Guest

Cisco IOS Software Releases 12.1 T

Frame Relay PVC Interface Priority Queueing

Table Of Contents

Frame Relay PVC Interface Priority Queueing

Feature Overview

Benefits

Restrictions

Related Features and Technologies

Related Documents

Supported Platforms

Supported Standards, MIBs, and RFCs

Prerequisites

Configuration Tasks

Configuring PVC Priority in a Map Class

Enabling FR PIPQ and Setting Queue Limits

Assigning a Map Class to a PVC

Verifying FR PIPQ

Monitoring and Maintaining FR PIPQ

Configuration Examples

FR PIPQ Configuration Example

Command Reference

frame-relay interface-queue priority

show frame-relay pvc

show interfaces

show queueing

Debug Commands

debug priority

Glossary


Frame Relay PVC Interface Priority Queueing


This feature module describes the Frame Relay PVC Interface Priority Queueing (FR PIPQ) 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 FR PIPQ

Configuration Examples

Command Reference

Debug Commands

Glossary

Feature Overview

The FR PIPQ feature provides an interface-level priority queueing scheme in which prioritization is based on destination permanent virtual circuit (PVC) rather than packet contents. For example, FR PIPQ allows you to configure a PVC transporting voice traffic to have absolute priority over a PVC transporting signalling traffic, and a PVC transporting signalling traffic to have absolute priority over a PVC transporting data.

FR PIPQ provides four levels of priority: high, medium, normal, and low. The Frame Relay packet is examined at the interface for the data-link connection identifier (DLCI) value. The packet is then sent to the correct priority queue based on the priority level configured for that DLCI.


Note When using FR PIPQ, configure the network so that different types of traffic are transported on separate PVCs. FR PIPQ is not meant to be used when an individual PVC carries different traffic types that have different quality of service (QoS) requirements.


You assign priority to a PVC within a Frame Relay map class. All PVCs using or inheriting that map class will be classed according to the configured priority. If a PVC does not have a map class associated with it, or if the map class associated with it does not have priority explicitly configured, then the packets on that PVC will be queued on the default "normal" priority queue.

If you do not enable FR PIPQ on the interface using the frame-relay interface-queue priority command in interface configuration mode, configuring PVC priority within a map class will not be effective. At this time you have the option to also set the size (in maximum number of packets) of the four priority queues.

FR PIPQ works with or without Frame Relay traffic shaping (FRTS) and FRF.12. The interface-level priority queueing takes the place of the FIFO queueing or dual FIFO queueing normally used by FRTS and FRF.12. PVC priority assigned within FR PIPQ takes precedence over FRF.12 priority, which means that all packets destined for the same PVC will be queued on the same interface queue whether they were fragmented or not.


Note Although high priority PVCs most likely will transport only small packets of voice traffic, you may want to configure FRF.12 on these PVCs anyway to guard against any unexpectedly large packets.


Benefits

FR PIPQ provides four levels of PVC priority: high, medium, normal, and low. This method of queueing ensures that time/delay-sensitive traffic such as voice has absolute priority over signalling traffic, and that signalling traffic has absolute priority over data traffic, providing different PVCs are used for the different types of traffic.

Restrictions

The following restrictions apply to FR PIPQ:

FR PIPQ is not supported on loopback or tunnel interfaces, or interfaces that explicitly disallow priority queueing.

FR PIPQ is not supported with hardware compression.

FR PIPQ cannot be enabled on an interface that is already configured with queueing other than FIFO queueing. FR PIPQ can be enabled if WFQ is configured, as long as WFQ is the default interface queueing method.

Related Features and Technologies

The following features and technologies are related to FR PIPQ:

FRTS

FRF.12

Related Documents

The following documents provide information related to FR PIPQ:

Cisco IOS Wide-Area Networking Configuration Guide, Release 12.1

Cisco IOS Wide-Area Networking Command Reference, Release 12.1

Supported Platforms

Cisco 1000 series

Cisco 1400 series

Cisco 1600

Cisco 1700

Cisco 1750

Cisco 2500

Cisco 2600

Cisco 3600

Cisco 3810

Cisco 4500

Cisco 4700

Cisco 7200

Cisco 7500 (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 CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

RFCs

No new or modified standards are supported by this feature.

Prerequisites

The following prerequisites apply to FR PIPQ:

PVCs should be configured to carry a single type of traffic.

