface

• Configuring Frame Relay Policing Parameters

• Configuring Congestion Management on the Interface

• Configuring Frame Relay Congestion Management on Traffic-Shaping Queues

Creating Switched PVCs

To create switched PVCs, use the following command in global configuration mode:

Command	Purpose
Router(config)#connect connection-name interface dlci interface dlci	Defines connections between Frame Relay PVCs.

Identifying a PVC As Switched

Before you can associate a map class with a switched PVC, you must identify the PVC as being switched. To identify a PVC as switched, use the following command in interface configuration mode:

Command	Purpose
Router(config-if)#frame-relay interface-dlci dlci [ietf | cisco] [voice-encap size] [voice-cir cir] [ppp virtual-template-name] [switched]	Identifies a PVC as switched.

Enabling Frame Relay Policing on the Interface

To enable Frame Relay policing on a interface, use the following command in interface configuration mode:

Command	Purpose
Router(config-if)#frame-relay policing	Enables Frame Relay policing on all switched PVC s on the interface.

Configuring Frame Relay Policing Parameters

To configure policing parameters in a Frame Relay map class, use one or more of the following commands in map-class configuration mode:

Command	Purpose
Router(config-map-class)#frame-relay cir {in | out} bps	Sets the CIR for a Frame Relay PVC.
Router(config-map-class)#frame-relay bc {in | out} bits	Sets the committed burst size for a Frame Relay PVC.
Router(config-map-class)#frame-relay be {in | out} bits	Sets the excess burst size for a Frame Relay PVC.
Router(config-map-class)#frame-relay tc milliseconds	Sets the measurement interval for policing incoming traffic on a PVC when the CIR is zero.

Configuring Congestion Management on the Interface

To configure Frame Relay congestion management on all switched PVCs on an interface, use the following commands beginning in interface configuration mode:

	Command	Purpose
Step 1	Router(config-if)#frame-relay congestion management	Enables Frame Relay congestion management on all switched PVCs on an interface and enters Frame Relay congestion management configuration mode.
Step 2	Router(config-fr-congest)#threshold de percentage	Configures the threshold at which DE-marked packets will be discarded from switched PVCs on the output interface.
Step 3	Router(config-fr-congest)#threshold ecn {bc | be} percentage	Configures the threshold at which ECN bits will be set on packets in switched PVCs on the output interface.

Configuring Frame Relay Congestion Management on Traffic-Shaping Queues

To configure Frame Relay congestion management on the traffic-shaping queues of switched PVCs, use one or more of the following commands in map-class configuration mode:

Command	Purpose
Router(config-map-class)#frame-relay congestion threshold de percentage	Configures the threshold at which DE-marked packets will be discarded from the traffic-shaping queue of a switched PVC.
Router(config-map-class)#frame-relay congestion threshold ecn percentage	Configures the threshold at which ECN bits will be set on packets in the traffic-shaping queue of a switched PVC.
Router(config-map-class)#frame-relay holdq queue-size	Configures the maximum size of a traffic-shaping queue on a switched PVC.

Verifying Frame Relay Policing

To verify Frame Relay policing on switched PVCs, use the following command in privileged EXEC mode:

Command	Purpose
Router#show frame-relay pvc [interface interface] [dlci]	Displays statistics about PVCs for Frame Relay interfaces.

Verifying Frame Relay Congestion Management

To verify Frame Relay congestion management on switched PVCs, use the following commands:

Command	Purpose
Router#show frame-relay pvc [interface interface] [dlci]	Displays statistics about PVCs for Frame Relay interfaces.
Router#show interfaces serial number	Displays information about the configuration and queue at the interface.

Monitoring and Maintaining Frame Relay Policing and Congestion Management

To monitor Frame Relay policing and congestion management, use the following commands:

Command	Purpose
Router#show frame-relay pvc [interface interface] [dlci]	Displays statistics about PVCs for Frame Relay interfaces.
Router#show interfaces serial number	Displays information about the configuration and queue at the interface.

Configuration Examples

This section provides the following configuration examples:

• Configuring Traffic Shaping on Switched PVCs Example

• Configuring Frame Relay Switching over ISDN B Channels Example

• Configuring Traffic Policing on a UNI DCE Example

• Configuring Congestion Management on Switched PVCs Example

• Configuring Congestion Management on the Traffic-Shaping Queue of a Switched PVC Example

Configuring Traffic Shaping on Switched PVCs Example

In the example that follows, traffic on serial interface 0 is being shaped prior to entry to the Frame Relay network. PVC 100/16 is shaped according to the "shape256K" class. PVC 200/17 is shaped using the "shape64K" class inherited from the interface.

frame-relay switching
  !
  interface serial0
    encapsulation frame-relay
    frame-relay intf-type dce
    frame-relay traffic-shaping
    frame-relay class shape64K
    frame-relay interface-dlci 16 switched
      class shape256K
  !
  interface serial1
    encapsulation frame-relay
    frame-relay intf-type dce
  !
  connect one serial0 16 serial1 100
  connect two serial0 17 serial1 200
  !
  map-class frame-relay shape256K
    frame-relay traffic-rate 256000 512000
  !
  map-class frame-relay shape64K
    frame-relay traffic-rate 64000 64000
 

Configuring Frame Relay Switching over ISDN B Channels Example

The following example illustrates Frame Relay switching over an ISDN dialer interface:

frame-relay switching
  !
  interface BRI0
    isdn switch-type basic-5ess
    dialer pool-member 1
    dialer pool-member 2
  !
  interface dialer1
    encapsulation frame-relay
    dialer pool 1
    dialer-group 1
    dialer caller 60038
    dialer string 60038
    frame-relay intf-type dce
  !
  interface dialer2
    encapsulation frame-relay
    dialer pool 2
    dialer-group 1
    dialer caller 60039
    dialer string 60039
    frame-relay intf-type dce
  !
  interface serial0
    encapsulation frame-relay
    frame-relay intf-type dce
  !
  connect one serial0 16 dialer1 100
  connect two serial0 17 dialer2 100
  dialer-list 1 protocol ip permit
 

Configuring Traffic Policing on a UNI DCE Example

In the following example, incoming traffic is being policed on serial interface 1. The interface uses policing parameters configured in map class "police256K." PVC 100/16 inherits policing parameters from the interface. PVC 200/17 uses policing parameters configured in "police64K."

  frame-relay switching
  !
  interface serial0
    encapsulation frame-relay
    frame-relay intf-type dce
  !
  interface serial1
    encapsulation frame-relay
    frame-relay policing
    frame-relay class police256K
    frame-relay intf-type dce
    frame-relay interface-dlci 200 switched
      class police64K
  !
  connect one serial0 16 serial1 100
  connect two serial0 17 serial1 200
  !
  map-class frame-relay police256K
    frame-relay cir 256000
    frame-relay bc 256000
    frame-relay be 0
  !
  map-class frame-relay police64K
    frame-relay cir 64000
    frame-relay bc 64000
    frame-relay be 64000

Configuring Congestion Management on Switched PVCs Example

The following example illustrates the configuration of congestion management and DE discard levels for all switched PVCs on serial interface 1. Policing is configured on PVC 16.

  frame-relay switching
  !
  interface serial0
    encapsulation frame-relay
    frame-relay intf-type dce
    frame-relay policing
    frame-relay interface-dlci 16 switched
      class 256K
  !
  interface serial1
    encapsulation frame-relay
    frame-relay intf-type dce
    frame-relay congestion-management
      threshold ecn be 0
      threshold ecn bc 20
      threshold de 40
  !
  connect one serial1 100 serial0 16
  !
  map-class frame-relay 256K
    frame-relay cir 256000
    frame-relay bc 256000
    frame-relay be 256000

Configuring Congestion Management on the Traffic-Shaping Queue of a Switched PVC Example

The following example illustrates the configuration of congestion management in a class called perpvc_congestion. The class is associated with the traffic-shaping queue of DLCI 200 on serial interface 3.

  map-class frame-relay perpvc_congestion
    frame-relay holdq 100
    frame-relay congestion threshold ecn 50
 
  interface Serial3
    frame-relay traffic-shaping
    frame-relay interface-dlci 200 switched
      class perpvc_congestion

Command Reference

This section documents new or modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.1 command reference publications.

connect (Frame Relay)

To define connections between Frame Relay PVCs, use the connect global configuration command. To remove connections, use the no form of this command.

Syntax Description

connection-name	A name for this connection.
interface	Interface on which a PVC connection will be defined.
dlci	Data-link connection identifier (DLCI) number of PVC that will be connected.

Defaults

No default behavior or values.

Command Modes

Global configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

When Frame Relay switching is enabled, the connect command creates switched PVCs in Frame Relay networks.

