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QoS: Time-Based Thresholds for WRED and Queue Limit

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QoS: Time-Based Thresholds for WRED and Queue Limit

Table Of Contents

QoS: Time-Based Thresholds for WRED and Queue Limit

Contents

Prerequisites for QoS: Time-Based Thresholds for WRED and Queue Limit

Restrictions for QoS: Time-Based Thresholds for WRED and Queue Limit

Information About QoS: Time-Based Thresholds for WRED and Queue Limit

Benefits

Setting Thresholds by Using WRED

Setting Thresholds by Using the queue-limit Command

random-detect Commands with the Milliseconds (ms) Keyword

Mixing Threshold Units of Measure

How to Configure QoS: Time-Based Thresholds for WRED and Queue Limit

Enabling WRED and Using WRED to Specify Thresholds

Using the queue-limit Command to Specify the Thresholds

Attaching the Policy Map to an Interface

Verifying the Configuration

Troubleshooting Tips

Configuration Examples for QoS: Time-Based Thresholds for WRED and Queue Limit

Using WRED to Set Thresholds: Example

Using the queue-limit Command to Set Thresholds: Example

Verifying the Configuration: Example

WRED Threshold Configuration Sample Output

queue-limit command Threshold Configuration Sample Output

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

queue-limit

random-detect atm-clp-based

random-detect clp

random-detect cos

random-detect cos-based

random-detect discard-class

random-detect discard-class-based

random-detect dscp

random-detect dscp-based

random-detect prec-based

random-detect precedence

show policy-map

show policy-map interface


QoS: Time-Based Thresholds for WRED and Queue Limit


First Published: May 07, 2004
Last Updated: February 28, 2006

The QoS: Time-Based Thresholds for WRED and Queue Limit feature allows you to specify the Weighted Random Early Detection (WRED) minimum and maximum thresholds or the queue limit threshold in milliseconds (ms). Previously, these thresholds could only be specified in packets or bytes. Now, all three units of measure are available. Once the threshold limits are configured in a policy map, the policy map can be used on multiple interfaces, including those with different amounts of bandwidth.

History for the QoS: Time-Based Thresholds for WRED and Queue Limit Feature

Release
Modification

12.0(28)S

This feature was introduced.

12.2(28)SB

This feature was integrated into Cisco IOS Release 12.2(28)SB.


Finding Support Information for Platforms and Cisco IOS Software Images

Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Contents

Prerequisites for QoS: Time-Based Thresholds for WRED and Queue Limit

Restrictions for QoS: Time-Based Thresholds for WRED and Queue Limit

Information About QoS: Time-Based Thresholds for WRED and Queue Limit

How to Configure QoS: Time-Based Thresholds for WRED and Queue Limit

Configuration Examples for QoS: Time-Based Thresholds for WRED and Queue Limit

Additional References

Command Reference

Prerequisites for QoS: Time-Based Thresholds for WRED and Queue Limit

Before configuring this feature, a traffic class must be configured and a policy map must exist. To create the traffic class (specifying the appropriate match criteria) and the policy map, use the modular quality of service (QoS) command-line interface (MQC).

Restrictions for QoS: Time-Based Thresholds for WRED and Queue Limit

This feature allows you to specify either the WRED thresholds or the queue limit threshold in packets (the default unit of measure), bytes, or milliseconds (ms). However, these units cannot be mixed. That is, the unit of measure in the same class, in the same policy map, cannot be mixed. For example, if you specify the minimum threshold for a particular class in milliseconds, the maximum threshold for that class must also be in milliseconds.

Information About QoS: Time-Based Thresholds for WRED and Queue Limit

To configure the QoS: Time-Based Thresholds for WRED and Queue Limit feature, you should understand the following concepts:

Benefits

Setting Thresholds by Using WRED

Setting Thresholds by Using the queue-limit Command

random-detect Commands with the Milliseconds (ms) Keyword

Mixing Threshold Units of Measure

Benefits

Queue Limit Thresholds Specified in Additional Units of Measure

Previously, the WRED thresholds and the queue limit thresholds could only be specified in packets or bytes. With this feature, the thresholds can be specified either in packets, bytes or milliseconds. These additional units of measure provide more flexibility and allow you to fine-tune your configuration.

Policy Maps Can be Reused as Needed on Multiple Interfaces

The WRED and queue limit thresholds are specified and configured in policy maps. Once the threshold limits are configured in a policy map, the policy map can be used on multiple interfaces, including those with different amounts of bandwidth. This is especially useful when the bandwidth for a class on given interface is being specified as a percentage of the total bandwidth available.

Setting Thresholds by Using WRED

WRED is a congestion avoidance mechanism. WRED combines the capabilities of the Random Early Detection (RED) algorithm with the IP precedence feature to provide for preferential traffic handling of higher priority packets. WRED can selectively discard lower priority traffic when the interface begins to get congested and provide differentiated performance characteristics for different classes of service.

WRED differs from other congestion avoidance techniques such as queueing strategies because it attempts to anticipate and avoid congestion rather than control congestion once it occurs.

WRED is enabled by using the random-detect command. Then the minimum threshold, maximum threshold, and mark probability denominator can be set to determine the treatment that packets receive by using the appropriate command. For example, the random-detect precedence command can be used to determine the thresholds for a specific IP precedence.

For more information about WRED, refer to the "Congestion Avoidance" section of the Cisco IOS Quality of Service Solutions Configuration Guide.

Setting Thresholds by Using the queue-limit Command

The queue-limit command allows you to specify or modify the maximum number of packets the queue can hold (that is, the threshold) for a class policy configured in a policy map. Packets belonging to a class are subject to the guaranteed bandwidth allocation and the queue limits that characterize the traffic class. With the queue-limit command, the threshold is the aggregate threshold for the entire class.

After a queue has reached its configured queue limit, enqueuing of additional packets to the traffic class causes tail drop or WRED (if configured) to take effect, depending on how the policy map is configured. (Tail drop is a means of avoiding congestion that treats all traffic equally and does not differentiate between classes of service.)

Queues fill during periods of congestion. When the output queue is full and tail drop is in effect, packets are dropped until the congestion is eliminated and the queue is no longer full).

Tail drop is used for distributed class-based weighted fair queueing (DCBWFQ) traffic classes unless you explicitly configure a service policy to use WRED to drop packets as a means of avoiding congestion. Note that if you use WRED instead of tail drop for one or more traffic classes making up a service policy, you must ensure that WRED is not configured for the interface to which you attach that service policy.

For more information about tail drop and DCBWFQ, refer to the "Congestion Management" section of the Cisco IOS Quality of Service Solutions Configuration Guide.

random-detect Commands with the Milliseconds (ms) Keyword

This feature allows you to specify the WRED minimum and maximum thresholds in milliseconds (ms). You can specify the threshold in milliseconds by using the ms keyword available with the random-detect commands listed in Table 1.

Table 1 random-detect Commands with the Milliseconds (ms) Keyword 

Command
Description

random-detect clp

Configures the WRED parameters for a particular cell loss priority (CLP) value, or a particular CLP value for a class policy in a policy map.

random-detect cos

Configures the WRED parameters for a particular class of service (CoS) value, or a particular CoS value for a class policy in a policy map.

random-detect discard-class

Configures the WRED parameters for a particular discard-class, or a particular discard-class for a class policy in a policy map.

random-detect dscp

Configures the WRED parameters for a particular differentiated services code point (DSCP) value, or a particular DSCP value for a class policy in a policy map.

random-detect precedence

Configures WRED parameters for a particular IP precedence, or a particular IP precedence for a class policy in a policy map.


For more information about these commands, see the "Command Reference" section of this document.

Mixing Threshold Units of Measure

With this feature, the thresholds can be specified in packets (the default unit of measure), bytes, or milliseconds (ms). For instance, with WRED, you can specify the minimum threshold and the maximum threshold in packets, bytes, or milliseconds. However, the units cannot be mixed. For example, if you specify the minimum threshold in milliseconds, the maximum threshold must also be specified in milliseconds.

How to Configure QoS: Time-Based Thresholds for WRED and Queue Limit

This section contains the following procedures:

Enabling WRED and Using WRED to Specify Thresholds (required)

Using the queue-limit Command to Specify the Thresholds (required)

Attaching the Policy Map to an Interface (required)

Verifying the Configuration (optional)

Enabling WRED and Using WRED to Specify Thresholds

This procedure allows you to set the WRED thresholds for traffic with a specific value, such as the IP precedence, differentiated services code point (DSCP), Resource Reservation Protocol (RSVP), discard-class, class of service (CoS), or cell loss priority (CLP).

To enable WRED and use it to specify the thresholds for user-defined categories of traffic, perform the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. policy-map policy-name

4. class {class-name | class-default}

5. bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage}

or

6. shape [average | peak] mean-rate [burst-size] [excess-burst-size]

7. random-detect

8. random-detect precedence {precedence | rsvp} min-threshold {bytes | ms | packets} max-threshold {bytes | ms | packets} [mark-probability-denominator]

9. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

policy-map policy-name

Example:

Router(config)# policy-map policy1

Specifies the name of the policy map to be created. Enters policy-map configuration mode.

Enter policy map name.

Step 4 

class {class-name | class-default}

Example:

Router(config-pmap)# class class1

Specifies the class so that you can configure or modify its policy. Enters policy-map class configuration mode.

Enter the class name or specify the default class (class-default).

 

To continue with the configuration, you must either specify a bandwidth (Step 5) or enable traffic shaping (Step 6). Choose one or the other.

Step 5 

bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage}

Example:

Router(config-pmap-c)# bandwidth percent 40

(Optional) Specifies or modifies the bandwidth allocated for a class belonging to a policy map.

Enter the bandwidth to be set or modified.

 

or

Step 6 

shape [average | peak] mean-rate [burst-size] [excess-burst-size]

Example:

Router(config-pmap-c)# shape average 51200

(Optional) Enables either average or peak rate traffic shaping.

Specify either average or peak traffic shaping.

Step 7 

random-detect

Example:

Router(config-pmap-c)# random-detect

Enables WRED or distributed WRED (DWRED).

Step 8 

random-detect precedence {precedence | rsvp} min-threshold {bytes| ms | packets} max-threshold {bytes | ms | packets} [mark-probability-denominator]

Example:

Router(config-pmap-c)# random-detect precedence 2 512 ms 1020 ms

Configures WRED and DWRED parameters for a particular IP precedence.

Specify the IP precedence or RSVP value, and thresholds, as needed.

Note In this example, the WRED parameters were specified for traffic with a specific IP precedence value. Other values can be specified with other random-detect commands. For a list of the other random-detect commands, see Table 1.

Step 9 

exit

Example:

Router(config-pmap-c)# exit

(Optional) Exits policy-map class configuration mode.

Using the queue-limit Command to Specify the Thresholds

The queue-limit command allows you to set the aggregate-level thresholds for an entire class. To specify the thresholds by using the queue-limit command, perform the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. policy-map policy-name

4. class {class-name | class-default}

5. bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage}

or

6. shape [average | peak] mean-rate [burst-size] [excess-burst-size]

7. queue-limit number-of-packets {bytes | ms | packets}

8. exit

DETAILED STEPS

 
Command
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

policy-map policy-name

Example:

Router(config)# policy-map policy1

Specifies the name of the policy map to be created. Enters policy-map configuration mode.

Enter policy map name.

Step 4 

class {class-name | class-default}

Example:

Router(config-pmap)# class class1

Specifies the class so that you can configure or modify its policy. Enters policy-map class configuration mode.