The network should be configured with adequate call admission control to prevent starvation of any of the priority queues.

Configuration Tasks

See the following sections for configuration tasks for the FR PIPQ feature. Each task in the list is identified as either optional or required:

Configuring PVC Priority in a Map Class (Required)

Enabling FR PIPQ and Setting Queue Limits (Required)

Assigning a Map Class to a PVC (Required)

Configuring PVC Priority in a Map Class

To configure PVC priority within a map class, use the following commands beginning in global configuration mode:

 
Command
Purpose

Step 1 

Router(config)# map-class frame-relay map-class-name

Specifies a Frame Relay map class.

Step 2 

Router(config-map-class)# frame-relay interface-queue priority {high | medium | normal | low}

Assigns a PVC priority level to a Frame Relay map class.

Enabling FR PIPQ and Setting Queue Limits

To enable FR PIPQ and set the priority queue sizes, use the following commands beginning in global configuration mode:

 
Command
Purpose

Step 1 

Router(config)# interface type number [name-tag]

Configures an interface type and enters interface configuration mode.

Step 2 

Router(config-if)# encapsulation frame-relay [cisco | ietf]

Enables Frame Relay encapsulation.

Step 3 

Router(config-if)# frame-relay interface-queue priority [high-limit medium-limit normal-limit low-limit]

Enables FR PIPQ and sets the priority queue limits.

Assigning a Map Class to a PVC

To assign a map class to a specific PVC, use the following commands beginning in interface configuration mode:

 
Command
Purpose

Step 1 

Router(config-if)# frame-relay interface-dlci dlci

Specifies a single PVC on a Frame Relay interface.

Step 2 

Router(config-fr-dlci)# class map-class-name

Associates a map class with a specified PVC.

Verifying FR PIPQ

To verify the configuration of FR PIPQ, use one or more of the following commands in privileged EXEC mode:

Command
Purpose

Router# show frame-relay pvc [interface interface][dlci]

Displays statistics about PVCs for Frame Relay interfaces.

Router# show interfaces [type number][first][last]

Displays the statistical information specific to a serial interface.

Router# show queueing [custom | fair | priority | random-detect [interface atm_subinterface [vc [[vpi/] vci]]]]


Lists all or selected configured queueing strategies.


Monitoring and Maintaining FR PIPQ

To monitor and maintain FR PIPQ, use one or more of the following commands in privileged EXEC mode:

Command
Purpose

Router# debug priority

Debugs priority output queueing.

Router# show frame-relay pvc [interface interface][dlci]

Displays statistics about PVCs for Frame Relay interfaces.

Router# show interfaces [type number][first][last]

Displays the statistical information specific to a serial interface.

Router# show queue interface-name interface-number [vc [vpi/] vci][queue-number]

Displays the contents of packets inside a queue for a particular interface or VC.

Router# show queueing [custom | fair | priority | random-detect [interface atm_subinterface [vc [[vpi/] vci]]]]

Lists all or selected configured queueing strategies.


Configuration Examples

This section provides configuration examples for FR PIPQ.

FR PIPQ Configuration Example

This example shows the configuration of four PVCs on serial interface 0. DLCI 100 is assigned high priority, DLCI 200 is assigned medium priority, DLCI 300 is assigned normal priority, and DLCI 400 is assigned low priority.

The following commands configure Frame Relay map classes with PVC priority levels:

Router(config)# map-class frame-relay HI
Router(config-map-class)# frame-relay interface-queue priority high
Router(config-map-class)# exit
Router(config)# map-class frame-relay MED
Router(config-map-class)# frame-relay interface-queue priority medium
Router(config-map-class)# exit
Router(config)# map-class frame-relay NORM
Router(config-map-class)# frame-relay interface-queue priority normal
Router(config-map-class)# exit
Router(config)# map-class frame-relay LOW
Router(config-map-class)# frame-relay interface-queue priority low
Router(config-map-class)# exit

The following commands enable Frame Relay encapsulation and FR PIPQ on serial interface 0. The sizes of the priority queues are set at a maximum of 20 packets for the high priority queue, 40 for the medium priority queue, 60 for the normal priority queue, and 80 for the low priority queue.