Examples

The following example shows how to enable Frame Relay switching and define a connection called "one" between DLCI 16 on serial interface 0 and DLCI 100 on serial interface 1.

frame-relay switching
connect one serial0 16 serial1 100

Related Commands

Command	Description
frame-relay switching	Enables PVC switching on a Frame Relay DCE or NNI.

frame-relay congestion-management

To enable Frame Relay congestion management functions on all switched PVCs on an interface, and to enter Frame Relay congestion management configuration mode, use the frame-relay congestion-management interface configuration command. To disable Frame Relay congestion management, use the no form of this command.

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values.

Command Modes

Interface configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

You must enable Frame Relay switching, using the frame-relay switching global command, before you can configure Frame Relay congestion management.

Frame Relay congestion management is supported only when the interface is configured with FIFO queueing, weighted fair queueing (WFQ), or PVC interface priority queueing (PIPQ).

Examples

In the following example, the frame-relay congestion-management command enables Frame Relay congestion management on serial interface 1. The command also enters Frame Relay congestion management configuration mode so that congestion threshold parameters can be configured.

interface serial1
    encapsulation frame-relay
    frame-relay intf-type dce
    frame-relay congestion-management
      threshold ecn be 0
      threshold ecn bc 20
      threshold de 40
 

Related Commands

Command	Description
frame-relay congestion threshold de	Configures the threshold at which DE-marked packets will be discarded from the traffic-shaping queue of a switched PVC.
frame-relay congestion threshold ecn	Configures the threshold at which ECN bits will be set on packets in the traffic-shaping queue of a switched PVC.
threshold de	Configures the threshold at which DE-marked packets will be discarded from switched PVCs on the output interface.
threshold ecn	Configures the threshold at which ECN bits will be set on packets in switched PVCs on the output interface.

frame-relay congestion threshold de

To configure the threshold at which DE-marked packets will be discarded from the traffic-shaping queue of a switched PVC, use the frame-relay congestion threshold de map-class command. To reconfigure the threshold, use the no form of this command.

Syntax Description

percentage

Threshold at which DE-marked packets will be discarded, specified as a percentage of the maximum queue size.

Defaults

100%.

Command Modes

Map-class configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

The frame-relay congestion threshold de command applies only to default FIFO traffic-shaping queues.

You must enable Frame Relay switching, using the frame-relay switching global command, before Frame Relay congestion management parameters will be effective on switched PVCs.

Examples

The following example illustrates the configuration of the DE congestion threshold in the Frame Relay map class called perpvc_congestion:

map-class frame-relay perpvc_congestion
          frame-relay congestion threshold de 50

Related Commands

Command	Description
frame-relay congestion management	Enables Frame Relay congestion management functions on all switched PVCs on an interface, and enters congestion management configuration mode.
frame-relay congestion threshold ecn	Configures the threshold at which ECN bits will be set on packets in the traffic-shaping queue of a switched PVC.
threshold de	Configures the threshold at which DE-marked packets will be discarded from switched PVCs on the output interface.
threshold ecn	Configures the threshold at which ECN bits will be set on packets in switched PVCs on the output interface.

frame-relay congestion threshold ecn

To configure the threshold at which ECN bits will be set on packets in the traffic-shaping queue of a switched PVC, use the frame-relay congestion threshold ecn map-class command. To reconfigure the threshold, use the no form of this command.

Syntax Description

percentage

Threshold at which ECN bits will be set on packets, specified as a percentage of the maximum queue size.

Defaults

100%.

Command Modes

Map-class configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

The frame-relay congestion threshold ecn command applies only to default FIFO traffic-shaping queues.

One ECN threshold applies to all traffic on a traffic-shaping queue. You cannot configure separate thresholds for committed and excess traffic.

You must enable Frame Relay switching, using the frame-relay switching global command, before the frame-relay congestion threshold ecn command will be effective on switched PVCs.

Examples

The following example illustrates the configuration of the ECN congestion threshold in the Frame Relay map class called perpvc_congestion:

map-class frame-relay perpvc_congestion
          frame-relay congestion threshold ecn 50

Related Commands

Command	Description
frame-relay congestion management	Enables Frame Relay congestion management functions on all switched PVCs on an interface, and enters congestion management configuration mode.
frame-relay congestion threshold de	Configures the threshold at which DE-marked packets will be discarded from the traffic-shaping queue of a switched PVC.
threshold de	Configures the threshold at which DE-marked packets will be discarded from switched PVCs on the output interface.
threshold ecn	Configures the threshold at which ECN bits will be set on packets in switched PVCs on the output interface.

frame-relay holdq

To configure the maximum size of a traffic-shaping queue on a switched PVC, use the frame-relay holdq map-class configuration command. To reconfigure the size of the queue, use the no form of this command.

Syntax Description

queue-size

Size of the traffic-shaping queue as specified in maximum number of packets. The range is from 1 to 512.

Defaults

40 packets.

Command Modes

Map-class configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

You must enable Frame Relay traffic shaping, using the frame-relay traffic-shaping interface command, before frame-relay holdq and other traffic-shaping map-class commands will be effective.

You must enable Frame Relay switching, using the frame-relay switching global command, before the frame-relay holdq command will be effective on switched PVCs.

The frame-relay holdq command can be applied to switched PVCs that use FIFO default queueing.

Examples

The following example illustrates the configuration of the maximum size of the traffic-shaping queue on a switched PVC. The queue size is configured in a map class called perpvc_congestion:

map-class frame-relay perpvc_congestion
          frame-relay holdq 100
 

Related Commands

Command	Description
frame-relay switching	Enables PVC switching on a Frame Relay DCE or Network-to-Network Interface (NNI).
frame-relay traffic-shaping	Enables both traffic shaping and per-PVC queueing for all PVCs and switched virtual circuits (SVCs) on a Frame Relay interface.

frame-relay interface-dlci

To assign a data-link connection identifier (DLCI) to a specified Frame Relay subinterface on the router or access server, or to define a specific permanent virtual circuit (PVC) to a DLCI and apply a virtual template configuration for a PPP session, or to identify a PVC as switched, use the frame-relay interface-dlci interface configuration command. To remove this assignment, use the no form of this command.

---

Note   On the Cisco MC3810 only, the voice-encap option performs the same function as the vofr cisco interface configuration command introduced in Cisco IOS Release 12.0(3)XG. Either command is required in order to enable Voice over Frame Relay. The voice-encap option and the vofr cisco command are mutually exclusive on the same interface; you must choose which command to use. The voice-encap option does not support any priority queueing function, which provides greater throughput. The vofr cisco command uses weighted fair queueing, which reduces throughput but provides a means of prioritizing traffic flows.

---

The voice-cir option on the Cisco MC3810 provides call admission control; it does not provide traffic shaping. A call setup will be refused if the unallocated bandwidth available at the time of the request is not at least equal to the value of the voice-cir option.

When configuring the voice-cir option on the Cisco MC3810 for Voice over Frame Relay, do not set the value of this option to be higher than the physical link speed. If Frame Relay traffic shaping is enabled for a PVC sharing voice and data, do not configure the voice-cir option to be higher than the value set with the frame-relay mincir command. Note that voice traffic is not shaped when the voice-encap option is configured; thus, in this case the frame-relay mincir command is irrelevant.

---

Note   On the Cisco MC3810 only, the voice-cir option performs the same function as the frame-relay voice bandwidth map-class configuration command introduced in Cisco IOS Release 12.0(3)XG.

---

For more information about automatically installing router configuration files over a Frame Relay network, see the chapter "Loading System Images and Microcode" in the Cisco IOS Configuration Fundamentals Configuration Guide.

Examples

In the following example, DLCI 16 on serial interface 0 is identified as a switched PVC and is associated with a map class called "shape256K."

interface serial0
    encapsulation frame-relay
    frame-relay interface-dlci 16 switched
      class shape256K

In the following example, DLCI 100 is assigned to serial subinterface 5.17:

! Enter interface configuration and begin assignments on interface serial 5
interface serial 5
! Enter subinterface configuration by assigning subinterface 17
interface serial 5.17
! Now assign a DLCI number to subinterface 5.17
frame-relay interface-dlci 100
 

In the following example, DLCI 26 over subinterface serial 1.1 is specified, and the characteristics under virtual-template 2 are assigned to this PPP connection:

Router(config)# interface serial1.1 point-to-point
Router(config-if)# frame-relay interface-dlci 26 ppp virtual-template2
 

The following example shows an Annex G connection being created by assigning the X.25 profile "NetworkNodeA" to the Frame Relay DLCI interface 20 on interface serial 1 (after Frame Relay encapsulation has been enabled on that interface):

Router(config)# interface serial1
Router(config-if)# encapsulation frame-relay
Router(config-if)# frame-relay interface-dlci 20
Router(config-fr-dlci)# x25-profile NetworkNodeA
 

The following example shows assigning DLCI 100 to serial subinterface 5.17:

Router(config)# interface serial 5
Router(config-if)# interface serial 5.17
Router(config-if)# frame-relay interface-dlci 100
 