Enter the class name or specify the default class (class-default).

 

To continue with the configuration, you must either specify a bandwidth (Step 5) or enable traffic shaping (Step 6). Choose one or the other.

Step 5 

bandwidth {bandwidth-kbps | remaining percent percentage | percent percentage}

Example:

Router(config-pmap-c)# bandwidth percent 40

(Optional) Specifies or modifies the bandwidth allocated for a class belonging to a policy map.

Enter the bandwidth to be set or modified.

 

or

Step 6 

shape [average | peak] mean-rate [[burst-size] [excess-burst-size]]

Example:

Router(config-pmap-c)# shape average 51200

(Optional) Enables either average or peak rate traffic shaping.

Specifies either average or peak traffic shaping.

Step 7 

queue-limit number-of-packets [bytes | ms | packets]

Example:

Router(config-pmap-c)# queue-limit 200 ms

Specifies or modifies the maximum number of packets the queue can hold (that is, the queue limit) for a class configured in a policy map.

Enter the queue limit. The unit of measure can be bytes, milliseconds, or packets.

Step 8 

exit

Example:

Router(config-pmap-c)# exit

(Optional) Exits policy-map class configuration mode.

Attaching the Policy Map to an Interface

So far, you have specified the threshold in a policy map. The next step is to attach the policy map to an interface. Policy maps can be attached to either the input or output direction of the interface.


Note Depending on the needs of your network, you may need to attach the policy map to a subinterface, an ATM PVC, a Frame Relay DLCI, or other type of interface.


To attach the policy map to an interface, perform the following steps.

SUMMARY STEPS

1. enable

2. configure terminal

3. interface type number

4. pvc [name] vpi/vci [ilmi | qsaal | smds]

5. service-policy {input | output} policy-map-name

6. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

interface type number

Example:

Router(config)# interface serial4/0

Configures an interface (or subinterface) type and enters interface configuration mode.

Enter the interface type number.

Step 4 

pvc [name] vpi/vci [ilmi | qsaal | smds]

Example:

Router(config-if)# pvc cisco 0/16 ilmi

(Optional) Creates or assigns a name to an ATM PVC and specifies the encapsulation type on an ATM PVC. Enters ATM VC configuration mode.

Note This step is required only if you are attaching the policy map to an ATM PVC. If you are not attaching the policy map to an ATM PVC, skip this step and proceed with Step 5.

Step 5 

service-policy {input | output} policy-map-name

Example:

Router(config-if)# service-policy output policy1


Specifies the name of the policy map to be attached to the input or output direction of the interface.

Note Policy maps can be configured on ingress or egress routers. They can also be attached in the input or output direction of an interface. The direction (input or output) and the router (ingress or egress) to which the policy map should be attached varies according your network configuration. When using the service-policy command to attach the policy map to an interface, be sure to choose the router and the interface direction that are appropriate for your network configuration.

Enter the policy map name.

Step 6 

exit

Example:

Router(config-if)# exit

(Optional) Exits interface configuration mode.

Verifying the Configuration

To verify the configuration, perform the following steps.

SUMMARY STEPS

1. enable

2. show policy-map [policy-map]

and/or

show policy-map interface interface-name

3. exit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show policy-map [policy-map]

Example:

Router# show policy-map policy1

Displays all information about a class map, including the match criterion.

Enter class map name.

 

and/or

 

show policy-map interface interface-name

Example:

Router# show policy-map interface serial4/0

Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.

Enter the interface name.

Step 3 

exit

Example:

Router# exit

(Optional) Exits privileged EXEC mode.

Troubleshooting Tips

The commands in the "Verifying the Configuration" section allow you to verify that you achieved the intended configuration and that the feature is functioning correctly. If, after using the show commands listed above, you find that the configuration is not correct or the feature is not functioning as expected, perform these operations:

If the configuration is not the one you intended, complete the following steps:

1. Use the show running-config command and analyze the output of the command.

2. If the policy map does not appear in the output of the show running-config command, enable the logging console command.

3. Attach the policy map to the interface again.

If the packets are not being matched correctly (for example, the packet counters are not incrementing correctly), complete the following procedures:

1. Run the show policy-map command and analyze the output of the command.

2. Run the show running-config command and analyze the output of the command.

3. Use the show policy-map interface command and analyze the output of the command. Check the the following findings:

a. If a policy map applies queueing, and the packets are matching the correct class, but you see unexpected results, compare the number of the packets in the queue with the number of the packets matched.

b. If the interface is congested, and only a small number of the packets are being matched, check the tuning of the transmission (tx) ring, and evaluate whether the queueing is happening on the tx ring. To do this, use the show controllers command, and look at the value of the tx count in the output of the command.

Configuration Examples for QoS: Time-Based Thresholds for WRED and Queue Limit

This section provides the following configuration examples:

Using WRED to Set Thresholds: Example

Using the queue-limit Command to Set Thresholds: Example

Verifying the Configuration: Example

Using WRED to Set Thresholds: Example

In the following example, WRED has been configured in the policy map called "policy1". In this WRED configuration, the bandwidth has been specified as a percentage (80%), and the minimum and maximum thresholds for IP precedence 2 are set to 512 milliseconds and 1020 milliseconds, respectively.

Router> enable
Router# configure terminal
Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth percent 80
Router(config-pmap-c)# random-detect
Router(config-pmap-c)# random-detect precedence 2 512 ms 1020 ms
Router(config-pmap-c)# exit 
Router(config-pmap)# exit 
Router(config)# interface s4/0
Router(config-if)# service-policy output policy1
Router(config-if)# end

Using the queue-limit Command to Set Thresholds: Example

In the following example, a policy map called "policy2" has been configured. The policy2 policy map contains a class called "class1." The bandwidth for this class has been specified as a percentage (80%) and the queue-limit command has been used to set the threshold to 200 milliseconds.

Router> enable
Router# configure terminal
Router(config)# policy-map policy2
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth percent 80
Router(config-pmap-c)# queue-limit 200 ms 
Router(config-pmap-c)# exit 
Router(config-pmap)# exit 
Router(config)# interface s4/0
Router(config-if)# service-policy output policy1
Router(config-if)# end

Verifying the Configuration: Example

To verify that this feature is configured correctly, use either the show policy-map command or the show policy-map interface command.

This section contains two sets of sample output from the show policy-map interface command and the show policy-map command—one set showing the output when WRED is used to configure the feature, one set showing the output when the queue-limit command is used to configure the feature.

WRED Threshold Configuration Sample Output

The following is sample output of the show policy-map command when WRED has been used to specify the thresholds. The words "time-based wred" indicates that the thresholds have been specified in milliseconds (ms).

Router# show policy-map

  Policy Map policy1
    Class class1
      bandwidth 80 (%)
       time-based wred, exponential weight 9

      class    min-threshold    max-threshold    mark-probability
      ----------------------------------------------------------
      0       -                -                1/10
      1       -                -                1/10
      2       512              1024             1/10
      3       -                -                1/10
      4       -                -                1/10
      5       -                -                1/10
      6       -                -                1/10
      7       -                -                1/10

The following is sample output of the show policy-map interface command when WRED has been used to specify the thresholds.

Router# show policy-map interface Ethernet2/0

 Ethernet2/0 

  Service-policy output: policy1 (1100)

    Class-map: class1 (match-all) (1101/1)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: protocol ftp (1102)
      Queueing
      queue limit 16 ms/ 16000 bytes
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts queued/bytes queued) 0/0
      bandwidth 80.00% (%) (8000 kbps)
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 0 ms/ 0 bytes
        class    Transmitted  Random drop   Tail drop    Minimum       Maximum       Mark
                 pkts/bytes   pkts/bytes    pkts/bytes   thresh        thresh        prob
                                                         ms/bytes      ms/bytes
        0        0/0          0/0           0/0           4/4000        8/8000       1/10
        1        0/0          0/0           0/0           4/4500        8/8000       1/10
        2        0/0          0/0           0/0         512/512000   1024/1024000    1/10
        3        0/0          0/0           0/0           5/5500        8/8000       1/10
        4        0/0          0/0           0/0           6/6000        8/8000       1/10
        5        0/0          0/0           0/0           6/6500        8/8000       1/10
        6        0/0          0/0           0/0           7/7000        8/8000       1/10
        7        0/0          0/0           0/0           7/7500        8/8000       1/10

    Class-map: class-default (match-any) (1105/0)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any  (1106)
        0 packets, 0 bytes
        5 minute rate 0 bps
      
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts queued/bytes queued) 0/0

Formula for Converting the Threshold from Milliseconds to Bytes

When converting the threshold from milliseconds to bytes, the following formula is used:

milliseconds * (bandwidth configured for the class) / 8 = total number of bytes

For this example, the following numbers would be used in the formula:

512 ms * 8000 kbps / 8 = 512000 bytes


Note Class1 has a bandwidth of 8000 kbps.


queue-limit command Threshold Configuration Sample Output

The following is sample output of the show policy-map command when the queue-limit command has been used to specify the thresholds in milliseconds.

Router# show policy-map

  Policy Map policy1
    Class class1
      bandwidth 80 (%)
      queue-limit 200 ms

The following is sample output from the show policy-map interface command when the queue-limit command has been used to specify the thresholds.

Router# show policy-map interface

 Ethernet2/0 

  Service-policy output: policy1 (1070)

    Class-map: class1 (match-all) (1071/1)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: protocol ftp (1072)
      Queueing
      queue limit 200 ms/ 200000 bytes
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts queued/bytes queued) 0/0
      bandwidth 80.00% (%) (8000 kbps)

    Class-map: class-default (match-any) (1075/0)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any  (1076)
        0 packets, 0 bytes
        5 minute rate 0 bps
      
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 0/0/0
      (pkts queued/bytes queued) 0/0

Formula for Converting the Threshold from Milliseconds to Bytes

When converting the threshold from milliseconds to bytes, the following formula is used:

milliseconds * (bandwidth configured for the class)/ 8 = total number of bytes

For this example, the following numbers would be used in the formula:

200 ms * 8000 kbps / 8 = 200000 bytes


Note Class1 has a bandwidth of 8000 kbps.


Additional References

The following sections provide references related to the QoS: Time-Based Thresholds for WRED and Queue Limit feature.

Related Documents

Related Topic
Document Title

Quality of service (QoS) commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference, Release 12.3T

Congestion avoidance mechanisms, including tail drop, RED and WRED

Cisco IOS Quality of Service Solutions Configuration Guide

Congestion management mechanisms, including CBWFQ, and DCBWFQ

Cisco IOS Quality of Service Solutions Configuration Guide

Byte-Based WRED

Byte-Based Weight Random Early Detection feature module, Cisco IOS Release 12.0(26)S


Standards

Standards
Title

None


MIBs

MIBs
MIBs Link

None

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


RFCs

RFCs
Title

None


Technical Assistance

Description
Link

The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/techsupport


Command Reference

This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.3 command reference publications.

New Commands

random-detect atm-clp-based

random-detect clp

random-detect cos

random-detect cos-based

random-detect dscp-based

random-detect prec-based

Modified Commands

queue-limit

random-detect discard-class

random-detect discard-class-based

random-detect dscp

random-detect precedence

show policy-map

show policy-map interface

queue-limit

To specify or modify the maximum number of packets the queue can hold for a class policy configured in a policy map, use the queue-limit command in policy-map class configuration mode. To remove the queue packet limit from a class, use the no form of this command.

queue-limit number-of-packets

no queue-limit number-of-packets

Syntax Description

number-of-packets

A number in the range from 1 to 64 specifying the maximum number of packets that the queue for this class can accumulate.