Router(config)# interface Serial0
Router(config-if)# encapsulation frame-relay
Router(config-if)# frame-relay interface-queue priority 20 40 60 80

The following commands assign priority to four PVCs by associating the DLCIs with the configured map classes:

Router(config-if)# frame-relay interface-dlci 100
Router(config-fr-dlci)# class HI
Router(config-fr-dlci)# exit
Router(config-if)# frame-relay interface-dlci 200
Router(config-fr-dlci)# class MED
Router(config-fr-dlci)# exit
Router(config-if)# frame-relay interface-dlci 300
Router(config-fr-dlci)# class NORM
Router(config-fr-dlci)# exit
Router(config-if)# frame-relay interface-dlci 400
Router(config-fr-dlci)# class LOW
Router(config-fr-dlci)# exit

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.

frame-relay interface-queue priority

show frame-relay pvc

show interfaces

show queueing

frame-relay interface-queue priority

To enable the Frame Relay PVC Interface Priority Queueing (FR PIPQ) feature, use the frame-relay interface-queue priority interface configuration command. To disable FR PIPQ, use the no form of this command.

frame-relay interface-queue priority [high-limit medium-limit normal-limit low-limit]

no frame-relay interface-queue priority

To assign priority to a permanent virtual circuit (PVC) within a Frame Relay map class, use the frame-relay interface-queue priority map-class configuration command. To remove priority from a PVC within a Frame Relay map class, use the no form of this command.

frame-relay interface-queue priority {high | medium | normal | low}

no frame-relay interface-queue priority

Syntax Description

high-limit

Size of the high priority queue specified in maximum number of packets.

medium-limit

Size of the medium priority queue specified in maximum number of packets.

normal-limit

Size of the normal priority queue specified in maximum number of packets.

low-limit

Size of the low priority queue specified in maximum number of packets.

high

Assigns high priority to a PVC.

medium

Assigns medium priority to a PVC.

normal

Assigns normal priority to a PVC.

low

Assigns low priority to a PVC.


Defaults

The default sizes of the high, medium, normal, and low priority queues are 20, 40, 60, and 80 packets, respectively.

When FR PIPQ is enabled on the interface, the default PVC priority is normal priority.

Command Modes

Interface configuration

Map-class configuration

Command History

Release
Modification

12.1(2)T

This command was introduced.


Usage Guidelines

FR PIPQ must be enabled on the interface in order for the map-class configuration of PVC priority to be effective.

Before you configure FR PIPQ using the frame-relay interface-queue priority command, the following conditions must be met:

PVCs should be configured to carry a single type of traffic.

The network should be configured with adequate call admission control to prevent starvation of any of the priority queues.

You will not be able to configure FR PIPQ if any queueing other than FIFO queueing is already configured at the interface level. You will be able to configure FR PIPQ when weighted fair queueing (WFQ) is in use, as long as WFQ is the default interface queueing method. Disabling FR PIPQ will restore the interface to dual FIFO queueing if FRF.12 is enabled, FIFO queueing if Frame Relay traffic shaping (FRTS) is enabled, or the default queueing method for the interface.

Examples

In the following example, FR PIPQ is enabled on serial interface 0, and the limits of the high, medium, normal, and low priority queues are set to 10, 20, 30, and 40 packets, respectively. PVC 100 is assigned high priority, so all traffic destined for PVC 100 will be sent to the high priority interface queue.

interface serial0
  encapsulation frame-relay
  frame-relay interface-queue priority 10 20 30 40
  frame-relay interface-dlci 100
   class high_priority_class
 !
 map-class frame-relay high_priority_class
  frame-relay interface-queue priority high

Related Commands

Command
Description

debug priority

Displays priority queueing events.

show frame-relay pvc

Displays statistics about PVCs for Frame Relay interfaces.

show interfaces

Displays statistics for all interfaces configured on the router or access server.

show queue

Displays the contents of packets inside a queue for a particular interface or VC.

show queueing

Lists all or selected configured queueing strategies.


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.

show frame-relay pvc [interface interface][dlci]

Syntax Description

interface

(Optional) Indicates a specific interface for which PVC information will be displayed.

interface

(Optional) Interface number containing the data-link connection identifiers (DLCIs) for which you wish to display PVC information.

dlci

(Optional) A specific DLCI number used on the interface. Statistics for the specified PVC are displayed when a DLCI is also specified.


Defaults

No default behavior or values.

Command Modes

Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.

12.0(1)T

This command was modified to display statistics about virtual access interfaces used for PPP connections over Frame Relay.

12.0(3)XG

This command was modified to include the fragmentation type and size associated with a particular PVC when fragmentation is enabled on the PVC.