The following example shows assigning DLCI 100 to a serial interface, starting from global configuration mode:

router(config)# interface serial 1/1
router(config-if)# frame-relay interface-dlci 100
router(config-fr-dlci)# 
 

The following example shows enabling Voice over Frame Relay on DLCI 100 on a Cisco MC3810 and setting the data fragmentation size to 80 bytes:

router(config)# interface serial0
router(config-if)# frame-relay interface-dlci 100 voice-encap 80
router(config-fr-dlci)# 
 

The following example shows enabling Voice over Frame Relay on DLCI 100 on a Cisco MC3810, setting the data fragmentation size to 80 bytes, and setting the voice CIR to 24000 bps:

router(config)# interface serial0
router(config-if)# frame-relay interface-dlci 100 voice-encap 80 voice-cir 24000
router(config-fr-dlci)# 

Related Commands

Command	Description
frag-pre-queuing	Sets the queueing on a Frame Relay or HDLC interface to occur after fragmentation.
frame-relay class	Associates a map class with an interface or subinterface.
frame-relay switching	Enables PVC switching on a Frame Relay DCE or NNI.
show frame-relay pvc	Displays statistics about PVCs for Frame Relay interfaces.
show interface	Displays P1024B/C information.
vofr	Configures subchannels and enables Voice over Frame Relay for a specific DLCI.

frame-relay policing

To enable Frame Relay policing on all switched PVCs on the interface, use the frame-relay policing interface configuration command. To disable Frame Relay policing, use the no form of this command.

Syntax Description

This command has no arguments or keywords.

Defaults

Disabled.

Command Modes

Interface configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

You must enable Frame Relay policing on the incoming interface before you can configure traffic-policing parameters.

You must enable Frame Relay switching, using the frame-relay switching global command, before the frame-relay policing command will be effective on switched PVCs.

Examples

The following example shows the configuration of Frame Relay policing on serial interface 0:

interface serial0
    frame-relay policing

Related Commands

Command	Description
frame-relay bc	Specifies the incoming or outgoing committed burst size (Bc) for a Frame Relay virtual circuit.
frame-relay be	Specifies the incoming or outgoing excess burst size (Be) for a Frame Relay virtual circuit.
frame-relay cir	Specifies the incoming or outgoing committed information rate (CIR) for a Frame Relay virtual circuit.
frame-relay switching	Enables PVC switching on a Frame Relay DCE or NNI.
frame-relay tc	Specifies the measurement interval for policing incoming traffic when the CIR is zero.

frame-relay tc

To set the measurement interval for policing incoming traffic when the CIR is zero, use the frame-relay tc map-class configuration command. To reset the measurement interval for policing, use the no form of this command.

Syntax Description

milliseconds

Time interval from 10 ms to 10,000 ms during which incoming traffic cannot exceed Bc plus Be.

Defaults

1000 ms.

Command Modes

Map-class configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

You must enable Frame Relay policing on the incoming interface, using the frame-relay policing interface command, before you can configure traffic policing parameters.

You must enable Frame Relay switching, using the frame-relay switching global command, before the frame-relay tc command will be effective on switched PVCs.

When the CIR is greater than 0, Tc is equal to Bc divided by the CIR.

Examples

The following example shows how to configure a policing measurement interval of 800 milliseconds within a map class called "police":

map-class frame-relay police
    frame-relay tc 800
 

Related Commands

Command	Description
frame-relay bc	Specifies the incoming or outgoing committed burst size (Bc) for a Frame Relay virtual circuit.
frame-relay be	Specifies the incoming or outgoing excess burst size (Be) for a Frame Relay virtual circuit.
frame-relay cir	Specifies the incoming or outgoing committed information rate (CIR) for a Frame Relay virtual circuit.
frame-relay policing	Enables Frame Relay policing on all switched PVCs on an interface.
frame-relay switching	Enables PVC switching on a Frame Relay DCE or NNI.

show frame-relay pvc

To display statistics about permanent virtual circuits (PVCs) for Frame Relay interfaces, use the show frame-relay pvc privileged EXEC command.

Congestion control mechanisms are currently not supported on terminated PVCs, but the switch passes forward explicit congestion notification (FECN) bits, backward explicit congestion notification (BECN) bits, and discard eligibility (DE) bits unchanged from entry to exit points in the network.

Router# show frame-relay pvc 200
  
PVC Statistics for interface Serial3/0 (Frame Relay DTE)
  
DLCI = 200, DLCI USAGE = SWITCHED, PVC STATUS = ACTIVE, INTERFACE = Serial3/0
 
  input pkts 341           output pkts 390          in bytes 341000
  out bytes 390000         dropped pkts 0           in FECN pkts 0
  in BECN pkts 0           out FECN pkts 0          out BECN pkts 0
  in DE pkts 0             out DE pkts 390
  out bcast pkts 0          out bcast bytes 0            Num Pkts Switched 341
 
  pvc create time 00:10:35, last time pvc status changed 00:10:06
  Congestion DE threshold 50 
  shaping active 
  cir 56000     bc 7000      be 0         byte limit 875    interval 125
  mincir 28000     byte increment 875   BECN response no
  pkts 346       bytes 346000    pkts delayed 339       bytes delayed 339000
  traffic shaping drops 0
  Queueing strategy:fifo
  Output queue 48/100, 0 drop, 339 dequeued 
 

Router# show frame-relay pvc 100
 
PVC Statistics for interface Serial1/0 (Frame Relay DCE)
 
DLCI = 100, DLCI USAGE = SWITCHED, PVC STATUS = ACTIVE, INTERFACE = Serial1/0  
 
  input pkts 1260          output pkts 0            in bytes 1260000
  out bytes 0              dropped pkts 0           in FECN pkts 0
  in BECN pkts 0           out FECN pkts 0          out BECN pkts 0
  in DE pkts 0             out DE pkts 0
  out bcast pkts 0          out bcast bytes 0            Num Pkts Switched 1260
 
  pvc create time 00:03:57, last time pvc status changed 00:03:19
  policing enabled, 180 pkts marked DE
  policing Bc  6000        policing Be  6000        policing Tc  125 (msec)
  in Bc pkts   1080        in Be pkts   180         in xs pkts   0
  in Bc bytes  1080000     in Be bytes  180000      in xs bytes  0

 Router# show frame-relay pvc 55
 
PVC Statistics for interface Serial5/1 (Frame Relay DTE)
DLCI = 55, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial5/1.1
     input pkts 9             output pkts 16           in bytes 154
     out bytes 338            dropped pkts 6           in FECN pkts 0
     in BECN pkts 0           out FECN pkts 0          out BECN pkts 0
     in DE pkts 0             out DE pkts 0
     out bcast pkts 0         out bcast bytes 0
     pvc create time 00:35:11, last time pvc status changed 00:00:22
     Bound to Virtual-Access1 (up, cloned from Virtual-Template5)
 

interface serial 0
     encapsulation frame-relay
     frame-relay traffic-shaping
     frame-relay interface-dlci 108
       vofr cisco
       class vofr-class
   map-class frame-relay vofr-class
     frame-relay fragment 100
     frame-relay fair-queue
     frame-relay cir 64000
     frame-relay voice bandwidth 25000
Router# show frame-relay pvc 108
PVC Statistics for interface Serial0 (Frame Relay DTE)
DLCI = 108, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial0
  input pkts 1260          output pkts 1271         in bytes 95671     
  out bytes 98604          dropped pkts 0           in FECN pkts 0         
  in BECN pkts 0           out FECN pkts 0          out BECN pkts 0         
  in DE pkts 0             out DE pkts 0         
  out bcast pkts 1271       out bcast bytes 98604     
  pvc create time 09:43:17, last time pvc status changed 09:43:17
  Service type VoFR-cisco
  configured voice bandwidth 25000, used voice bandwidth 0
  voice reserved queues 24, 25
  fragment type VoFR-cisco         fragment size 100
  cir 64000     bc 64000     be 0         limit 1000   interval 125 
  mincir 32000     byte increment 1000  BECN response no 
  pkts 2592      bytes 205140    pkts delayed 1296      bytes delayed 102570   
  shaping inactive    
  shaping drops 0
  Current fair queue configuration:
   Discard     Dynamic      Reserved
   threshold   queue count  queue count
64          16           2    
  Output queue size 0/max total 600/drops 0

interface serial 0
     encapsulation frame-relay
     frame-relay traffic-shaping
     frame-relay interface-dlci 110
       class frag
   map-class frame-relay frag
     frame-relay fragment 100
     frame-relay fair-queue
     frame-relay cir 64000
 