Defaults

On the Versatile Interface Processor (VIP)-based platforms, the default value is chosen as a function of the bandwidth assigned to the traffic class. The default value is also based on available buffer memory. If sufficient buffer memory is available, the default queue-limit value is equal to the number of 250-byte packets that would lead to a latency of 500 milliseconds (ms) when the packets are delivered at the configured rate. For example, if two 250-byte packets are required to lead to a latency of 500 ms, the default number-of-packets value would be 2.

On all other platforms, the default is 64.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.0(5)T

This command was introduced.

12.0(5)XE

This command was integrated into Cisco IOS Release 12.0(5)XE. Support for VIP-enabled Cisco 7500 series routers was added.

12.1(5)T

This command was implemented on the VIP-enabled Cisco 7500 series routers.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

Weighted fair queueing (WFQ) creates a queue for every class for which a class map is defined. Packets satisfying the match criteria for a class accumulate in the queue reserved for the class until they are sent, which occurs when the queue is serviced by the fair queueing process. When the maximum packet threshold you defined for the class is reached, enqueueing of any further packets to the class queue causes tail drop or, if Weighted Random Early Detection (WRED) is configured for the class policy, packet drop to take effect.

Overriding Queue Limits Set by the Bandwidth Command

The bandwidth command can be used with the Modular Command-Line Interface (MQC) to specify the bandwidth for a particular class. When used with the MQC, the bandwidth command uses a default queue limit for the class. This queue limit can be modified using the queue-limit command, thereby overriding the default set by the bandwidth command.


Note Using the queue-limit command to modify the default queue-limit is especially important for higher-speed interfaces, in order to meet the minimum bandwidth guarantees required by the interface.


Examples

The following example configures a policy map called policy11 to contain policy for a class called acl203. Policy for this class is set so that the queue reserved for it has a maximum packet limit of 40.

policy-map policy11
 class acl203
  bandwidth 2000
  queue-limit 40

Related Commands

Command
Description

class (policy-map)

Specifies the name of the class whose policy you want to create or change, and the default class (commonly known as the class-default class) before you configure its policy.

class class-default

Specifies the default traffic class whose bandwidth is to be configured or modified.

policy-map

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.


random-detect atm-clp-based

To enable weighted random early detection (WRED) on the basis of the ATM cell loss priority (CLP) of a packet, use the random-detect atm-clp-based command in policy-map class configuration mode. To disable WRED, use the no form of this command.

random-detect atm-clp-based clp-value

no random-detect atm-clp-based clp-value

Syntax Description

clp-value

CLP value. Valid values are 0 or 1.


Defaults

When WRED is configured, the default minimum and maximum thresholds are determined on the basis of output buffering capacity and the transmission speed for the interface.

The default maximum probability denominator is 10.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.0(28)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Examples

In the following example, WRED is configured on the basis of the ATM CLP. In this configuration, the random-detect atm-clp-based command has been configured and an ATM CLP of 1 has been specified.

Router> enable
Router# configure terminal
Router(config)# policy-map policymap1
Router(config-pmap)# class class1
Router(config-pmap-c)# random-detect atm-clp-based 1
Router(config-pmap-c)# end

Related Commands

Command
Description

random-detect clp

Specifies the ATM CLP value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling WRED.

random-detect cos

Specifies the CoS value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling WRED.

random-detect cos-based

Enables WRED on the basis of the CoS value of a packet.

show policy-map

Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

show policy-map interface

Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.


random-detect clp

To specify the ATM cell loss priority (CLP) value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling weighted random early detection (WRED), use the random-detect clp command in policy-map class configuration mode. To reset the thresholds and maximum probability denominator to the default values for the specified ATM CLP, use the no form of this command.

random-detect clp clp-value min-threshold max-threshold max-probability-denominator

no random-detect clp clp-value min-threshold max-threshold max-probability-denominator

Syntax Description

clp-value

CLP value. Valid values are 0 or 1.

min-threshold

Minimum threshold in number of packets. Valid values are 1 to 4096.

max-threshold

Maximum threshold in number of packets. Valid values are 1 to 4096.

max-probability-denominator

Denominator for the fraction of packets dropped when the average queue depth is at the maximum threshold. Valid values are 1 to 65535.


Defaults

The default values for the min-threshold and max-threshold arguments are based on the output buffering capacity and the transmission speed for the interface.

The default for the max-probability-denominator argument is 10; 1 out of every 10 packets is dropped at the maximum threshold.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.0(28)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

Note the following points when using the random-detect clp command:

When the average queue length reaches the minimum threshold, WRED randomly drops some packets with the specified IP precedence.

When the average queue length exceeds the maximum threshold, WRED drops all packets with the specified IP precedence.

The max-probability-denominator argument is the fraction of packets dropped when the average queue depth is at the maximum threshold. For example, if the denominator is 512, 1 out of every 512 packets is dropped when the average queue is at the maximum threshold.

Examples

In the following example, WRED has been enabled using the random-detect clp command. With the random-detect clp command, the ATM CLP has been specified, along with the minimum and maximum thresholds, and the maximum probability denominator.

Router> enable

Router# configure terminal

Router(config)# policy-map policymap1

Router(config-pmap)# class class1

Router(config-pmap-c)# random-detect clp 1 12 25 1/10

Router(config-pmap-c)# end

Related Commands

Command
Description

random-detect atm-clp-based

Enables WRED on the basis of the ATM CLP of a packet.

random-detect cos

Specifies the CoS value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling WRED.

random-detect cos-based

Enables WRED on the basis of the CoS value of a packet.

show policy-map

Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

show policy-map interface

Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.


random-detect cos

To specify the class of service (CoS) value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling weighted random early detection (WRED), use the random-detect cos command in policy-map class configuration mode. To reset the thresholds and maximum probability denominator to the default values for the specified CoS, use the no form of this command.

random-detect cos cos-value min-threshold max-threshold max-probability-denominator

no random-detect cos cos-value min-threshold max-threshold max-probability-denominator

Syntax Description

cos-value

Specific IEEE 802.1Q CoS value from 0 to 7.

min-threshold

Minimum threshold in number of packets. Valid values are 1 to 4096.

max-threshold

Maximum threshold in number of packets. Valid values are 1 to 4096.

max-probability-denominator

Denominator for the fraction of packets dropped when the average queue depth is at the maximum threshold. Valid values are 1 to 65535.


Defaults

The default values for the min-threshold and max-threshold arguments are based on the output buffering capacity and the transmission speed for the interface.

The default value for the max-probability-denominator argument is 10; 1 out of every 10 packets is dropped at the maximum threshold.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.0(28)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

Note the following points when using the random-detect cos command:

When the average queue length reaches the minimum threshold, WRED randomly drops some packets with the specified IP precedence.

When the average queue length exceeds the maximum threshold, WRED drops all packets with the specified IP precedence.

The max-probability-denominator argument is the fraction of packets dropped when the average queue depth is at the maximum threshold. For example, if the denominator is 512, 1 out of every 512 packets is dropped when the average queue is at the maximum threshold.

Examples

In the following example, WRED has been enabled using the random-detect cos command. With the random-detect cos command, the CoS value has been specified, along with the minimum and maximum thresholds, and the maximum probability denominator.

Router> enable

Router# configure terminal

Router(config)# policy-map policymap1

Router(config-pmap)# class class1

Router(config-pmap-c)# random-detect cos 1 12 25 1/10

Router(config-pmap-c)# end

Related Commands

Command
Description

random-detect atm-clp-based

Configures WRED on the basis of the ATM CLP of a packet.

random-detect clp

Specifies the ATM CLP value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling WRED.

random-detect cos-based

Enables WRED on the basis of the CoS value of a packet.

show policy-map

Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

show policy-map interface

Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.


random-detect cos-based

To enable weighted random early detection (WRED) on the basis of the class of service (CoS) value of a packet, use the random-detect cos-based command in policy-map class configuration mode. To disable WRED, use the no form of this command.

random-detect cos-based cos-value

no random-detect cos-based cos-value

Syntax Description

cos-value

Specific IEEE 802.1Q CoS value from 0 to 7.


Defaults

When WRED is configured, the default minimum and maximum thresholds are determined on the basis of output buffering capacity and the transmission speed for the interface.

The default maximum probability denominator is 10.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.0(28)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Examples

In the following example, WRED is configured on the basis of the CoS value. In this configuration, the random-detect cos-based command has been configured and a CoS value of 2 has been specified.

Router> enable
Router# configure terminal
Router(config)# policy-map policymap1
Router(config-pmap)# class class1
Router(config-pmap-c)# random-detect cos-based 2
Router(config-pmap-c)# end

Related Commands

Command
Description

random-detect atm-clp-based

Enables WRED on the basis of the ATM CLP of a packet.

random-detect clp

Specifies the ATM CLP value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling WRED.

random-detect cos

Specifies the CoS value of a packet, the minimum and maximum thresholds, and the maximum probability denominator used for enabling WRED.

show policy-map

Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

show policy-map interface

Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.


random-detect discard-class

To configure the weighted random early detection (WRED) parameters for a discard-class value for a class policy in a policy map, use the random-detect discard-class command in policy-map class configuration mode. To disable this feature, use the no form of this command.

random-detect discard-class value min-threshold max-threshold max-probability-denominator

no random-detect discard-class value min-threshold max-threshold max-probability-denominator

Syntax Description

value

Discard class. Valid values are 0 to 7.

min-threshold

Minimum threshold in number of packets. Valid values are 1 to 4096. When the average queue length reaches the minimum threshold, WRED randomly drops some packets with the specified IP precedence.

max-threshold

Maximum threshold in number of packets. Valid values are 1 to 4096. When the average queue length exceeds the maximum threshold, WRED drops all packets with the specified IP precedence.

max-probability-denominator

Denominator for the fraction of packets dropped when the average queue depth is at the maximum threshold. For example, if the denominator is 512, 1 out of every 512 packets is dropped when the average queue is at the maximum threshold. Valid values are 1 to 65535. The default is 10; 1 out of every 10 packets is dropped at the maximum threshold.


Defaults

To return the values to the default for the discard class, use the no form of this command.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.2(13)T

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

When you configure the random-detect discard-class command on an interface, packets are given preferential treatment based on the discard class of the packet. Use the random-detect discard-class command to adjust the discard class for different discard class values.

Examples

The following example shows that if the discard class is 2, there is a 10 percent chance that packets will be dropped if there are more packets than the minimum threshold of 100 packets or there are fewer packets than the maximum threshold of 200 packets:

policy-map set-MPLS-PHB
  class IP-AF11
    bandwidth percent 40
    random-detect discard-class-based
    random-detect-discard-class 2 100 200 10

Related Commands

Command
Description

bandwidth (policy-map class)

Specifies or modifies the bandwidth allocated for a class belonging to a policy map.

fair-queue (class-default)

Specifies the number of dynamic queues to be reserved for use by the class-default class as part of the default class policy.

random-detect discard-class-based

Bases WRED on the discard class value of a packet.

show policy-map interface

Displays the configuration of all classes configured for all service policies on the specified interface or displays the classes for the service policy for a specific PVC on the interface.


random-detect discard-class-based

To base weighted random early detection (WRED) on the discard class value of a packet, use the random-detect discard-class-based command in policy-map class configuration mode. To disable this feature, use the no form of this command.

random-detect discard-class-based

no random-detect discard-class-based

Syntax Description

This command has no arguments or keywords.