12.0(4)T

This command was modified to include the fragmentation type and size associated with a particular PVC when fragmentation is enabled on the PVC.

12.0(5)T

This command was modified to include information on the special voice queue that is created using the queue keyword of the frame-relay voice bandwidth command.

12.1(2)T

This command was modified to include information about the policy map attached to a specific PVC. The command was also modified to include information about the priority configured for a PVC within FR PIPQ.


Usage Guidelines

Use this command to monitor the PPP link control protocol (LCP) state as being open with an "up" state, or closed with a "down" state.

When "vofr" or "vofr cisco" has been configured on the PVC, and a voice bandwidth has been allocated to the class associated with this PVC, configured voice bandwidth and used voice bandwidth are also displayed.

Statistics Reporting

To obtain statistics about PVCs on all Frame Relay interfaces, use this command with no arguments.

To obtain statistics about a PVC that include policy-map configuration or the priority configured for that PVC, use this command with the dlci argument.

Per-VC counters are not incremented at all when either autonomous or silicon switching engine (SSE) switching is configured; therefore, PVC values will be inaccurate if either switching method is used.

Traffic Shaping

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

If a Local Management Interface (LMI) status report indicates that a PVC is not active, then it is marked as inactive. A PVC is marked as deleted if it is not listed in a periodic LMI status message.

Examples

The various displays in this section show sample output for a variety of PVCs. Some of the PVCs carry data only; some carry a combination of voice and data.

Frame Relay PVC Priority Queueing Example

The following is sample output for a PVC that has been assigned high priority:

ed2-36b# show frame-relay pvc 100

PVC Statistics for interface Serial0 (Frame Relay DTE)

DLCI = 100, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0
  input pkts 0             output pkts 0            in bytes 0
  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
  pvc create time 00:00:59, last time pvc status changed 00:00:33
  priority high 

Low Latency Queueing for Frame Relay Example

The following is sample output from the show frame-relay pvc command for a PVC shaped to a 64K committed information rate (CIR) with fragmentation. A policy map is attached to the PVC and is configured with a priority class for voice, two data classes for IP Precedence traffic, and a default class for best-effort traffic. Weighted Random Early Detection (WRED) is used as the drop policy on one of the data classes.

ed2-36b# show frame-relay pvc 100

PVC Statistics for interface Serial1/0 (Frame Relay DTE)

DLCI = 100, DLCI USAGE = LOCAL, PVC STATUS = INACTIVE, INTERFACE = Serial1/0.1

  input pkts 0             output pkts 0            in bytes 0         
  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         
  pvc create time 00:00:42, last time pvc status changed 00:00:42
  service policy mypolicy
 Class voice
  Weighted Fair Queueing
      Strict Priority
      Output Queue: Conversation 72 
        Bandwidth 16 (kbps) Packets Matched 0
        (pkts discards/bytes discards) 0/0
 Class immediate-data
  Weighted Fair Queueing
      Output Queue: Conversation 73 
        Bandwidth 60 (%) Packets Matched 0
        (pkts discards/bytes discards/tail drops) 0/0/0
        mean queue depth: 0
        drops: class  random   tail     min-th   max-th   mark-prob 
               0      0        0        64       128      1/10
               1      0        0        71       128      1/10
               2      0        0        78       128      1/10
               3      0        0        85       128      1/10
               4      0        0        92       128      1/10
               5      0        0        99       128      1/10
               6      0        0        106      128      1/10
               7      0        0        113      128      1/10
               rsvp   0        0        120      128      1/10
 Class priority-data
  Weighted Fair Queueing
      Output Queue: Conversation 74 
        Bandwidth 40 (%) Packets Matched 0 Max Threshold 64 (packets)
        (pkts discards/bytes discards/tail drops) 0/0/0
 Class class-default
  Weighted Fair Queueing
      Flow Based Fair Queueing
      Maximum Number of Hashed Queues 64  Max Threshold 20 (packets)
  Output queue size 0/max total 600/drops 0
  fragment type end-to-end         fragment size 50
  cir 64000     bc   640       be 0         limit 80     interval 10  
  mincir 64000     byte increment 80    BECN response no 
  frags 0         bytes 0         frags delayed 0         bytes delayed 0        
  shaping inactive    
  traffic shaping drops 0

The following is sample output from the show frame-relay pvc command that shows the PVC statistics for serial interface 5 (slot 1 and DLCI 55 are up) during a PPP session over Frame Relay:

 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)

The following is sample output from the show frame-relay pvc command for a PVC carrying Voice over Frame Relay (VoFR) traffic configured via the vofr cisco command. The frame-relay voice bandwidth command has been configured on the class associated with this PVC, as has fragmentation. The fragmentation employed is proprietary to Cisco.