Router# show frame-relay pvc 110
PVC Statistics for interface Serial0 (Frame Relay DTE)
DLCI = 110, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial0
  input pkts 0             output pkts 243          in bytes 0         
  out bytes 7290           dropped pkts 0           in FECN pkts 0         
  in BECN pkts 0           out FECN pkts 0          out BECN pkts 0         
  in DE pkts 0             out DE pkts 0         
  out bcast pkts 243        out bcast bytes 7290      
  pvc create time 04:03:17, last time pvc status changed 04:03:18
  fragment type end-to-end         fragment size 100
  cir 64000     bc 64000     be 0         limit 1000   interval 125 
  mincir 32000     byte increment 1000  BECN response no 
  pkts 486       bytes 14580     pkts delayed 243       bytes delayed 7290     
  shaping inactive    
  shaping drops 0
  Current fair queue configuration:
   Discard     Dynamic      Reserved
   threshold   queue count  queue count
   64          16           2    
  Output queue size 0/max total 600/drops 0
 

Router# show frame-relay pvc
DLCI = 300, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0.103
input pkts 10  output pkts 7  in bytes 6222 
out bytes 6034  dropped pkts 0  in FECN pkts 0 
in BECN pkts 0  out FECN pkts 0  out BECN pkts 0 
in DE pkts 0  out DE pkts 0         
outbcast pkts 0  outbcast bytes 0
pvc create time 0:13:11  last time pvc status changed 0:11:46
DLCI = 400, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0.104
input pkts 20  output pkts 8  in bytes 5624 
out bytes 5222  dropped pkts 0  in FECN pkts 0 
in BECN pkts 0  out FECN pkts 0  out BECN pkts 0 
in DE pkts 0  out DE pkts 0         
outbcast pkts 0  outbcast bytes 0
pvc create time 0:03:57  last time pvc status changed 0:03:48

Router# show frame-relay pvc interface serial 1 45
  
 PVC Statistics for interface Serial1 (Frame Relay DTE)
  
 DLCI = 45, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial1
  
   input pkts 85            output pkts 289          in bytes 1730      
   out bytes 6580           dropped pkts 11          in FECN pkts 0         
   in BECN pkts 0           out FECN pkts 0          out BECN pkts 0         
   in DE pkts 0             out DE pkts 0         
   out bcast pkts 0          out bcast bytes 0         
   pvc create time 00:02:09, last time pvc status changed 00:02:09
   Service type VoFR
   configured voice bandwidth 25000, used voice bandwidth 22000
   fragment type VoFR         fragment size 100
   cir 20000     bc   1000      be 0         limit 125    interval 50  
   mincir 20000     byte increment 125   BECN response no 
   fragments 290       bytes 6613      fragments delayed 1         bytes delayed 33       
   shaping inactive    
   traffic shaping drops 0
    Voice Queueing Stats: 0/100/0 (size/max/dropped)
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   Current fair queue configuration:
    Discard     Dynamic      Reserved
    threshold   queue count  queue count
    64          16           2    
   Output queue size 0/max total 600/drops 0
 

show interfaces serial

To display information about a serial interface, use the show interfaces serial privileged EXEC command. When using the Frame Relay encapsulation, use the show interfaces serial EXEC command to display information about the multicast DLCI, the DLCIs used on the interface, and the DLCI used for the Local Management Interface (LMI).

Cisco 4000 Series

show interfaces serial [number [:channel-group] [accounting]

Cisco 7200 Series

show interfaces serial [slot/port] [accounting]

Cisco 7000 and Cisco 7500 Series with the RSP7000, RSP7000CI, or Ports on VIPs

show interfaces serial [slot/port-adapter/port]

Cisco 7500 Series

show interfaces serial [slot/port [:channel-group]] [accounting]

Cisco 7500 Series with a CT3IP

show interfaces serial [ slot/port-adapter/port] [:t1-channel] [accounting | crb]

Cisco AS5800 Access Servers

show interfaces serial dial-shelf/slot/t3-port:t1-num:chan-group

Syntax Description

number	(Optional) Number of the port being configured.
:channel-group	(Optional) On the Cisco 4000 series with an NPM or Cisco 7500 series routers with a MultiChannel Interface Processor (MIP), specifies the T1 channel-group number in the range of 0 to 23 defined with the channel-group controller configuration command.
accounting	(Optional) Displays the number of packets of each protocol type that have been sent through the interface.
slot	(Optional) Number of the slot being configured. Refer to the appropriate hardware manual for slot and port information.
port	(Optional) Number of the port being configured. Refer to the appropriate hardware manual for slot and port information.
port-adapter	(Optional) Number of the port adapter being configured. Refer to the appropriate hardware manual for information about port adapter compatibility.
:t1-channel	(Optional) For the CT3IP, the T1 channel is a number between 1 and 28. T1 channels on the CT3IP are numbered from 1 to 28 rather than the more traditional zero-based scheme (0 to 27) used with other Cisco products. This is to ensure consistency with telco numbering schemes for T1 channels within channelized T3 equipment.
crb	(Optional) Shows interface routing and bridging information.
dial-shelf	Dial shelf chassis in the Cisco AS5800 access server containing the CT3 interface card.
slot	Location of the CT3 interface card in the dial shelf chassis.
t3-port	T3 port number. The only valid value is 0.
:t1-num	T1 time slot in the T3 line. The value can be from 1 to 28.
chan-group	Channel group identifier.

Defaults

No default behavior or values.

Router# show interface Serial3/0    
Serial3/0 is up, line protocol is up
  Hardware is M4T 
  Description:Connects to Router Serial3/0
  MTU 1500 bytes, BW 2048 Kbit, DLY 20000 usec,
     reliability 255/255, txload 2/255, rxload 2/255
  Encapsulation FRAME-RELAY, crc 16, loopback not set
  Keepalive set (10 sec)
  LMI enq sent  9, LMI stat recvd 9, LMI upd recvd 0, DTE LMI up
  LMI enq recvd 0, LMI stat sent  0, LMI upd sent  0
  LMI DLCI 0  LMI type is ANSI Annex D  frame relay DTE
  FR SVC disabled, LAPF state down 
  Congestion ECN thresholds 0/50 
  Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0
  Last input 00:00:02, output 00:00:00, output hang never
  Last clearing of "show interface" counters 00:01:28
  Queueing strategy:fifo
  Output queue 56/100, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 20000 bits/sec, 7 packets/sec
  5 minute output rate 24000 bits/sec, 7 packets/sec
     622 packets input, 613131 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
     658 packets output, 649126 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up
 

Table 3 describes the output fields unique to Frame Relay congestion management.

Table 3: show interfaces serial Field Descriptions Relevant to Frame Relay Congestion Management

Field	Description
Congestion ECN thresholds	Be ECN threshold (in packets) at which packets are marked with BECN and FECN bits/Bc ECN threshold at which packets are marked with BECN and FECN bits.
Congestion ECN Be threshold	Be ECN threshold (in packets) at which packets are marked with BECN and FECN bits
Congestion DE threshold	PVC queue percentage at which packets marked with the DE bit are dropped.
DE drops	Number of DE bit-marked packets dropped.

Router# show interfaces serial
 
Serial 0 is up, line protocol is up
   Hardware is MCI Serial
   Internet address is 150.136.190.203, subnet mask is 255.255.255.0
   MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
   Encapsulation HDLC, loopback not set, keepalive set (10 sec)
   Last input 0:00:07, output 0:00:00, output hang never
   Output queue 0/40, 0 drops; input queue 0/75, 0 drops
   Five minute input rate 0 bits/sec, 0 packets/sec
   Five minute output rate 0 bits/sec, 0 packets/sec
       16263 packets input, 1347238 bytes, 0 no buffer
       Received 13983 broadcasts, 0 runts, 0 giants
       2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort
1 carrier transitions 
 
     22146 packets output, 2383680 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets, 0 restarts
 

Table 4 describes significant fields shown in the display.