Defaults

The defaults are router-dependent.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.2(13)T

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

Enter this command so that WRED is based on the discard class instead of on the IP precedence field.

Examples

The following example shows that random detect is based on the discard class value of a packet:

policy-map name 
  class-name 
    bandwidth percent 40
    random-detect discard-class-based

Related Commands

Command
Description

match discard-class

Matches packets of a certain discard class.


random-detect dscp

To change the minimum and maximum packet thresholds for the differentiated services code point (DSCP) value, use the random-detect dscp command in interface configuration mode. To return the minimum and maximum packet thresholds to the default for the DSCP value, use the no form of this command.

random-detect dscp dscp-alue min-threshold max-threshold [max-probability-denominator]

no random-detect dscp dscp-value min-threshold max-threshold [max-probability-denominator]

Syntax Description

dscp-value

Specifies the DSCP value. The DSCP value can be a number from 0 to 63, or it can be one of the following keywords: ef, af11, af12, af13, af21, af22, af23, af31, af32, af33, af41, af42, af43, cs1, cs2, cs3, cs4, cs5, or cs7.

min-threshold

Minimum threshold in number of packets. The value range of this argument is from 1 to 4096. When the average queue length reaches the minimum threshold, Weighted Random Early Detection (WRED) randomly drops some packets with the specified DSCP value.

max-threshold

Maximum threshold in number of packets. The value range of this argument is from the value of the min-threshold argument to 4096. When the average queue length exceeds the maximum threshold, WRED drops all packets with the specified DSCP value.

max-probability-denominator

(Optional) Denominator for the fraction of packets dropped when the average queue depth is at the maximum threshold. For example, if the denominator is 512, 1 out of every 512 packets is dropped when the average queue is at the maximum threshold. The value range is from 1 to 65536. The default is 10; 1 out of every 10 packets is dropped at the maximum threshold.


Defaults

If WRED is using the DSCP value to calculate the drop probability of a packet, all entries of the DSCP table are initialized with the default settings shown in Table 2 in the "Usage Guidelines" section of this command.

Command Modes

Interface configuration

Command History

Release
Modification

12.1(5)T

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

The random-detect dscp command allows you to specify the DSCP value. The DSCP value can be a number from 0 to 63, or it can be one of the following keywords: ef, af11, af12, af13, af21, af22, af23, af31, af32, af33, af41, af42, af43, cs1, cs2, cs3, cs4, cs5, or cs7.

This command must be used in conjunction with the random-detect (interface) command.

Additionally, the random-detect dscp command is available only if you specified the dscp-based argument when using the random-detect (interface) command.

Table 2 lists the default settings used by the random-detect dscp command for the DSCP value specified. Table 2 lists the DSCP value, and its corresponding minimum threshold, maximum threshold, and max probability. The last row of the table (the row labeled "default") shows the default settings used for any DSCP value not specifically shown in the table.

Table 2 random-detect dscp Default Settings 

DSCP
(Precedence)
Minimum Threshold
Maximum Threshold
Max Probability

af11

32

40

1/10

af12

28

40

1/10

af13

24

40

1/10

af21

32

40

1/10

af22

28

40

1/10

af23

24

40

1/10

af31

32

40

1/10

af32

28

40

1/10

af33

24

40

1/10

af41

32

40

1/10

af42

28

40

1/10

af43

24

40

1/10

cs1

22

40

1/10

cs2

24

40

1/10

cs3

26

40

1/10

cs4

28

40

1/10

cs5

30

40

1/10

cs6

32

40

1/10

cs7

34

40

1/10

ef

36

40

1/10

rsvp

36

40

1/10

default

20

40

1/10


Examples

The following example enables WRED to use the DSCP value af22. The minimum threshold for DSCP value af22 is 28, the maximum threshold is 40, and the max probability is 10.

random-detect dscp af22 20 40 10

Related Commands

Command
Description

random-detect (interface)

Enables WRED or DWRED.

show queueing

Lists all or selected configured queueing strategies.

show queueing interface

Displays the queueing statistics of an interface or VC.


random-detect dscp-based

To base weighted random early detection (WRED) on the differentiated services code point (DSCP) value of a packet, use the random-detect dscp-based command in policy-map class configuration mode. To disable this feature, use the no form of this command.

random-detect dscp-based

no random-detect dscp-based

Syntax Description

This command has no arguments or keywords.

Defaults

The defaults are platform-dependent.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.0(28)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

With the random-detect dscp-based command, WRED is based on the DSCP value of the packet.

Use the random-detect dscp-based command before configuring the random-detect dscp command.

Examples

The following example shows that random detect is based on the DSCP value of a packet:

Router> enable
Router# configure terminal
Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth percent 80
Router(config-pmap-c)# random-detect dscp-based
Router(config-pmap-c)# random-detect dscp af22 512 ms 1020 ms
Router(config-pmap-c)# exit 

Related Commands

Command
Description

random-detect

Enables WRED or DWRED.

random-detect dscp

Configures the WRED parameters for a particular DSCP value; configures the WRED parameters for a particular DSCP value for a class policy in a policy map.


random-detect prec-based

To base weighted random early detection (WRED) on the precedence value of a packet, use the random-detect prec-based command in policy-map class configuration mode. To disable this feature, use the no form of this command.

random-detect prec-based

no random-detect prec-based

Syntax Description

This command has no arguments or keywords.

Defaults

The defaults are platform-dependent.

Command Modes

Policy-map class configuration

Command History

Release
Modification

12.0(28)S

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

With the random-detect prec-based command, WRED is based on the IP precedence value of the packet.

Use the random-detect prec-based command before configuring the random-detect precedence command.

Examples

The following example shows that random detect is based on the precedence value of a packet:

Router> enable
Router# configure terminal
Router(config)# policy-map policy1
Router(config-pmap)# class class1
Router(config-pmap-c)# bandwidth percent 80
Router(config-pmap-c)# random-detect prec-based
Router(config-pmap-c)# random-detect precedence 2 500 ms 1000 ms
Router(config-pmap-c)# exit 

Related Commands

Command
Description

random-detect

Enables WRED or DWRED.

random-detect precedence

Configures the WRED and DWRED parameters for a particular IP precedence; configures WRED parameters for a particular IP precedence for a class policy in a policy map.


random-detect precedence

To configure Weighted Random Early Detection (WRED) and distributed WRED (DWRED) parameters for a particular IP Precedence, use the random-detect precedence command in interface configuration mode. To configure WRED parameters for a particular IP Precedence for a class policy in a policy map, use the random-detect precedence command in policy-map class configuration mode. To return the values to the default for the precedence, use the no form of this command.

random-detect precedence {precedence | rsvp} min-threshold max-threshold max-probability-denominator

no random-detect precedence {precedence | rsvp} min-threshold max-threshold max-probability-denominator

Syntax Description

precedence

IP Precedence number. The value range is from 0 to 7. For Cisco 7000 series routers with an RSP7000 interface processor and Cisco 7500 series routers with a VIP2-40 interface processor (VIP2-50 interface processor strongly recommended), the precedence value range is from 0 to 7 only; see Table 3 in the "Usage Guidelines" section of this command.

rsvp

Indicates Resource Reservation Protocol (RSVP) traffic.

min-threshold

Minimum threshold in number of packets. The value range of this argument is from 1 to 4096. When the average queue length reaches the minimum threshold, WRED randomly drops some packets with the specified IP Precedence.

max-threshold

Maximum threshold in number of packets. The value range of this argument is from the value of the min-threshold argument to 4096. When the average queue length exceeds the maximum threshold, WRED drops all packets with the specified IP Precedence.

max-probability-denominator

Denominator for the fraction of packets dropped when the average queue depth is at the maximum threshold. For example, if the denominator is 512, 1 out of every 512 packets is dropped when the average queue is at the maximum threshold. The value range is from 1 to 65536. The default is 10; 1 out of every 10 packets is dropped at the maximum threshold.


Defaults

For all precedences, the max-probability-denominator default is 10, and the max-threshold is based on the output buffering capacity and the transmission speed for the interface.

The default min-threshold depends on the precedence. The min-threshold for IP Precedence 0 corresponds to half of the max-threshold. The values for the remaining precedences fall between half the max-threshold and the max-threshold at evenly spaced intervals. See Table 3 in the "Usage Guidelines" section of this command for a list of the default minimum threshold values for each IP Precedence.

Command Modes

Interface configuration when used on an interface

Policy-map class configuration when used to specify class policy in a policy map

Command History

Release
Modification

11.1 CC

This command was introduced.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

WRED is a congestion avoidance mechanism that slows traffic by randomly dropping packets when congestion exists. DWRED is similar to WRED but uses the Versatile Interface Processor (VIP) instead of the Route Switch Processor (RSP).

When you configure the random-detect command on an interface, packets are given preferential treatment based on the IP Precedence of the packet. Use the random-detect precedence command to adjust the treatment for different precedences.

If you want WRED or DWRED to ignore the precedence when determining which packets to drop, enter this command with the same parameters for each precedence. Remember to use reasonable values for the minimum and maximum thresholds.

Note that if you use the random-detect precedence command to adjust the treatment for different precedences within class policy, you must ensure that WRED is not configured for the interface to which you attach that service policy.

Table 3 lists the default minimum threshold value for each IP Precedence.

Table 3 Default WRED and DWRED Minimum Threshold Values 

 
Minimum Threshold Value
(Fraction of Maximum Threshold Value)
IP Precedence
WRED
DWRED

0

9/18

8/16

1

10/18

9/16

2

11/18

10/16

3

12/18

11/16

4

13/18

12/16

5

14/18

13/16

6

15/18

14/16

7

16/18

15/16

RSVP

17/18



Note The default WRED or DWRED parameter values are based on the best available data. We recommend that you do not change the parameters from their default values unless you have determined that your applications would benefit from the changed values.


The DWRED feature is supported only on Cisco 7000 series routers with an RSP7000 card and Cisco 7500 series routers with a VIP2-40 or greater interface processor. A VIP2-50 interface processor is strongly recommended when the aggregate line rate of the port adapters on the VIP is greater than DS3. A VIP2-50 interface processor is required for OC-3 rates.

To use DWRED, distributed Cisco Express Forwarding (dCEF) switching must first be enabled on the interface. For more information on dCEF, refer to the Cisco IOS Switching Services Configuration Guide and the Cisco IOS Switching Services Command Reference.


Note The DWRED feature is not supported in a class policy.


Examples

The following example enables WRED on the interface and specifies parameters for the different IP Precedences:

interface Hssi0/0/0
 description 45Mbps to R1
 ip address 10.200.14.250 255.255.255.252
 random-detect
 random-detect precedence 0 32 256 100
 random-detect precedence 1 64 256 100
 random-detect precedence 2 96 256 100
 random-detect precedence 3 120 256 100
 random-detect precedence 4 140 256 100
 random-detect precedence 5 170 256 100
 random-detect precedence 6 290 256 100
 random-detect precedence 7 210 256 100
 random-detect precedence rsvp 230 256 100

The following example configures policy for a class called acl10 included in a policy map called policy10. Class acl101 has these characteristics: a minimum of 2000 kbps of bandwidth are expected to be delivered to this class in the event of congestion and a weight factor of 10 is used to calculate the average queue size. For congestion avoidance, WRED packet drop is used, not tail drop. IP Precedence is reset for levels 0 through 4.

policy-map policy10
class acl10
 bandwidth 2000
 random-detect
 random-detect exponential-weighting-constant 10
 random-detect precedence 0 32 256 100
 random-detect precedence 1 64 256 100
 random-detect precedence 2 96 256 100
 random-detect precedence 3 120 256 100
 random-detect precedence 4 140 256 100

Related Commands

Command
Description

bandwidth (policy-map class)

Specifies or modifies the bandwidth allocated for a class belonging to a policy map.

fair-queue (class-default)

Specifies the number of dynamic queues to be reserved for use by the class-default class as part of the default class policy.

random-detect dscp

Changes the minimum and maximum packet thresholds for the DSCP value.

random-detect (per VC)

Enables per-VC WRED or per-VC DWRED.

random-detect exponential-weighting-constant

Configures the WRED and DWRED exponential weight factor for the average queue size calculation.

random-detect flow count

Sets the flow count for flow-based WRED.

show policy-map interface

Displays the configuration of all classes configured for all service policies on the specified interface or displays the classes for the service policy for a specific PVC on the interface.