A sample configuration for this scenario is shown first, followed by the output for the show frame-relay pvc command.

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

Note that the "fragment type" field in the show frame-relay pvc command display can have the following entries:

VoFR-cisco—Indicates that fragmented packets will contain the Cisco proprietary header

VoFR—Indicates that fragmented packets will contain the FRF.12 header

end-to-end—Indicates that pure FRF.12 fragmentation is carried on this virtual circuit

The following is sample output from the show frame-relay pvc command for an application employing pure FRF.12 fragmentation. A sample configuration for this scenario is shown first, followed by the output for the show frame-relay pvc command.

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

Note that when voice is not configured, voice bandwidth output is not displayed.

The following is sample output from the show frame-relay pvc command for multipoint subinterfaces carrying data only. The output displays both the subinterface number and the DLCI. This display is the same whether the PVC is configured for static or dynamic addressing. Note that neither fragmentation nor voice is configured on this PVC.

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

The following is sample output from the show frame-relay pvc command for a PVC carrying voice and data traffic, with a special queue specifically for voice traffic created using the frame-relay voice bandwidth command queue keyword:

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

Table 1 provides a listing of the fields in these displays and a description of each field.

Table 1 show frame-relay pvc Field Descriptions 

Field
Description

DLCI

One of the DLCI numbers for the PVC.

DLCI USAGE

Lists SWITCHED when the router or access server is used as a switch, or LOCAL when the router or access server is used as a DTE device.

PVC STATUS

Status of the PVC: ACTIVE, INACTIVE, or DELETED.

INTERFACE

Specific subinterface associated with this DLCI.

input pkts

Number of packets received on this PVC.

output pkts

Number of packets sent on this PVC.

in bytes

Number of bytes received on this PVC.

out bytes

Number of bytes sent on this PVC.

dropped pkts

Number of incoming and outgoing packets dropped by the router at the Frame Relay level.

in FECN pkts

Number of packets received with the FECN bit set.

in BECN pkts

Number of packets received with the BECN bit set.

out FECN pkts

Number of packets sent with the FECN bit set.

out BECN pkts

Number of packets sent with the BECN bit set.

in DE pkts

Number of DE packets received.

out DE pkts

Number of DE packets sent.

out bcast pkts

Number of output broadcast packets.

out bcast bytes

Number of output broadcast bytes.

pvc create time

Time at which the PVC was created.

last time pvc status changed

Time at which the PVC changed status (active to inactive).

priority

Priority assigned to the PVC.

Service type

Type of service performed by this PVC. Can be VoFR or VoFR-cisco.

configured voice bandwidth

Amount of bandwidth in bits per second (bps) reserved for voice traffic on this PVC.

used voice bandwidth

Amount of bandwidth in bps currently being used for voice traffic.

voice reserved queues

Queue numbers reserved for voice traffic on this PVC. This field was removed in Cisco IOS Release 12.0(5)T.

service policy

Name of the output service policy applied to the VC.

Class

Class of traffic being displayed. Output is displayed for each configured class in the policy.

Output Queue

The WFQ conversation to which this class of traffic is allocated.

Bandwidth

Bandwidth in kbps or percentage configured for this class.

Packets Matched

Number of packets that matched this class.

Max Threshold

Maximum queue size for this class when WRED is not used.

pkts discards

Number of packets discarded for this class.

bytes discards

Number of bytes discarded for this class.

tail drops

Number of packets discarded for this class because the queue was full.

mean queue depth

Average queue depth based on the actual queue depth on the interface and the exponential weighting constant. It is a moving average. The minimum and maximum thresholds are compared against this value to determine drop decisions.

drops:

WRED parameters.

class

IP Precedence value.

random

Number of packets randomly dropped when the mean queue depth is between the minimum threshold value and the maximum threshold value for the specified IP Precedence value.

tail

Number of packets dropped when the mean queue depth is greater than the maximum threshold value for the specified IP Precedence value.

min-th

Minimum WRED threshold in number of packets.

max-th

Maximum WRED threshold in number of packets.

mark-prob

Fraction of packets dropped when the average queue depth is at the maximum threshold.