Table 4: show interfaces serial Field Descriptions

Field	Description
Serial ... is {up | down} ... is administratively down	Indicates whether the interface hardware is currently active (whether carrier detect is present), inactive, or has been taken down by an administrator.
line protocol is {up | down}	Indicates whether the software processes that handle the line protocol consider the line usable (that is, whether keepalives are successful) or it has been taken down by an administrator.
Hardware is	Specifies the hardware type.
Internet address is	Specifies the Internet address and subnet mask.
MTU	Maximum transmission unit of the interface.
BW	Indicates the value of the bandwidth parameter that has been configured for the interface (in kilobits per second). The bandwidth parameter is used to compute Interior Gateway Routing Protocol (IGRP) metrics only. If the interface is attached to a serial line with a line speed that does not match the default (1536 or 1544 for T1 and 56 for a standard synchronous serial line), use the bandwidth command to specify the correct line speed for this serial line.
DLY	Delay of the interface in microseconds.
rely	Reliability of the interface as a fraction of 255 (255/255 is 100 percent reliability), calculated as an exponential average over 5 minutes.
load	Load on the interface as a fraction of 255 (255/255 is completely saturated), calculated as an exponential average over 5 minutes.
Encapsulation	Encapsulation method assigned to interface.
loopback	Indicates whether loopback is set or not.
keepalive	Indicates whether keepalives are set or not.
Last input	Number of hours, minutes, and seconds since the last packet was successfully received by an interface. Useful for knowing when a dead interface has failed.
Last output	Number of hours, minutes, and seconds since the last packet was successfully transmitted by an interface.
output hang	Number of hours, minutes, and seconds since the interface was last reset because of a transmission that took too long. When the number of hours in any of the "last" fields exceeds 24 hours, the number of days and hours is printed. If that field overflows, asterisks are printed.
Output queue, drops input queue, drops	Number of packets in output and input queues. Each number is followed by a slash, the maximum size of the queue, and the number of packets dropped because of a full queue.
5 minute input rate 5 minute output rate	Average number of bits and packets transmitted per second in the last 5 minutes. The 5-minute input and output rates should be used only as an approximation of traffic per second during a given 5-minute period. These rates are exponentially weighted averages with a time constant of 5 minutes. A period of four time constants must pass before the average will be within two percent of the instantaneous rate of a uniform stream of traffic over that period.
packets input	Total number of error-free packets received by the system.
bytes	Total number of bytes, including data and MAC encapsulation, in the error-free packets received by the system.
no buffer	Number of received packets discarded because there was no buffer space in the main system. Compare with ignored count. Broadcast storms on Ethernet networks and bursts of noise on serial lines are often responsible for no-input-buffer events.
Received... broadcasts	Total number of broadcast or multicast packets received by the interface.
runts	Number of packets that are discarded because they are smaller than the minimum packet size for the medium.
giants	Number of packets that are discarded because they exceed the maximum packet size for the medium.
input errors	Total number of no-buffer, runts, giants, CRCs, frame, overrun, ignored, and abort counts. Other input-related errors can also increment the count, so this sum might not balance with the other counts.
CRC	Cyclic redundancy checksum generated by the originating station or far-end device does not match the checksum calculated from the data received. On a serial link, CRCs usually indicate noise, gain hits, or other transmission problems on the data link.
frame	Number of packets received incorrectly having a CRC error and a noninteger number of octets. On a serial line, this is usually the result of noise or other transmission problems.
overrun	Number of times the serial receiver hardware was unable to hand received data to a hardware buffer because the input rate exceeded the receiver's ability to handle the data.
ignored	Number of received packets ignored by the interface because the interface hardware ran low on internal buffers. Broadcast storms and bursts of noise can cause the ignored count to be increased.
abort	Illegal sequence of one bits on a serial interface. This usually indicates a clocking problem between the serial interface and the data link equipment.
carrier transitions	Number of times the carrier detect signal of a serial interface has changed state. For example, if data carrier detect (DCD) goes down and comes up, the carrier transition counter will increment two times. Modem or line problems may be present if the carrier detect line is changing state often.
packets output	Total number of messages transmitted by the system.
bytes output	Total number of bytes, including data and MAC encapsulation, transmitted by the system.
underruns	Number of times that the transmitter has been running faster than the router can handle. This might never be reported on some interfaces.
output errors	Sum of all errors that prevented the final transmission of datagrams out of the interface being examined. Note that this might not balance with the sum of the enumerated output errors because some datagrams can have more than one error, and others can have errors that do not fall into any of the specifically tabulated categories.
collisions	Number of messages retransmitted due to an Ethernet collision. This usually is the result of an overextended LAN (Ethernet or transceiver cable too long, more than two repeaters between stations, or too many cascaded multiport transceivers). Some collisions are normal. However, if your collision rate climbs to about 4 or 5 percent, you should consider verifying that there is no faulty equipment on the segment or moving some existing stations to a new segment. A packet that collides is counted only once in output packets.
interface resets	Number of times an interface has been completely reset. This can happen if packets queued for transmission were not sent within several seconds' time. On a serial line, this can be caused by a malfunctioning modem that is not supplying the transmit clock signal, or by a cable problem. If the system notices that the carrier detect line of a serial interface is up, but the line protocol is down, it periodically resets the interface in an effort to restart it. Interface resets can also occur when an interface is looped back or shut down.
restarts	Number of times the controller was restarted because of errors.
alarm indications, remote alarms, rx LOF, rx LOS	Number of channel service unit (CSU)/data service unit (DSU) alarms, and number of occurrences of receive loss of frame and receive loss of signal.
BER inactive, NELR inactive, FELR inactive	Status of G.703-E1 counters for bit-error rate (BER) alarm, near-end loop remote (NELR), and far-end loop remote (FELR). Note that you cannot set the NELR or FELR.

Router# show interfaces serial 3/0/0
 
Serial3/0/0 is up, line protocol is up 
  Hardware is cyBus Serial
  Internet address is 1.0.0.1/8
  MTU 1500 bytes, BW 6312 Kbit, DLY 20000 usec, rely 255/255, load 26/255
  Encapsulation HDLC, loopback not set, keepalive not set
  Last input 00:04:31, output 00:04:31, output hang never
  Last clearing of "show interface" counters 00:06:07
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 162000 bits/sec, 8 packets/sec
  5 minute output rate 162000 bits/sec, 8 packets/sec
     20005 packets input, 20080520 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     20005 packets output, 20080520 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
     0 cv errors, 0 crc5 errors, 0 frame errors
     rxLOS inactive, rxLOF inactive, rxPAIS inactive
     rxAIS inactive, rxRAI inactive, rxHBER inactive
 

Table 5 describes significant fields shown in the display that are different from the fields described in Table 4.

Table 5: show interfaces serial Field Descriptions—PA-2JT2

Field	Description
Last clearing of "show interface" counters	Time the counters were last cleared.
Queueing strategy	First-in, first-out queueing strategy (other queueing strategies you might see are priority-list, custom-list, and weighted fair).
output buffer failures	Number of no-resource errors received on the output.
output buffers swapped out	Number of packets swapped to dynamic random-access memory (DRAM).
carrier transitions	Number of times the carrier detect signal of a serial interface has changed state. For example, if data carrier detect (DCD) goes down and comes up, the carrier transition counter will increment two times. Modem or line problems may be present if the carrier detect line is changing state often.
cv errors	B8ZS/B6ZS (zero suppression) coding violation counter.
crc5 errors	CRC-5 error counter.
frame errors	Framing error counter.
rx LOS	Receive loss of signal alarm. Value is active or inactive.
rxLOF	Receive loss of frame alarm. Value is active or inactive.
rxPAIS	Receive loss of payload alarm indication signal (AIS). Value is active or inactive.
rxAIS	Receive loss of physical AIS. Value is active or inactive.
rxRAI	Receive remote AIS. Value is active or inactive.
rxHBER	Receive high bit-error rate alarm. Value is active or inactive.

Router# show interfaces serial 2/0
 
Serial2/0 is up, line protocol is up
  Hardware is M1T-E3 pa
  Internet address is 131.1.1.1/24
  MTU 4470 bytes, BW 34010 Kbit, DLY 200 usec, rely 128/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive not set
  Last input 1w0d, output 00:00:48, output hang never
  Last clearing of "show interface" counters 1w0d
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     20 packets input, 2080 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 parity
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     11472 packets output, 3824748 bytes, 0 underruns
     0 output errors, 0 applique, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
   rxLOS inactive, rxLOF inactive, rxAIS inactive
   txAIS inactive, rxRAI inactive, txRAI inactive
 

Table 6 describes significant fields shown in the display that are different from the fields described in Table 4.

Table 6: show interfaces serial Field Descriptions—PA-E3

Field	Description
Last clearing of "show interface" counters	Time the counters were last cleared.
Queueing strategy	First-in, first-out queueing strategy (other queueing strategies you might see are priority-list, custom-list, and weighted fair).
parity	Number of the parity errors on the interface.
applique	Indicates that an unrecoverable error has occurred on the E3 applique. The router then invokes an interface reset.
output buffer failures	Number of no-resource errors received on the output.
output buffers swapped out	Number of packets swapped to DRAM.
rxLOS, rxLOF, rxAIS	Receive loss of signal, loss of frame, and alarm indication signal status. Value is inactive or active.
txAIS, rxRAI, txRAI	Transmit alarm indication signal, receive remote alarm indicator, and transmit remote alarm indicator status. Value is inactive or active. When the router receives an LOS, LOF, or AIS, the txRAI is active. When the remote router receives an LOS, LOF, or AIS, the rxRAI is active.