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 policy-map

To display the configuration of all classes for a specified service policy map or all classes for all existing policy maps, use the show policy-map command in EXEC mode.

show policy-map [policy-map]

Syntax Description

policy-map

(Optional) Name of the service policy map whose complete configuration is to be displayed.


Command Default

All existing policy map configurations are displayed.

Command Modes

EXEC

Command History

Release
Modification

12.0(5)T

This command was introduced.

12.0(5)XE

This command was integrated into Cisco IOS Release 12.0(5)XE.

12.0(7)S

This command was integrated into Cisco IOS Release 12.0(7)S.

12.1(1)E

This command was integrated into Cisco IOS Release 12.1(1)E.

12.2(13)T

The output of this command was modified for the Percentage-Based Policing and Shaping feature and includes the bandwidth percentage used when calculating traffic policing and shaping.

12.0(28)S

The output of this command was modified for the QoS: Percentage-Based Policing feature to display the committed (conform) burst (bc) and excess (peak) burst (be) sizes in milliseconds (ms).

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB.


Usage Guidelines

The show policy-map command displays the configuration of a service policy map created using the policy-map command. You can use the show policy-map command to display all class configurations comprising any existing service policy map, whether or not that service policy map has been attached to an interface.

Examples

The following is sample output from the show policy-map command. This sample output displays the contents of a policy map called "policy1." In policy 1, traffic policing on the basis of a committed information rate (CIR) of 20 percent has been configured, and the bc and be have been specified in milliseconds. As part of the traffic policing configuration, optional conform, exceed, and violate actions have been specified.

Router# show policy-map policy1

  Policy Map policy1
    Class class1
     police cir percent 20 bc 300 ms pir percent 40 be 400 ms
       conform-action transmit 
       exceed-action drop 
       violate-action drop 

Table 4 describes the significant fields shown in the display.

Table 4 show policy-map Field Descriptions 

Field
Description

Policy Map

Name of policy map displayed.

Class

Name of class configured in policy map displayed.

police

Indicates that traffic policing on the basis of specified percentage of bandwidth has been enabled. The committed burst (bc) and excess burst (be) sizes have been specified in milliseconds (ms), and optional conform, exceed, and violate actions have been specified.


Related Commands

Command
Description

policy-map

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

show policy-map class

Displays the configuration for the specified class of the specified policy map.

show policy-map interface

Displays the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific PVC on the interface.


show policy-map interface

To display the packet statistics of all classes that are configured for all service policies either on the specified interface or subinterface or on a specific permanent virtual circuit (PVC) on the interface, use the show policy-map interface command in privileged EXEC mode.

show policy-map interface [type access-control] interface-name [vc [vpi/] vci] [dlci dlci]
[
input | output]

ATM Shared Port Adapter

show policy-map interface atm slot/subslot/port[.subinterface]

Syntax Description

type access-control

(Optional) Displays class maps configured to determine the exact pattern to look for in the protocol stack of interest.

interface-name

Name of the interface or subinterface whose policy configuration is to be displayed.

vc

(Optional) For ATM interfaces only, shows the policy configuration for a specified PVC. The name can be up to 16 characters long.

vpi/

(Optional) ATM network virtual path identifier (VPI) for this PVC. On the Cisco 7200 and 7500 series routers, this value ranges from 0 to 255.

The vpi and vci arguments cannot both be set to 0; if one is 0, the other cannot be 0.

vci

(Optional) ATM network virtual channel identifier (VCI) for this PVC. This value ranges from 0 to 1 less than the maximum value set for this interface by the atm vc-per-vp command. Typically, the lower values 0 to 31 are reserved for specific traffic (F4 Operation, Administration, and Maintenance (OAM), switched virtual circuit (SVC) signaling, Integrated Local Management Interface (ILMI), and so on) and should not be used.

The VCI is a 16-bit field in the header of the ATM cell. The VCI value is unique only on a single link, not throughout the ATM network, because it has local significance only.

The vpi and vci arguments cannot both be set to 0; if one is 0, the other cannot be 0.

dlci

(Optional) Indicates that a specific PVC for which policy configuration will be displayed.

dlci

(Optional) A specific data-link connection identifier (DLCI) number used on the interface. Policy configuration for the corresponding PVC will be displayed when a DLCI is specified.

input

(Optional) Indicates that the statistics for the attached input policy will be displayed.

output

(Optional) Indicates that the statistics for the attached output policy will be displayed.

slot

(ATM Shared Port Adapter only) Chassis slot number. Refer to the appropriate hardware manual for slot information. For SIPs, refer to the platform-specific SPA hardware installation guide or the corresponding "Identifying Slots and Subslots for SIPs and SPAs" topic in the platform-specific SPA software configuration guide.

/subslot

(ATM Shared Port Adapter only) Secondary slot number on a SPA interface processor (SIP) where a SPA is installed. Refer to the platform-specific SPA hardware installation guide and the corresponding "Specifying the Interface Address on a SPA" topic in the platform-specific SPA software configuration guide for subslot information.

/port

(ATM Shared Port Adapter only) Port or interface number. Refer to the appropriate hardware manual for port information. For SPAs, refer to the corresponding "Specifying the Interface Address" topics in the platform-specific SPA software configuration guide.

.subinterface

(ATM Shared Port Adapter onlyOptional) Subinterface number. The number that precedes the period must match the number to which this subinterface belongs. The range is 1 to 4,294,967,293.


Defaults

The absence of both the forward slash (/) and a vpi value defaults the vpi value to 0. If this value is omitted, information for all virtual circuits (VCs) on the specified ATM interface or subinterface is displayed.

ATM Shared Port Adapter

When used with the ATM shared port adapter, this command has no default behavior or values.

Command Modes

Privileged EXEC

ATM Shared Port Adapter

When used with the ATM shared port adapter, EXEC or privileged EXEC.

Command History

Release
Modification

12.0(5)T

This command was introduced.

12.0(5)XE

This command was integrated into Cisco IOS Release 12.0(5)XE.

12.0(7)S

This command was integrated into Cisco IOS Release 12.0(7)S.

12.1(1)E

This command was integrated into Cisco IOS Release 12.1(1)E.

12.1(2)T

This command was modified to display information about the policy for all Frame Relay PVCs on the interface, or, if a DLCI is specified, the policy for that specific PVC. This command was also modified to display the total number of packets marked by the quality of service (QoS) set action.

12.1(3)T

This command was modified to display per-class accounting statistics.

12.2(4)T

This command was modified for two-rate traffic policing. It now can display burst parameters and associated actions.

12.2(8)T

The command was modified for the Policer Enhancement — Multiple Actions feature and the WRED — Explicit Congestion Notification (ECN) feature.

For the Policer Enhancement — Multiple Actions feature, the command was modified to display the multiple actions configured for packets conforming to, exceeding, or violating a specific rate.

For the WRED — Explicit Congestion Notification (ECN) feature, the command displays ECN marking information

12.2(13)T

The following modifications were made:

This command was modified for the Percentage-Based Policing and Shaping feature.

This command was modified for the Class-Based RTP and TCP Header Compression feature.

This command was modified as part of the Modular QoS CLI (MQC) Unconditional Packet Discard feature. Traffic classes in policy maps can now be configured to discard packets belonging to a specified class.

This command was modified to display the Frame Relay DLCI number as a criterion for matching traffic inside a class map.

This command was modified to display Layer 3 packet length as a criterion for matching traffic inside a class map.

This command was modified for the Enhanced Packet Marking feature. A mapping table (table map) can now be used to convert and propagate packet-marking values.

12.2(15)T

This command was modified to display Frame Relay voice-adaptive traffic-shaping information.

12.0(28)S

This command was modified for the QoS: Percentage-Based Policing feature to include milliseconds when calculating the committed (conform) burst (bc) and excess (peak) burst (be) sizes.

12.3(14)T

This command was modified to display bandwidth estimation parameters.

12.2(18)SXE

This command was integrated into Cisco IOS Release 12.2(18)SXE. This command was modified to display aggregate WRED statistics for the ATM shared port adapter. Note that changes were made to the syntax, defaults, and command modes. These changes are labelled "ATM Shared Port Adapter."

12.4(4)T

The type access-control keywords were added to support flexible packet matching.

12.2(28)SB

This command was integrated into Cisco IOS Release 12.2(28)SB and its output was modified to display either legacy (nondistributed processing) QoS or hierarchical queueing framework (HQF) parameters on FR interfaces or PVCs.


Usage Guidelines

The show policy-map interface command displays the packet statistics for classes on the specified interface or the specified PVC only if a service policy has been attached to the interface or the PVC.

You can use the interface-name argument to display output for a PVC only for enhanced ATM port adapters (PA-A3) that support per-VC queueing.

The counters displayed after the show policy-map interface command is entered are updated only if congestion is present on the interface.

The show policy-map interface command displays policy information about Frame Relay PVCs only if Frame Relay Traffic Shaping (FRTS) is enabled on the interface.

The show policy-map interface command displays ECN marking information only if ECN is enabled on the interface.

To determine if shaping is active with HQF, check the queue depth field of the "(queue depth/total drops/no-buffer drops)" line in the show policy-map interface command output.

Examples

This section provides sample output from typical show policy-map interface commands. Depending upon the interface in use and the options enabled, the output you see may vary slightly from the ones shown below.