Maximum Number of Hashed Queues

(Applies to class default only) Number of queues available for unclassified flows.

fragment type

Type of fragmentation configured for this PVC. Possible types are:

end-to-end—Fragmented packets contain the standard FRF.12 header

VoFR—Fragmented packets contain the FRF.11 Annex C header

VoFR-cisco—Fragmented packets contain the Cisco proprietary header

fragment size

Size of the fragment payload in bytes.

cir

Current CIR in bps.

bc

Current Committed Burst (Bc) size in bits.

be

Current Excess Burst (Be) size in bits.

limit

Maximum number of bytes sent per internal interval (excess plus sustained).

interval

Interval being used internally (may be smaller than the interval derived from Bc/CIR; this happens when the router determines that traffic flow will be more stable with a smaller configured interval).

mincir

Minimum CIR for the PVC.

byte increment

Number of bytes that will be sustained per internal interval.

BECN response

Indication that Frame Relay has BECN Adaptation configured.

pkts

Number of packets associated with this PVC that have gone through the traffic shaping system.

frags

Total number of fragments shaped on this VC.

bytes

Number of bytes associated with this PVC that have gone through the traffic shaping system.

pkts delayed

Number of packets associated with this PVC that have been delayed by the traffic shaping system.

frags delayed

Number of fragments delayed in the shaping queue before being sent.

bytes delayed

Number of bytes associated with this PVC that have been delayed by the traffic shaping system.

shaping

Indication that shaping will be active for all PVCs that are fragmenting data; otherwise, shaping will be active if the traffic being sent exceeds the CIR for this circuit.

shaping drops

Number of packets dropped by the traffic shaping process.

Voice Queueing Stats

Statistics showing the size of packets, the maximum number of packets, and the number of packets dropped in the special voice queue created using the frame-relay voice bandwidth command queue keyword.

Discard threshold

Maximum number of packets that can be stored in each packet queue. Additional packets received after a queue is full will be discarded.

Dynamic queue count

Number of packet queues reserved for best-effort traffic.

Reserved queue count

Number of packet queues reserved for voice traffic.

Output queue size

Size in bytes of each output queue.

max total

Maximum number of packets of all types that can be queued in all queues.

drops

Number of frames dropped by all output queues.


Related Commands

Command
Description

frame-relay interface-queue priority

Enables FR PIPQ on a Frame Relay interface, and assigns priority to a PVC within a Frame Relay map class.

frame-relay pvc

Configures Frame Relay PVCs for FRF.8 Frame Relay-ATM Service Interworking.

service-policy

Attaches a policy map to an input interface or VC, or an output interface or VC, to be used as the service policy for that interface or VC.

show dial-peer voice

Displays configuration information and call statistics for dial peers.

show frame-relay fragment

Displays Frame Relay fragmentation details.

show frame-relay vofr

Displays details about FRF.11 subchannels being used on VoFR DLCIs.

show interfaces serial

Displays information about a serial interface.

show policy-map interface

Displays the configuration of classes configured for service policies on the specified interface or PVC.

show traffic-shape queue

Displays information about the elements queued at a particular time at the VC (DLCI) level.


show interfaces

To display statistics for all interfaces configured on the router or access server, use the show interfaces privileged EXEC command. The resulting output varies, depending on the network for which an interface has been configured.

show interfaces [type number] [first] [last] [accounting]

Cisco 7200 Series and Cisco 7500 Series with a Packet over SONET Interface Processor

show interfaces [type slot/port] [accounting]

Cisco 7500 Series with Ports on VIPs

show interfaces [type slot/port-adapter/port] [ethernet | serial]

Syntax Description

type

(Optional) Interface type. Allowed values for the type argument are async, bri0, dialer, ethernet, fastethernet, fddi, hssi, loopback, null, serial, tokenring, and tunnel.

For the Cisco 4000 series routers, the type argument can be e1, ethernet, fastethernet, fddi, serial, t1, and token. For the Cisco 4500 series routers, the type argument can also include atm.

For the Cisco 7000 family, the type argument can be atm, e1, ethernet, fastethernet, fddi, serial, t1, and tokenring.