Router# show interfaces serial 1/0/0
 
Serial1/0/0 is up, line protocol is up
  Hardware is cyBus PODS3 Serial
  Internet address is 133.1.1.1/24
  MTU 4470 bytes, BW 44736 Kbit, DLY 200 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input 00:00:05, output 00:00:02, output hang never
  Last clearing of "show interface" counters 5d02h
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 27269 drops
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     79039 packets input, 14195344 bytes, 0 no buffer
     Received 84506 broadcasts, 0 runts, 0 giants
              0 parity
     9574 input errors, 6714 CRC, 0 frame, 1 overrun, 0 ignored, 2859 abort
     62472 packets output, 13751644 bytes, 0 underruns
     0 output errors, 0 applique, 10 interface resets
     0 output buffer failures, 0 output buffers swapped out
     16 carrier transitions
   rxLOS inactive, rxLOF inactive, rxAIS inactive
   txAIS inactive, rxRAI inactive, txRAI inactive
 

Table 7 describes significant fields shown in the display that are different from the fields described in Table 4.

Table 7: show interfaces serial Field Descriptions—PA-T3

Field	Description
Last clearing of "show interface" counters	Time the counters were last cleared.
Queueing strategy	First-in, first-out queueing strategy (other queueing strategies you might see are priority-list, custom-list, and weighted fair).
parity	Number of the parity errors on the interface.
applique	Indicates an unrecoverable error has occurred on the T3 applique. The router then invokes an interface reset.
output buffer failures	Number of no resource errors received on the output.
output buffers swapped out	Number of packets swapped to DRAM.
rxLOS, rxLOF, rxAIS	Receive loss of signal, loss of frame, and alarm indication signal status. Values are inactive or active.
txAIS, rxRAI, txRAI	Transmit alarm indication signal, receive remote alarm indicator, and transmit remote alarm indicator status. Values are inactive or active. When the router receives an LOS, LOF, or AIS, the txRAI is active. When the remote router receives an LOS, LOF, or AIS, the rxRAI is active.

The following is sample output of the show interfaces serial command for the CT3IP serial interface:

Router# show interfaces serial 3/0/0:25
 
Serial3/0/0:25 is up, line protocol is up 
  Hardware is cyBus T3
  Internet address is 25.25.25.2/24
  MTU 1500 bytes, BW 1536 Kbit, DLY 20000 usec, rely 255/255, load 12/255
  Encapsulation HDLC, loopback not set, keepalive not set
  Last input 00:19:01, output 00:11:49, output hang never
  Last clearing of "show interface" counters 00:19:39
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/64/0 (size/threshold/drops) 
     Conversations 0/1 (active/max active)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 69000 bits/sec, 90 packets/sec
  5 minute output rate 71000 bits/sec, 90 packets/sec
     762350 packets input, 79284400 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants
     150 input errors, 0 CRC, 0 frame, 150 overrun, 0 ignored, 0 abort
     763213 packets output, 80900472 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions no alarm present
  Timeslot(s) Used:1-24, Transmitter delay is 0 flags, transmit queue length 5
  non-inverted data
 

Most fields are described in Table 4. Fields relevant to the CT3IP are described in Table 8.

Table 8: show interfaces serial Field Descriptions—CT3IP

Field	Description
Timeslot(s) Used	Number of time slots assigned to the T1 channel.
Transmitter delay	Number of idle flags inserted between HDLC frames.
transmit queue length	Number of packets allowed in the transmit queue.
non-inverted data	Indicates whether or not the interface is configured for inverted data.

Router# show interfaces serial 1/0
 
Serial1/0 is up, line protocol is up
  Hardware is cxBus Serial
  Internet address is 150.136.190.203, subnet mask is 255.255.255.0
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input 0:00:07, output 0:00:00, output hang never
  Last clearing of "show interface" counters 2w4d
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  Five minute input rate 0 bits/sec, 0 packets/sec
  Five minute output rate 0 bits/sec, 0 packets/sec
     16263 packets input, 1347238 bytes, 0 no buffer
     Received 13983 broadcasts, 0 runts, 0 giants
     2 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort
     22146 packets output, 2383680 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets, 0 restarts
     1 carrier transitions 
 

Router# show interfaces serial 2/3
Serial2/3 is up, line protocol is up
  Hardware is cxBus Serial
  Internet address is 5.4.4.1, subnet mask is 255.255.255.0
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive not set
  Last input 0:00:21, output 0:00:21, output hang never
  Last clearing of "show interface" counters never
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  Five minute input rate 0 bits/sec, 0 packets/sec
  Five minute output rate 0 bits/sec, 0 packets/sec
     53 packets input, 7810 bytes, 0 no buffer
     Received 53 broadcasts, 0 runts, 0 giants
     2 input errors, 2 CRC, 0 frame, 0 overrun, 0 ignored, 2 abort
     56 packets output, 8218 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets, 0 restarts
     1 carrier transitions
     2 alarm indications, 333 remote alarms, 332 rx LOF, 0 rx LOS
     RTS up, CTS up, DTR up, DCD up, DSR up
     BER inactive, NELR inactive, FELR inactive
 

Table 4 describes fields shown in the display.

Example with Frame Relay Encapsulation

When using the Frame Relay encapsulation, use the show interfaces command to display information on the multicast DLCI, the DLCI of the interface, and the LMI DLCI used for the local management interface.

The multicast DLCI and the local DLCI can be set using the frame-relay multicast-dlci and the frame-relay local-dlci configuration commands or provided through the local management interface. The status information is taken from the LMI, when active.

The following is sample output from the show interfaces serial command when Frame Relay encapsulation and LMI is enabled:

Router# show interfaces serial
 
Serial 2 is up, line protocol is up
   Hardware type is MCI Serial
   Internet address is 131.108.122.1, subnet mask is 255.255.255.0
   MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
   Encapsulation FRAME-RELAY, loopback not set, keepalive set (10 sec)
   multicast DLCI 1022, status defined, active
   source DLCI    20, status defined, active
   LMI DLCI 1023, LMI sent 10, LMI stat recvd 10, LMI upd recvd 2
   Last input 7:21:29, output 0:00:37, output hang never
   Output queue 0/100, 0 drops; input queue 0/75, 0 drops
   Five minute input rate 0 bits/sec, 0 packets/sec
   Five minute output rate 0 bits/sec, 0 packets/sec
       47 packets input, 2656 bytes, 0 no buffer
       Received 5 broadcasts, 0 runts, 0 giants
       5 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 57 abort
       518 packets output, 391205 bytes
       0 output errors, 0 collisions, 0 interface resets, 0 restarts
       1 carrier transitions
 

In this display, the multicast DLCI has been changed to 1022 with the frame-relay multicast-dlci interface configuration command.

The display shows the statistics for the LMI as the number of status inquiry messages sent (LMI sent), the number of status messages received (LMI recvd), and the number of status updates received (upd recvd). See the Frame Relay Interface specification for additional explanations of this output.

Example with ANSI LMI

For a serial interface with the ANSI LMI enabled, use the show interfaces serial command to determine the LMI type implemented.

The following is an example from the show interfaces serial output for a serial interface with the ANSI LMI enabled:

Router# show interfaces serial
 
Serial 1 is up, line protocol is up
   Hardware is MCI Serial
   Internet address is 131.108.121.1, subnet mask is 255.255.255.0
   MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
   Encapsulation FRAME-RELAY, loopback not set, keepalive set
   LMI DLCI    0, LMI sent 10, LMI stat recvd 10
   LMI type is ANSI Annex D
   Last input 0:00:00, output 0:00:00, output hang never
   Output queue 0/40, 0 drops; input queue 0/75, 0 drops

   Five minute input rate 0 bits/sec, 1 packets/sec
   Five minute output rate 1000 bits/sec, 1 packets/sec
       261 packets input, 13212 bytes, 0 no buffer
       Received 33 broadcasts, 0 runts, 0 giants
       0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
       238 packets output, 14751 bytes, 0 underruns
       0 output errors, 0 collisions, 0 interface resets, 0 restarts
 

Notice that the show interfaces serial output for a serial interface with ANSI LMI shown in this display is very similar to that for encapsulation set to Frame Relay, as shown in the previous display. Table 9 describes the few differences that exist.

Table 9: show interfaces serial Field Description—with ANSI LMI

Field	Description
LMI DLCI 0	Identifies the DLCI used by the LMI for this interface. The default is 1023.
LMI sent 10	Number of LMI packets sent by the router.
LMI type is ANSI Annex D	Indicates that the interface is configured for the ANSI-adopted Frame Relay specification T1.617 Annex D.

Router# show interfaces serial 1
 
LAPB state is SABMSENT, T1 3000, N1 12056, N2 20, k7,Protocol ip
VS 0, VR 0, RCNT 0, Remote VR 0, Retransmissions 2
IFRAMEs 0/0 RNRs 0/0 REJs 0/0 SABMs 3/0 FRMRs 0/0 DISCs 0/0
 

Table 10 shows the fields relevant to all LAPB connections.