Example of Weighted Fair Queueing (WFQ) on Serial Interface

The following sample output of the show policy-map interface command displays the statistics for the serial 3/1 interface, to which a service policy called mypolicy (configured as shown below) is attached. Weighted fair queueing (WFQ) has been enabled on this interface. See Table 5 for an explanation of the significant fields that commonly appear in the command output.

policy-map mypolicy
  class voice
    priority 128
  class gold
   bandwidth 100
  class silver
   bandwidth 80
   random-detect

Router# show policy-map interface serial3/1 output

 Serial3/1 

  Service-policy output: mypolicy

    Class-map: voice (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip precedence 5 
      Weighted Fair Queueing
        Strict Priority
        Output Queue: Conversation 264 
        Bandwidth 128 (kbps) Burst 3200 (Bytes)
        (pkts matched/bytes matched) 0/0
        (total drops/bytes drops) 0/0

    Class-map: gold (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip precedence 2 
      Weighted Fair Queueing
        Output Queue: Conversation 265 
        Bandwidth 100 (kbps) Max Threshold 64 (packets)
        (pkts matched/bytes matched) 0/0
        (depth/total drops/no-buffer drops) 0/0/0

    Class-map: silver (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip precedence 1 
      Weighted Fair Queueing
        Output Queue: Conversation 266 
        Bandwidth 80 (kbps)
        (pkts matched/bytes matched) 0/0
        (depth/total drops/no-buffer drops) 0/0/0
         exponential weight: 9
         mean queue depth: 0

class     Transmitted       Random drop      Tail drop    Minimum Maximum  Mark
          pkts/bytes        pkts/bytes       pkts/bytes    thresh  thresh  prob
0             0/0               0/0              0/0           20      40  1/10
1             0/0               0/0              0/0           22      40  1/10
2             0/0               0/0              0/0           24      40  1/10
3             0/0               0/0              0/0           26      40  1/10
4             0/0               0/0              0/0           28      40  1/10
5             0/0               0/0              0/0           30      40  1/10
6             0/0               0/0              0/0           32      40  1/10
7             0/0               0/0              0/0           34      40  1/10
rsvp          0/0               0/0              0/0           36      40  1/10

Class-map: class-default (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any 

Example of Traffic Shaping on Serial Interface

The following sample output from the show policy-map interface command displays the statistics for the serial 3/2 interface, to which a service policy called p1 (configured as shown below) is attached. Traffic shaping has been enabled on this interface. See Table 5 for an explanation of the significant fields that commonly appear in the command output.

policy-map p1
  class c1
   shape average 320000

Router# show policy-map interface serial3/2 output

 Serial3/2 

  Service-policy output: p1

    Class-map: c1 (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip precedence 0 
      Traffic Shaping
        Target    Byte   Sustain   Excess    Interval  Increment Adapt
        Rate      Limit  bits/int  bits/int  (ms)      (bytes)   Active
        320000    2000   8000      8000      25        1000      -

        Queue     Packets   Bytes     Packets   Bytes     Shaping
        Depth                         Delayed   Delayed   Active
        0         0         0         0         0         no

    Class-map: class-default (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any 

Table 5 describes significant fields commonly shown in the displays. The fields in the table are grouped according to the relevant QoS feature.

Table 5 show policy-map interface Field Descriptions 1  

Field
Description
Fields Associated with Classes or Service Policies

Service-policy output

Name of the output service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets and bytes

Number of packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of packets coming in to the class.

Note If the packets are compressed over an outgoing interface, the improved packet rate achieved by packet compression is not reflected in the offered rate. Also, if the packets are classified before they enter a combination of tunnels (for example, a generic routing encapsulation (GRE) tunnel and an IP Security (IPSec) tunnel), the offered rate does not include all the extra overhead associated with tunnel encapsulation in general. Depending on the configuration, the offered rate may include no overhead, may include the overhead for only one tunnel encapsulation, or may include the overhead for all tunnel encapsulations. In most of the GRE and IPSec tunnel configurations, the offered rate includes the overhead for GRE tunnel encapsulation only.

drop rate

Rate, in kbps, at which packets are dropped from the class. The drop rate is calculated by subtracting the number of successfully transmitted packets from the offered rate.

Note In distributed architecture platforms (such as the C7500), the value of the transfer rate, calculated as the difference between the offered rate and the drop rate counters, can sporadically deviate from the average by up to 20 percent or more. This can occur while no corresponding burst is registered by independent traffic analyser equipment.

Match

Match criteria specified for the class of traffic. Choices include criteria such as IP precedence, IP differentiated services code point (DSCP) value, Multiprotocol Label Switching (MPLS) experimental (EXP) value, access groups, and QoS groups. For more information about the variety of match criteria options available, refer to the chapter "Configuring the Modular Quality of Service Command-Line Interface" in the Cisco IOS Quality of Service Solutions Configuration Guide.

Fields Associated with Queueing (If Enabled)

Output Queue

The weighted fair queueing (WFQ) conversation to which this class of traffic is allocated.

Bandwidth

Bandwidth, in either kbps or percentage, configured for this class and the burst size.

pkts matched/bytes matched

Number of packets (also shown in bytes) matching this class that were placed in the queue. This number reflects the total number of matching packets queued at any time. Packets matching this class are queued only when congestion exists. If packets match the class but are never queued because the network was not congested, those packets are not included in this total. However, if process switching is in use, the number of packets is always incremented even if the network is not congested.

depth/total drops/no-buffer drops

Number of packets discarded for this class. No-buffer indicates that no memory buffer exists to service the packet.

Fields Associated with Weighted Random Early Detection (WRED) (If Enabled)

exponential weight

Exponent used in the average queue size calculation for a WRED parameter group.

mean queue depth

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

class

IP precedence level.

Transmitted pkts/bytes

Number of packets (also shown in bytes) passed through WRED and not dropped by WRED.

Note If there is insufficient memory in the buffer to accommodate the packet, the packet can be dropped after the packet passes through WRED. Packets dropped because of insufficient memory in the buffer (sometimes referred to as "no-buffer drops") are not taken into account by the WRED packet counter.

Random drop pkts/bytes

Number of packets (also shown in bytes) randomly dropped when the mean queue depth is between the minimum threshold value and the maximum threshold value for the specified IP precedence level.

Tail drop pkts/bytes

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

Minimum thresh

Minimum threshold. Minimum WRED threshold in number of packets.

Maximum thresh

Maximum threshold. Maximum WRED threshold in number of packets.

Mark prob

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

Fields Associated with Traffic Shaping (If Enabled)

Target Rate

Rate used for shaping traffic.

Byte Limit

Maximum number of bytes that can be transmitted per interval. Calculated as follows:

((Bc+Be) /8) x 1

Sustain bits/int

Committed burst (Bc) rate.

Excess bits/int

Excess burst (Be) rate.

Interval (ms)

Time interval value in milliseconds (ms).

Increment (bytes)

Number of credits (in bytes) received in the token bucket of the traffic shaper during each time interval.

Queue Depth

Current queue depth of the traffic shaper.

Packets

Total number of packets that have entered the traffic shaper system.

Bytes

Total number of bytes that have entered the traffic shaper system.

Packets Delayed

Total number of packets delayed in the queue of the traffic shaper before being transmitted.

Bytes Delayed

Total number of bytes delayed in the queue of the traffic shaper before being transmitted.

Shaping Active

Indicates whether the traffic shaper is active. For example, if a traffic shaper is active, and the traffic being sent exceeds the traffic shaping rate, a "yes" appears in this field.

1 A number in parentheses may appear next to the service-policy output name, class-map name, and match criteria information. The number is for Cisco internal use only and can be disregarded.


Example of Precedence-Based Aggregate WRED on ATM Shared Port Adapter

The following sample output of the show policy-map interface command displays the statistics for the ATM shared port adapter interface 4/1/0.10, to which a service policy called prec-aggr-wred (configured as shown below) is attached. Because aggregate WRED has been enabled on this interface, the class through Mark Prob statistics are aggregated by subclasses. See Table 6 for an explanation of the significant fields that commonly appear in the command output.

Router(config)# policy-map prec-aggr-wred
Router(config-pmap)# class class-default
Router(config-pmap-c)# random-detect aggregate
Router(config-pmap-c)# random-detect precedence values 0 1 2 3 minimum thresh 10 
maximum-thresh 100 mark-prob 10
Router(config-pmap-c)# random-detect precedence values 4 5 minimum-thresh 40 
maximum-thresh 400 mark-prob 10
Router(config-pmap-c)# random-detect precedence values 6 minimum-thresh 60 maximum-thresh 
600 mark-prob 10
Router(config-pmap-c)# random-detect precedence values 7 minimum-thresh 70 maximum-thresh 
700 mark-prob 10
Router(config-pmap-c)# interface ATM4/1/0.10 point-to-point
Router(config-subif)# ip address 10.0.0.2 255.255.255.0
Router(config-subif)# pvc 10/110

Router(config-subif)# service-policy output prec-aggr-wred



Router# show policy-map interface a4/1/0.10

 ATM4/1/0.10: VC 10/110 -

  Service-policy output: prec-aggr-wred

    Class-map: class-default (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any 
        Exp-weight-constant: 9 (1/512)
        Mean queue depth: 0
        class       Transmitted     Random drop      Tail drop     Minimum   Maximum  Mark
	pkts/bytes	pkts/bytes	pkts/bytes	thresh	thresh	prob
        
        0  1  2  3       0/0               0/0              0/0           10     100  1/10
        4  5             0/0               0/0              0/0           40     400  1/10
        6                0/0               0/0              0/0           60     600  1/10
        7                0/0               0/0              0/0           70     700  1/10

Example of DSCP-Based Aggregate WRED on ATM Shared Port Adapter

The following sample output of the show policy-map interface command displays the statistics for the ATM shared port adapter interface 4/1/0.11, to which a service policy called dscp-aggr-wred (configured as shown below) is attached. Because aggregate WRED has been enabled on this interface, the class through Mark Prob statistics are aggregated by subclasses. See Table 6 for an explanation of the significant fields that commonly appear in the command output.

Router(config)# policy-map dscp-aggr-wred
Router(config-pmap)# class class-default
Router(config-pmap-c)# random-detect dscp-based aggregate minimum-thresh 1 maximum-thresh 
10 mark-prob 10
Router(config-pmap-c)# random-detect dscp values 0 1 2 3 4 5 6 7 minimum-thresh 10 
maximum-thresh 20 mark-prob 10
Router(config-pmap-c)# random-detect dscp values 8 9 10 11 minimum-thresh 10 
maximum-thresh 40 mark-prob 10
Router(config)# interface ATM4/1/0.11 point-to-point
Router(config-subif)# ip address 10.0.0.2 255.255.255.0
Router(config-subif)# pvc 11/101

Router(config-subif)# service-policy output dscp-aggr-wred

Router# show policy-map interface a4/1/0.11

 ATM4/1/0.11: VC 11/101 -

  Service-policy output: dscp-aggr-wred

    Class-map: class-default (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any 
        Exp-weight-constant: 0 (1/1)
        Mean queue depth: 0
        class       Transmitted     Random drop      Tail drop     Minimum   Maximum  Mark
                  	pkts/bytes	pkts/bytes	pkts/bytes	thresh	thresh	prob
        default          0/0               0/0              0/0            1      10  1/10
        0  1  2  3 
        4  5  6  7       0/0               0/0              0/0           10      20  1/10
        8  9  10 11      0/0               0/0              0/0           10      40  1/10

Table 6 describes the significant fields shown in the display when aggregate WRED is configured for an ATM shared port adapter.

Table 6 show policy-map interface Field Descriptions—Configured for Aggregate WRED on ATM Shared Port Adapter

Field
Description

exponential weight

Exponent used in the average queue size calculation for a Weighted Random Early Detection (WRED) parameter group.

mean queue depth

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

Note When Aggregate Weighted Random Early Detection (WRED) is enabled, the following WRED statistics will be aggregated based on their subclass (either their IP precedence or differentiated services code point (DSCP) value).

class

IP precedence level or differentiated services code point (DSCP) value.

Transmitted pkts/bytes

Number of packets (also shown in bytes) passed through WRED and not dropped by WRED.

Note If there is insufficient memory in the buffer to accommodate the packet, the packet can be dropped after the packet passes through WRED. Packets dropped because of insufficient memory in the buffer (sometimes referred to as "no-buffer drops") are not taken into account by the WRED packet counter.

Random drop pkts/bytes

Number of packets (also shown in bytes) randomly dropped when the mean queue depth is between the minimum threshold value and the maximum threshold value for the specified IP precedence level or DSCP value.

Tail drop pkts/bytes

Number of packets dropped when the mean queue depth is greater than the maximum threshold value for the specified IP precedence level or DSCP value.

Minimum thresh

Minimum threshold. Minimum WRED threshold in number of packets.