For the Cisco 7500 series, the type argument can also include pos.

number

(Optional) Port number on the selected interface.

first last

(Optional) For Cisco 2500 and 3000 series routers, ISDN BRI only. The first argument can be either 1 or 2. The last argument can only be 2, indicating B channels 1 and 2.

D-channel information is obtained by using the command without the optional arguments.

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.


Command Modes

Privileged EXEC

Command History

Release
Modification

10.0

This command was introduced.

12.0(3)T

This command was modified to include support for flow-based Weighted Random Early Detection (WRED).

12.0(4)T

This command was modified to include enhanced display information for dialer bound interfaces.

12.0(7)T

This command was modified to include the dialer keyword as an interface type, and to reflect the default behavior.

12.1(2)T

This command was modified to display information about the priority queues within the Frame Relay PVC Interface Priority Queueing (FR PIPQ) feature.


Usage Guidelines

The show interfaces command displays statistics for the network interfaces. The resulting display on the Cisco 7200 series routers shows the interface processors in slot order. If you add interface processors after booting the system, they will appear at the end of the list, in the order in which they were inserted.

If you use the show interfaces command on the Cisco 7200 series routers without the slot/port arguments, information for all interface types will be shown. For example, if you enter the show interfaces ethernet command, you will receive information for all Ethernet, serial, Token Ring, and FDDI interfaces. Only by adding the type slot/port argument can you specify a particular interface.

If you enter a show interfaces command for an interface type that has been removed from the router or access server, interface statistics will be displayed accompanied by the following text: "Hardware has been removed."

If you use the show interfaces command on a router or access server for which interfaces are configured to use weighted fair queueing (WFQ) through the fair-queue interface configuration command, additional information is displayed. This information consists of the current and high-water mark number of flows.

If you use the show interfaces command on dialer interfaces configured for binding, the display will report statistics on each physical interface bound to the dialer interface; see the examples in the following section for more information.

You will use the show interfaces command frequently while configuring and monitoring devices. The various forms of the show interfaces commands are shown in detail in the "Examples" section of this command.

Examples

The following is sample output from the show interfaces command. Because your display will depend on the type and number of interface cards in your router or access server, only a portion of the display is shown.

Router# show interfaces

Ethernet 0 is up, line protocol is up
  Hardware is MCI Ethernet, address is 0000.0c00.750c (bia 0000.0c00.750c)
  Internet address is 131.108.28.8, subnet mask is 255.255.255.0
  MTU 1500 bytes, BW 10000 Kbit, DLY 100000 usec, rely 255/255, load 1/255
  Encapsulation ARPA, loopback not set, keepalive set (10 sec)
  ARP type: ARPA, ARP Timeout 4:00:00
  Last input 0:00:00, output 0:00:00, output hang never
  Last clearing of "show interface" counters 0:00:00
  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 2000 bits/sec, 4 packets/sec
     1127576 packets input, 447251251 bytes, 0 no buffer
     Received 354125 broadcasts, 0 runts, 0 giants
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     5332142 packets output, 496316039 bytes, 0 underruns
     0 output errors, 432 collisions, 0 interface resets, 0 restarts
    .
    .
    .

Frame Relay PVC Interface Priority Queueing Example

The following is sample output from the show interfaces command when FR PIPQ is enabled on serial interface 0:

Router# show interfaces Serial0

Serial3/2 is up, line protocol is up
  Hardware is M4T
  MTU 1500 bytes, BW 2048 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation FRAME-RELAY, crc 16, loopback not set
  Keepalive set (10 sec)
  LMI enq sent  7, LMI stat recvd 7, 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
  Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0
  Last input 00:00:08, output 00:00:08, output hang never
  Last clearing of "show interface" counters 00:01:31
  Input queue:0/75/0 (size/max/drops); Total output drops:0
  Queueing strategy:DLCI priority 
  Output queue (queue priority:size/max/drops):
     high:0/20/0, medium:0/40/0, normal:0/60/0, low:0/80/0
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     7 packets input, 173 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
     7 packets output, 98 bytes, 0 underruns
     0 output errors, 0 collisions, 2 interface resets
     0 output buffer failures, 0 output buffers swapped out
     2 carrier transitions     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

Table 2 shows the output fields relevant to FR PIPQ.

Table 2 show interfaces Field Descriptions (When FR PIPQ Is Enabled) 

Field
Description

Queueing strategy

Queueing strategy configured on the interface. Displays "DLCI priority" when FR PIPQ is enabled.