Show Interfaces Serial with PPP

An interface configured for synchronous PPP encapsulation differs from the standard show interfaces serial output. An interface configured for PPP might include the following information:

  lcp state = OPEN
  ncp ipcp state = OPEN   ncp osicp state = NOT NEGOTIATED
  ncp ipxcp state = NOT NEGOTIATED   ncp xnscp state = NOT NEGOTIATED
  ncp vinescp state = NOT NEGOTIATED   ncp deccp state = NOT NEGOTIATED
  ncp bridgecp state = NOT NEGOTIATED   ncp atalkcp state = NOT NEGOTIATED
 

Table 11 show the fields relevant to PPP connections.

Table 11: show interfaces serial Field Descriptions—with PPP Encapsulation

Field	Description
lcp state	Link Control Protocol.
ncp ipcp state	Network Control Protocol Internet Protocol Control Protocol.
ncp osicp state	Network Control Protocol OSI (CLNS) Control Protocol.
ncp ipxcp state	Network Control Protocol IPX (Novell) Control Protocol.
ncp xnscp state	Network Control Protocol XNS Control Protocol.
ncp vinescp state	Network Control Protocol VINES Control Protocol.
ncp deccp state	Network Control Protocol DECnet Control Protocol.
ncp bridgecp state	Network Control Protocol Bridging Control Protocol.
ncp atalkcp state	Network Control Protocol AppleTalk Control Protocol.

Use the show interfaces command to display the Synchronous Data Link Control (SDLC) information for a given SDLC interface. The following is sample output from the show interfaces command for an SDLC primary interface supporting the SDLLC function:

Router# show interfaces
 
Serial 0 is up, line protocol is up
Hardware is MCI Serial
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation SDLC-PRIMARY, loopback not set
    Timers (msec): poll pause 100 fair poll 500. Poll limit 1
    [T1 3000, N1 12016, N2 20, K 7] timer: 56608 Last polled device: none
    SDLLC [ma: 0000.0C01.14--, ring: 7 bridge: 1, target ring: 10
             largest token ring frame 2052]
SDLC addr C1 state is CONNECT
     VS 6, VR 3, RCNT 0, Remote VR 6, Current retransmit count 0
     Hold queue: 0/12 IFRAMEs 77/22 RNRs 0/0 SNRMs 1/0 DISCs 0/0
     Poll: clear, Poll count: 0, chain: p: C1 n: C1
     SDLLC [largest SDLC frame: 265, XID: disabled]
 Last input 00:00:02, output 00:00:01, output hang never
 Output queue 0/40, 0 drops; input queue 0/75, 0 drops
 Five minute input rate 517 bits/sec, 30 packets/sec
 Five minute output rate 672 bits/sec, 20 packets/sec
     357 packets input, 28382 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     926 packets output, 77274 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets, 0 restarts
     2 carrier transitions
 

Table 12 shows the fields relevant to all SDLC connections.

Table 12: show interfaces serial Field Descriptions—with SDLC Enabled

Field	Description
Timers (msec): poll pause, fair poll, Poll limit	Current values of these timers, as described in the configuration section, for this interface.
T1, N1, N2, K	Values for these parameters, as described in the configuration section, for this interface.

Table 13 shows other data given for each SDLC secondary interface configured to be attached to this interface.

Table 13: SDLC Secondary Interface Descriptions

SDLC Secondary	Description
addr	Address of this secondary.
state is	Current state of this connection, which is one of the following: DISCONNECT—No communication is being attempted to this secondary. CONNECT—A normal connect state exists between this router and this secondary. DISCSENT—This router has sent a disconnect request to this secondary and is awaiting its response. SNRMSENT—This router has sent a connect request (SNRM) to this secondary and is awaiting its response. THEMBUSY—This secondary has told this router that it is temporarily unable to receive any more information frames. USBUSY—This router has told this secondary that it is temporarily unable to receive any more information frames. BOTHBUSY—Both sides have told each other that they are temporarily unable to receive any more information frames. ERROR—This router has detected an error and is waiting for a response from the secondary acknowledging this.
VS	Sequence number of the next information frame sent by this station.
VR	Sequence number of the next information frame from this secondary that this station expects to receive.
Remote VR	Last frame transmitted by this station that has been acknowledged by the other station.
Current retransmit count:	Number of times the current I-frame or sequence of I-frames has been retransmitted.
Hold Queue	Number of frames in hold queue/maximum size of hold queue.
IFRAMEs, RNRs, SNRMs, DISCs	Sent/received count for these frames.
Poll	"Set" if this router has a poll outstanding to the secondary; "clear" if it does not.
Poll Count	Number of polls in a row that have been given to this secondary at this time.
Chain	Shows the previous (p) and next (n) secondary address on this interface in the round robin loop of polled devices.

Router# show interfaces serial
 
Serial 0 is up, line protocol is up
   Hardware is MCI Serial
   MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
   Encapsulation SDLC-PRIMARY, loopback not set
       Timers (msec): poll pause 100 fair poll 500. Poll limit 1
       [T1 3000, N1 12016, N2 20, K 7] timer: 56608 Last polled device: none
       SDLLC [ma: 0000.0C01.14--, ring: 7 bridge: 1, target ring: 10
             largest token ring frame 2052]
   SDLC addr C1 state is CONNECT
       VS 6, VR 3, RCNT 0, Remote VR 6, Current retransmit count 0
       Hold queue: 0/12 IFRAMEs 77/22 RNRs 0/0 SNRMs 1/0 DISCs 0/0
       Poll: clear, Poll count: 0, chain: p: C1 n: C1
       SDLLC [largest SDLC frame: 265, XID: disabled]
   Last input 00:00:02, output 00:00:01, output hang never
   Output queue 0/40, 0 drops; input queue 0/75, 0 drops
   Five minute input rate 517 bits/sec, 30 packets/sec
   Five minute output rate 672 bits/sec, 20 packets/sec
       357 packets input, 28382 bytes, 0 no buffer
       Received 0 broadcasts, 0 runts, 0 giants
       0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
       926 packets output, 77274 bytes, 0 underruns
       0 output errors, 0 collisions, 0 interface resets, 0 restarts
       6608 Last polled device: none
       SDLLC [ma: 0000.0C01.14--, ring: 7 brid2 carrier transitions 

Most of the output shown in the display is generic to all SDLC encapsulated interfaces and is described in the "LLC2 and SDLC Commands" chapter in the Cisco IOS Bridging and IBM Networking Command Reference. Table 14 shows the parameters specific to SDLLC.

Table 14: SDLLC Parameter Descriptions

Field	Description
SDLLC ma	Lists the MAC address configured for this interface. The last byte is shown as "--" to indicate that it is filled in with the SDLC address of the connection.
ring, bridge, target ring	Lists the parameters as configured by the sdllc traddr command.
largest token ring frame	Shows the largest Token Ring frame that is accepted on the LLC2 side of the connection.
largest SDLC frame	Shows the largest SDLC frame that is accepted and will be generated on the SDLC side of the connection.
XID	Enabled or disabled: Shows whether XID processing is enabled on the SDLC side of the connection. If enabled, it will show the XID value for this address.

The following is a partial sample output from the show interfaces serial command for a serial X.25 interface:

Router# show interfaces serial 1
 
X25 address 000000010100, state R1, modulo 8, idle 0, timer 0, nvc 1
  Window size: input 2, output 2, Packet size: input 128, output 128
  Timers: T20 180, T21 200, T22 180, T23 180, TH 0
  Channels: Incoming-only none, Two-way 1-1024, Outgoing-only none
(configuration on RESTART: modulo 8,
  Window size: input 2 output 2, Packet size: input 128, output 128
  Channels: Incoming-only none, Two-way 5-1024, Outgoing-only none)
  RESTARTs 3/2 CALLs 1000+2/1294+190/0+0/ DIAGs 0/0
 

Table 15 describes significant fields shown in the display.

Table 15: show interfaces serial Field Descriptions—with X.25 Enabled

Field	Description
X25 address 000000010100	Address used to originate and accept calls.
state R1	State of the interface. Possible values are R1—the normal ready state R2—the DTE restarting state R3—the DCE restarting state If the state is R2 or R3, the interface is awaiting acknowledgment of a Restart packet.
modulo 8	Modulo value; determines the packet sequence numbering scheme used.
idle 0	Number of minutes for which the Cisco IOS software waits before closing idle virtual circuits that it originated or accepted.
timer 0	Value of the interface timer, which is zero unless the interface state is R2 or R3.
nvc 1	Default maximum number of simultaneous virtual circuits permitted to and from a single host for a particular protocol.
Window size: input 2, output 2	Default window sizes (in packets) for the interface. The x25 facility interface configuration command can be used to override these default values for the switched virtual circuits originated by the router.
Packet size: input 128, output 128	Default maximum packet sizes (in bytes) for the interface. The x25 facility interface configuration command can be used to override these default values for the switched virtual circuits originated by the router.
Timers: T20 180, T21 200, T22 180, T23 180	Values of the X.25 timers: T10 through T13 for a DCE device T20 through T23 for a DTE device
TH0	Packet acknowledgment threshold (in packets). This value determines how many packets are received before an explicit acknowledgment is sent. The default value (0) sends an explicit acknowledgment only when the incoming window is full.
Channels: Incoming-only none Two-way 5-1024 Outgoing-only none	Displays the virtual circuit ranges for this interface.
RESTARTs 3/2	Shows Restart packet statistics for the interface using the format Sent/Received.
CALLs 1000+2/1294+190/0+0	Successful calls sent + failed calls/calls received + calls failed/calls forwarded + calls failed. Calls forwarded are counted as calls sent.
DIAGs 0/0	Diagnostic messages sent and received.