Maximum thresh

Maximum threshold. Maximum WRED threshold in number of packets.

Mark prob

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


Frame Relay Voice-Adaptive Traffic-Shaping show policy interface Command Example

The following sample output shows that Frame Relay voice-adaptive traffic shaping is currently active and has 29 seconds left on the deactivation timer. With traffic shaping active and the deactivation time set, this means that the current sending rate on DLCI 201 is minCIR, but if no voice packets are detected for 29 seconds, the sending rate will increase to CIR.

Router# show policy interface Serial3/1.1

 Serial3/1.1:DLCI 201 -

  Service-policy output:MQC-SHAPE-LLQ1
    
    Class-map:class-default (match-any)
      1434 packets, 148751 bytes
      30 second offered rate 14000 bps, drop rate 0 bps
      Match:any
      Traffic Shaping
           Target/Average   Byte   Sustain   Excess    Interval  Increment
             Rate           Limit  bits/int  bits/int  (ms)      (bytes)
            63000/63000     1890   7560      7560      120       945
    
        Adapt  Queue     Packets   Bytes     Packets   Bytes     Shaping
        Active Depth                         Delayed   Delayed   Active
        BECN   0         1434      162991    26        2704      yes
        Voice Adaptive Shaping active, time left 29 secs 

Table 7 describes the significant fields shown in the display. Significant fields that are not described in Table 7 are described in Table 5, "show policy-map interface Field Descriptions."

Table 7 show policy-map interface Field Descriptions—Configured for Frame Relay Voice-Adaptive Traffic Shaping

Field
Description

Voice Adaptive Shaping active/inactive

Indicates whether Frame Relay voice-adaptive traffic shaping is active or inactive.

time left

Number of seconds left on the Frame Relay voice-adaptive traffic shaping deactivation timer.


Two-Rate Traffic Policing show policy-map interface Command Example

The following is sample output from the show policy-map interface command when two-rate traffic policing has been configured. In the example below, 1.25 Mbps of traffic is sent ("offered") to a policer class.

Router# show policy-map interface serial3/0 

 Serial3/0

  Service-policy output: policy1

   Class-map: police (match all)
    148803 packets, 36605538 bytes
    30 second offered rate 1249000 bps, drop rate 249000 bps
    Match: access-group 101
    police:
     cir 500000 bps, conform-burst 10000, pir 1000000, peak-burst 100000
     conformed 59538 packets, 14646348 bytes; action: transmit
     exceeded 59538 packets, 14646348 bytes; action: set-prec-transmit 2
     violated 29731 packets, 7313826 bytes; action: drop
     conformed 499000 bps, exceed 500000 bps violate 249000 bps
   Class-map: class-default (match-any)
    19 packets, 1990 bytes
    30 seconds offered rate 0 bps, drop rate 0 bps
    Match: any

The two-rate traffic policer marks 500 kbps of traffic as conforming, 500 kbps of traffic as exceeding, and 250 kbps of traffic as violating the specified rate. Packets marked as conforming will be sent as is, and packets marked as exceeding will be marked with IP Precedence 2 and then sent. Packets marked as violating the specified rate are dropped.

Table 8 describes the significant fields shown in the display.

Table 8 show policy-map interface Field Descriptions—Configured for Two-Rate Traffic Policing 

Field
Description

police

Indicates that the police command has been configured to enable traffic policing. Also, displays the specified CIR, conform burst size, peak information rate (PIR), and peak burst size used for marking packets.

conformed

Displays the action to be taken on packets conforming to a specified rate. Displays the number of packets and bytes on which the action was taken.

exceeded

Displays the action to be taken on packets exceeding a specified rate. Displays the number of packets and bytes on which the action was taken.

violated

Displays the action to be taken on packets violating a specified rate. Displays the number of packets and bytes on which the action was taken.


Multiple Traffic Policing Actions show policy-map interface Command Example

The following is sample output from the show policy-map command when the Policer Enhancement — Multiple Actions feature has been configured. The sample output from the show policy-map interface command displays the statistics for the serial 3/2 interface, to which a service policy called "police" (configured as shown below) is attached.

policy-map police
  class class-default
   police cir 1000000 pir 2000000
     conform-action transmit 
     exceed-action set-prec-transmit 4
     exceed-action set-frde-transmit 
     violate-action set-prec-transmit 2
     violate-action set-frde-transmit 

Router# show policy-map interface serial3/2

Serial3/2: DLCI 100 -

Service-policy output: police

    Class-map: class-default (match-any)
      172984 packets, 42553700 bytes
      5 minute offered rate 960000 bps, drop rate 277000 bps
      Match: any 
     police:
         cir 1000000 bps, bc 31250 bytes, pir 2000000 bps, be 31250 bytes
       conformed 59679 packets, 14680670 bytes; actions:
         transmit 
exceeded 59549 packets, 14649054 bytes; actions:
         set-prec-transmit 4
         set-frde-transmit 
       violated 53758 packets, 13224468 bytes; actions: 
         set-prec-transmit 2
         set-frde-transmit 
       conformed 340000 bps, exceed 341000 bps, violate 314000 bps

The sample output from show policy-map interface command shows the following:

59679 packets were marked as conforming packets (that is, packets conforming to the CIR) and were transmitted unaltered.

59549 packets were marked as exceeding packets (that is, packets exceeding the CIR but not exceeding the PIR). Therefore, the IP Precedence value of these packets was changed to an IP Precedence level of 4, the discard eligibility (DE) bit was set to 1, and the packets were transmitted with these changes.

53758 packets were marked as violating packets (that is, exceeding the PIR). Therefore, the IP Precedence value of these packets was changed to an IP Precedence level of 2, the DE bit was set to 1, and the packets were transmitted with these changes.


Note Actions are specified by using the action argument of the police command. For more information about the available actions, see the police command reference page.


Table 9 describes the significant fields shown in the display.

Table 9 show policy-map interface Field Descriptions—Configured for Multiple Traffic Policing Actions

Field
Description

police

Indicates that the police command has been configured to enable traffic policing. Also, displays the specified CIR, conform burst size (BC), PIR, and peak burst size (BE) used for marking packets.

conformed, packets, bytes, actions

Displays the number of packets (also shown in bytes) marked as conforming to a specified rate and the actions taken on the packet. If there are multiple actions, each action is listed separately.

exceeded, packets, bytes, actions

Displays the number of packets (also shown in bytes) marked as exceeding a specified rate and the actions taken on the packet. If there are multiple actions, each action is listed separately.

violated, packets, bytes, actions

Displays the number of packets (also shown in bytes) marked as violating a specified rate and the actions taken on the packet. If there are multiple actions, each action is listed separately.


Explicit Congestion Notification show policy-map interface Command Example

The following is sample output from the show policy-map interface command when the WRED — Explicit Congestion Notification (ECN) feature has been configured. The words "explicit congestion notification" included in the output indicate that ECN has been enabled.

Router# show policy-map interface Serial4/1

 Serial4/1

  Service-policy output:policy_ecn
        Class-map:prec1 (match-all)
          1000 packets, 125000 bytes
          30 second offered rate 14000 bps, drop rate 5000 bps
          Match:ip precedence 1
          Weighted Fair Queueing
            Output Queue:Conversation 42
            Bandwidth 20 (%)
            Bandwidth 100 (kbps)
            (pkts matched/bytes matched) 989/123625
        (depth/total drops/no-buffer drops) 0/455/0
             exponential weight:9
             explicit congestion notification
             mean queue depth:0

     class   Transmitted  Random drop  Tail drop   Minimum     Maximum     Mark
             pkts/bytes   pkts/bytes    pkts/bytes threshold   threshold   probability
       0       0/0          0/0          0/0          20          40        1/10
       1     545/68125      0/0          0/0          22          40        1/10
       2       0/0          0/0          0/0          24          40        1/10
       3       0/0          0/0          0/0          26          40        1/10
       4       0/0          0/0          0/0          28          40        1/10
       5       0/0          0/0          0/0          30          40        1/10
       6       0/0          0/0          0/0          32          40        1/10
       7       0/0          0/0          0/0          34          40        1/10
     rsvp      0/0          0/0          0/0          36          40        1/10
     class   ECN Mark 
            pkts/bytes
       0     0/0
       1    43/5375
       2     0/0
       3     0/0
       4     0/0
       5     0/0
       6     0/0
       7     0/0
     rsvp    0/0

Table 10 describes the significant fields shown in the display.

Table 10 show policy-map interface Field Descriptions—Configured for ECN 

Field
Description

explicit congestion notification

Indication that Explicit Congestion Notification is enabled.

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.

class

IP precedence value.

Transmitted pkts/bytes

Number of packets (also shown in bytes) passed through WRED and not dropped by WRED.

Note If there is insufficient memory in the buffer to accommodate the packet, the packet can be dropped after the packet passes through WRED. Packets dropped because of insufficient memory in the buffer (sometimes referred to as "no-buffer drops") are not taken into account by the WRED packet counter.

Random drop pkts/bytes

Number of packets (also shown in bytes) 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 drop pkts/bytes

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

Minimum threshold

Minimum WRED threshold in number of packets.

Maximum threshold

Maximum WRED threshold in number of packets.

Mark probability

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

ECN Mark pkts/bytes

Number of packets (also shown in bytes) marked by ECN.


Class-Based RTP and TCP Header Compression show policy-map interface Command Example

The following sample output from the show policy-map interface command shows the RTP header compression has been configured for a class called "prec2" in the policy map called "p1".

The show policy-map interface command output displays the type of header compression configured (RTP), the interface to which the policy map called "p1" is attached (Serial 4/1), the total number of packets, the number of packets compressed, the number of packets saved, the number of packets sent, and the rate at which the packets were compressed (in bits per second (bps)).

In this example, User Datagram Protocol (UDP)/RTP header compressions have been configured, and the compression statistics are included at the end of the display.

Router# show policy-map interface Serial4/1

Serial4/1

Service-policy output:p1

    Class-map:class-default (match-any)
      1005 packets, 64320 bytes
      30 second offered rate 16000 bps, drop rate 0 bps
      Match:any
compress:
          header ip rtp
          UDP/RTP Compression:
          Sent:1000 total, 999 compressed,
                41957 bytes saved, 17983 bytes sent
                3.33 efficiency improvement factor
                99% hit ratio, five minute miss rate 0 misses/sec, 0 max
                 rate 5000 bps

Table 11 describes the significant fields shown in the display.

Table 11 show policy-map interface Field Descriptions—Configured for Class-Based RTP and TCP Header Compression1  

Field
Description

Service-policy output

Name of the output service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets, bytes

Number of packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of packets coming in to the class.

Note If the packets are compressed over an outgoing interface, the improved packet rate achieved by packet compression is not reflected in the offered rate. Also, if the packets are classified before they enter a combination of tunnels (for example, a generic routing encapsulation (GRE) tunnel and an IP Security (IPSec) tunnel), the offered rate does not include all the extra overhead associated with tunnel encapsulation in general. Depending on the configuration, the offered rate may include no overhead, may include the overhead for only one tunnel encapsulation, or may include the overhead for all tunnel encapsulations. In most of the GRE and IPSec tunnel configurations, the offered rate includes the overhead for GRE tunnel encapsulation only.

UDP/RTP Compression

Indicates that RTP header compression has been configured for the class.

Sent total

Count of every packet sent, both compressed packets and full-header packets.