Router# show interfaces serial 1/0 accounting
 
Serial1/0
       Protocol    Pkts In   Chars In   Pkts Out  Chars Out
             IP       7344    4787842       1803    1535774
      Appletalk      33345    4797459      12781    1089695
        DEC MOP          0          0        127       9779
            ARP          7        420         39       2340
 

Router# show interfaces serial 1/4/0:2:23
Serial1/4/0:2:23 is up, line protocol is up (spoofing)
 Hardware is DS-T1
 MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255
 Encapsulation HDLC, loopback not set
 Last input 00:00:01, output 00:00:01, output hang never
 Last clearing of "show interface" counters 22:24:30
 Queueing strategy: fifo
 Output queue 0/40, 0 drops; input queue 0/75, 0 drops
 5 minute input rate 0 bits/sec, 0 packets/sec

 5 minute output rate 0 bits/sec, 0 packets/sec
     5274 packets input, 20122 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
     5274 packets output, 30836 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     2 carrier transitions no alarm present
 Timeslot(s) Used:24, subrate: 64Kb/s, transmit delay is 0 flags
Router#

Table 16 describes the fields shown in the show interfaces serial display that are different from the fields described in Table 4.

Table 16: show interfaces serial Field Descriptions

Field	Description
Last clearing of "show interface" counters	Time at which the counters that measure cumulative statistics (such as number of bytes transmitted and received) were last reset to zero.
Queueing strategy	Displays the type of queueing configured for this interface. In the example output, the type of queueing configured is first-in, first-out (FIFO).
throttles	Number of times the receiver on the port was disabled, possibly because of buffer or processor overload.
output buffer failures	Number of times the output buffer has failed.
output buffer swapped out	Number of times the output buffer has been swapped out.
Timeslot(s) Used	Number of time slots assigned to the T1 channel.
subrate	Bandwidth of each time slot.
transmit delay is ...	Number of idle flags inserted between frames.

threshold de

To configure the threshold at which DE-marked packets will be discarded from switched PVCs on the output interface, use the threshold de Frame Relay congestion management command. To reconfigure the threshold, use the no form of this command.

Syntax Description

percentage

Threshold at which DE-marked packets will be discarded, specified as a percentage of maximum queue size.

Defaults

100%.

Command Modes

Frame Relay congestion management configuration

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

You must enable Frame Relay congestion management on the interface before congestion management parameters will be effective. To enable Frame Relay congestion management and to enter Frame Relay congestion management configuration mode, use the frame-relay congestion-management interface command.

You must enable Frame Relay switching, using the frame-relay switching global command, before the threshold de command will be effective on switched PVCs.

Examples

The following example shows how to configure a DE threshold of 40% on serial interface 1.

interface serial1
    encapsulation frame-relay
    frame-relay congestion-management
      threshold de 40
 

Related Commands

Command	Description
frame-relay congestion management	Enables Frame Relay congestion management functions on all switched PVCs on an interface, and enters congestion management configuration mode.
frame-relay congestion threshold de	Configures the threshold at which DE-marked packets will be discarded from the traffic-shaping queue of a switched PVC.
frame-relay congestion threshold ecn	Configures the threshold at which ECN bits will be set on packets in the traffic-shaping queue of a switched PVC.
frame-relay switching	Enables PVC switching on a Frame Relay DCE or NNI.
threshold ecn	Configures the threshold at which ECN bits will be set on packets in switched PVCs on the output interface.

threshold ecn

To configure the threshold at which ECN bits will be set on packets in switched PVCs on the output interface, use the threshold ecn Frame Relay congestion management command. To reconfigure the threshold, use the no form of this command.

Syntax Description

bc	Specifies threshold for committed traffic.
be	Specifies threshold for excess traffic.
percentage	Threshold at which ECN bits will be set on packets, specified as a percentage of maximum queue size.

Defaults

100%

Command Modes

Frame Relay congestion management

Command History

Release	Modification
12.1(2)T	This command was introduced.

Usage Guidelines

You must enable Frame Relay congestion management on the interface before congestion management parameters will be effective. To enable Frame Relay congestion management and to enter Frame Relay congestion management configuration mode, use the frame-relay congestion-management interface command.

You must enable Frame Relay switching, using the frame-relay switching global command, before the threshold ecn command will be effective on switched PVCs.

You can configure separate queue thresholds for committed and excess traffic.

Configure the Be ECN threshold so that it is greater than or equal to zero and less than or equal to the Bc ECN threshold. Configure the Bc ECN threshold so that it is less than or equal to 100.

Examples

The following example shows how to configure a Be threshold of 0 and a Bc threshold of 20% on serial interface 1.

interface serial1
    encapsulation frame-relay
    frame-relay congestion-management
      threshold ecn be 0
      threshold ecn bc 20
 

Related Commands

Command	Description
frame-relay congestion management	Enables Frame Relay congestion management functions on all switched PVCs on an interface, and enters congestion management configuration mode.
frame-relay congestion threshold de	Configures the threshold at which DE-marked packets will be discarded from the traffic-shaping queue of a switched PVC.
frame-relay congestion threshold ecn	Configures the threshold at which ECN bits will be set on packets in the traffic-shaping queue of a switched PVC.
frame-relay switching	Enables PVC switching on a Frame Relay DCE or NNI.
threshold de	Configures the threshold at which DE-marked packets will be discarded from switched PVCs on the output interface.

Glossary

BECN—backward explicit congestion notification. Bit set by a Frame Relay network in frames traveling in the opposite direction of frames encountering a congested path. Data terminal equipment (DTE) receiving frames with the BECN bit can request that higher-level protocols take flow-control action as appropriate.

CIR—committed information rate. Rate at which a Frame Relay network agrees to transfer information under normal conditions, averaged over a minimum increment of time.

DCE—data circuit-terminating equipment. Devices and connections of a communications network that make up the network end of the user-to-network interface. The DCE provides a physical connection to the network, forwards traffic, and provides a clocking signal used to synchronize data transmission between DCE and DTE devices.

DE—discard eligible. If the network is congested, DE traffic may be dropped to ensure delivery of higher priority traffic.

DLCI—data-link connection identifier. Value that specifies a permanent virtual circuit (PVC) or switched virtual circuit (SVC) in a Frame Relay network.

FECN—forward explicit congestion notification. Bit set by a Frame Relay network to inform DTE receiving the frame that congestion was experienced in the path from source to the destination. DTE receiving frames with the FECN bit can request that higher-level protocols take flow-control action as appropriate.

FIFO queueing— First-in, first-out queueing. FIFO involves buffering and forwarding of packets in the order of arrival. FIFO embodies no concept of priority or classes of traffic. There is only one queue, and all packets are treated equally. Packets are sent out an interface in the order in which they arrive.

FRF.12—The FRF.12 Implementation Agreement was developed to allow long data frames to be fragmented into smaller pieces and interleaved with real-time frames. In this way, real-time voice and non-real-time data frames can be carried together on lower-speed links without causing excessive delay to the real-time traffic.

FRTS—Frame Relay Traffic Shaping. FRTS uses queues on a Frame Relay network to limit surges that can cause congestion. Data is buffered and then sent into the network in regulated amounts to ensure that the traffic will fit within the promised traffic envelope for the particular connection.

LMI—Local Management Interface. Set of enhancements to the basic Frame Relay specification. LMI includes support for a keepalive mechanism, a multicast mechanism, global addressing, and a status mechanism.

UNI—User-Network Interface. ATM Forum specification that defines an interoperability standard for the interface between ATM-based products located in a private network and the switches located within the public carrier networks. Also used to describe similar connections in Frame Relay networks.

VoFR—Voice over Frame Relay. Enables a router to carry voice traffic over a Frame Relay network. When sending voice traffic over Frame Relay, the voice traffic is segmented and encapsulated for transit across the Frame Relay network using FRF.12 encapsulation.

Voice over Frame Relay—See VoFR.

WFQ—weighted fair queueing. Congestion management algorithm that identifies conversations (in the form of traffic streams), separates packets that belong to each conversation, and ensures that capacity is shared fairly among these individual conversations. WFQ is an automatic way of stabilizing network behavior during congestion and results in increased performance and reduced retransmission.

Posted: Tue Sep 12 09:36:46 PDT 2000
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