Sent compressed

Count of number of compressed packets sent.

bytes saved

Total number of bytes saved (that is, bytes not needing to be sent).

bytes sent

Total number of bytes sent for both compressed and full-header packets.

efficiency improvement factor

The percentage of increased bandwidth efficiency as a result of header compression. For example, with RTP streams, the efficiency improvement factor can be as much as 2.9 (or 290 percent).

hit ratio

Used mainly for troubleshooting purposes, this is the percentage of packets found in the context database. In most instances, this percentage should be high.

five minute miss rate

The number of new traffic flows found in the last five minutes.

misses/sec
max

The average number of new traffic flows found per second, and the highest rate of new traffic flows to date.

rate

The actual traffic rate (in bits per second) after the packets are compressed.

1 A number in parentheses may appear next to the service-policy output name and the class-map name. The number is for Cisco internal use only and can be disregarded.


Modular QoS CLI (MQC) Unconditional Packet Discard show policy-map interface Command Example

The following sample output from the show policy-map interface command displays the statistics for the Serial2/0 interface, to which a policy map called "policy1" is attached. The discarding action has been specified for all the packets belonging to a class called "c1." In this example, 32000 bps of traffic is sent ("offered") to the class and all of them are dropped. Therefore, the drop rate shows 32000 bps.


Router# show policy-map interface Serial2/0

 Serial2/0 

  Service-policy output: policy1

    Class-map: c1 (match-all)
       10184 packets, 1056436 bytes
       5 minute offered rate 32000 bps, drop rate 32000 bps
       Match: ip precedence 0
       drop

Table 12 describes the significant fields shown in the display.

Table 12 show policy-map interface Field Descriptions—Configured for MQC Unconditional Packet Discard1  

Field
Description

Service-policy output

Name of the output service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets, bytes

Number of packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of packets coming in to the class.

Note If the packets are compressed over an outgoing interface, the improved packet rate achieved by packet compression is not reflected in the offered rate. Also, if the packets are classified before they enter a combination of tunnels (for example, a generic routing encapsulation (GRE) tunnel and an IP Security (IPSec) tunnel), the offered rate does not include all the extra overhead associated with tunnel encapsulation in general. Depending on the configuration, the offered rate may include no overhead, may include the overhead for only one tunnel encapsulation, or may include the overhead for all tunnel encapsulations. In most of the GRE and IPSec tunnel configurations, the offered rate includes the overhead for GRE tunnel encapsulation only.

drop rate

Rate, in kbps, at which packets are dropped from the class. The drop rate is calculated by subtracting the number of successfully transmitted packets from the offered rate.

Note In distributed architecture platforms (such as the C7500), the value of the tranfer rate, calculated as the difference between the offered rate and the drop rate counters, can sporadically diviate from the average by up to 20 percent or more. This can occur while no corresponding burst is registered by independent traffic analyser equipment

Match

Match criteria specified for the class of traffic. Choices include criteria such as the Layer 3 packet length, IP precedence, IP DSCP value, MPLS experimental value, access groups, and QoS groups. For more information about the variety of match criteria options available, refer to the chapter "Configuring the Modular Quality of Service Command-Line Interface" in the Cisco IOS Quality of Service Solutions Configuration Guide.

drop

Indicates that the packet discarding action for all the packets belonging to the specified class has been configured.

1 A number in parentheses may appear next to the service-policy output name and the class-map name. The number is for Cisco internal use only and can be disregarded.


Percentage-Based Policing and Shaping show policy-map interface Command Example

The following sample output from the show policy-map interface command shows traffic policing configured using a CIR based on a bandwidth of 20 percent. The CIR and committed burst (Bc) in milliseconds (ms) are included in the display.

Router# show policy-map interface Serial3/1

 Serial3/1 

  Service-policy output: mypolicy

    Class-map: gold (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any
      police:
          cir 20 % bc 10 ms
          cir 2000000 bps, bc 2500 bytes
          pir 40 % be 20 ms
          pir 4000000 bps, be 10000 bytes
     conformed 0 packets, 0 bytes; actions: 
      transmit 
     exceeded 0 packets, 0 bytes; actions: 
       drop
      violated 0 packets, 0 bytes; actions:
       drop
      conformed 0 bps, exceed 0 bps, violate 0 bps

Table 13 describes the significant fields shown in the display.

Table 13 show policy-map interface Field Descriptions—Configured for Percentage-Based Policing and Shaping1

Field
Description

Service-policy output

Name of the output service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets, bytes

Number of packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of packets coming in to the class.

Note If the packets are compressed over an outgoing interface, the improved packet rate achieved by packet compression is not reflected in the offered rate. Also, if the packets are classified before they enter a combination of tunnels (for example, a generic routing encapsulation (GRE) tunnel and an IP Security (IPSec) tunnel), the offered rate does not include all the extra overhead associated with tunnel encapsulation in general. Depending on the configuration, the offered rate may include no overhead, may include the overhead for only one tunnel encapsulation, or may include the overhead for all tunnel encapsulations. In most of the GRE and IPSec tunnel configurations, the offered rate includes the overhead for GRE tunnel encapsulation only.

police

Indicates that traffic policing based on a percentage of bandwidth has been enabled. Also, displays the bandwidth percentage, the CIR, and the committed burst (Bc) size in ms.

conformed, actions

Displays the number of packets and bytes marked as conforming to the specified rates, and the action to be taken on those packets.

exceeded, actions

Displays the number of packets and bytes marked as exceeding the specified rates, and the action to be taken on those packets.

1 A number in parentheses may appear next to the service-policy output name and the class-map name. The number is for Cisco internal use only and can be disregarded.


Traffic Shaping show policy-map interface Command Example

The following sample output from the show policy-map interface command (shown below) displays the statistics for the serial 3/2 interface. Traffic shaping has been enabled on this interface, and an average rate of 20 percent of the bandwidth has been specified.

Router# show policy-map interface Serial3/2

Serial3/2 

  Service-policy output: p1

    Class-map: c1 (match-all)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any
      Traffic Shaping
        Target/Average      Byte   Sustain    Excess      Interval  Increment  Adapt
        Rate              Limit  bits/int  bits/int    (ms)     (bytes)   Active 
         20 %                       10 (ms)    20 (ms)
        201500/201500       1952   7808       7808        38         976       -

        Queue     Packets   Bytes     Packets   Bytes     Shaping
        Depth                         Delayed   Delayed   Active
        0         0         0         0         0         no

Table 14 describes the significant fields shown in the display.

Table 14 show policy-map interface Field Descriptions—Configured for Percentage-Based Policing and Shaping (with Traffic Shaping Enabled)1  

Field
Description

Service-policy output

Name of the output service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets, bytes

Number of packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of packets coming in to the class.

Note If the packets are compressed over an outgoing interface, the improved packet rate achieved by packet compression is not reflected in the offered rate. Also, if the packets are classified before they enter a combination of tunnels (for example, a generic routing encapsulation (GRE) tunnel and an IP Security (IPSec) tunnel), the offered rate does not include all the extra overhead associated with tunnel encapsulation in general. Depending on the configuration, the offered rate may include no overhead, may include the overhead for only one tunnel encapsulation, or may include the overhead for all tunnel encapsulations. In most of the GRE and IPSec tunnel configurations, the offered rate includes the overhead for GRE tunnel encapsulation only.

drop rate

Rate, in kbps, at which packets are dropped from the class. The drop rate is calculated by subtracting the number of successfully transmitted packets from the offered rate.

Match

Match criteria specified for the class of traffic. Choices include criteria such as the Layer 3 packet length, IP precedence, IP DSCP value, MPLS experimental value, access groups, and quality of service (QoS) groups. For more information about the variety of match criteria options that are available, refer to the chapter "Configuring the Modular Quality of Service Command-Line Interface" in the Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.2.

Traffic Shaping

Indicates that traffic shaping based on a percentage of bandwidth has been enabled.

Target /Average Rate

Rate (percentage) used for shaping traffic and the number of packets meeting that rate.

Byte Limit

Maximum number of bytes that can be transmitted per interval. Calculated as follows:

((Bc+Be) /8 ) x 1

Sustain bits/int

Committed burst (Bc) rate.

Excess bits/int

Excess burst (Be) rate.

Interval (ms)

Time interval value in milliseconds (ms).

Increment (bytes)

Number of credits (in bytes) received in the token bucket of the traffic shaper during each time interval.

Adapt Active

Indicates whether adaptive shaping is enabled.

Queue Depth

Current queue depth of the traffic shaper.

Packets

Total number of packets that have entered the traffic shaper system.

Bytes

Total number of bytes that have entered the traffic shaper system.

Packets Delayed

Total number of packets delayed in the queue of the traffic shaper before being transmitted.

Bytes Delayed

Total number of bytes delayed in the queue of the traffic shaper before being transmitted.

Shaping Active

Indicates whether the traffic shaper is active. For example, if a traffic shaper is active, and the traffic being sent exceeds the traffic shaping rate, a "yes" appears in this field.

1 A number in parentheses may appear next to the service-policy output name, class-map name, and match criteria information. The number is for Cisco internal use only and can be disregarded.


Packet Classification Based on Layer 3 Packet Length show policy-map interface Command Example

The following sample output from the show policy-map interface command displays the packet statistics for the Ethernet4/1 interface, to which a service policy called "mypolicy" is attached. The Layer 3 packet length has been specified as a match criterion for the traffic in the class called "class1".


Router# show policy-map interface Ethernet4/1

 Ethernet4/1 

  Service-policy input: mypolicy

    Class-map: class1 (match-all)
       500 packets, 125000 bytes
       5 minute offered rate 4000 bps, drop rate 0 bps
       Match: packet length min 100 max 300
       QoS Set
         qos-group 20
           Packets marked 500

Table 15 describes the significant fields shown in the display.

Table 15 show policy-map interface Field Descriptions—Configured for Packet Classification Based on Layer 3 Packet Length1  

Field
Description

Service-policy input

Name of the input service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets, bytes

Number of packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of packets coming in to the class.

Note If the packets are compressed over an outgoing interface, the improved packet rate achieved by packet compression is not reflected in the offered rate. Also, if the packets are classified before they enter a combination of tunnels (for example, a generic routing encapsulation (GRE) tunnel and an IP Security (IPSec) tunnel), the offered rate does not include all the extra overhead associated with tunnel encapsulation in general. Depending on the configuration, the offered rate may include no overhead, may include the overhead for only one tunnel encapsulation, or may include the overhead for all tunnel encapsulations. In most of the GRE and IPSec tunnel configurations, the offered rate includes the overhead for GRE tunnel encapsulation only.

drop rate

Rate, in kbps, at which packets are dropped from the class. The drop rate is calculated by subtracting the number of successfully transmitted packets from the offered rate.

Match

Match criteria specified for the class of traffic. Choices include criteria such as the Layer 3 packet length, IP precedence, IP DSCP value, MPLS experimental value, access groups, and QoS groups.

QoS Set, qos-group, Packets marked

Indicates that class-based packet marking based on the QoS group has been configured. Includes the qos-group number and the number of packets marked.

1 A number in parentheses may appear next to the service-policy input name, class-map name, and match criteria information. The number is for Cisco internal use only and can be disregarded.


Enhanced Packet Marking show policy-map interface Command Example

The following sample output of the show policy-map interface command shows the service policies attached to a FastEthernet subinterface. In this example, a service policy called "policy1" has been attached. In "policy1", a table map called "table-map1" has been configured. The values in "table-map1" will be used to map the precedence values to the corresponding class of service (CoS) values.

Router# show policy-map interface

 FastEthernet1/0.1 

  Service-policy input: policy1

    Class-map: class-default (match-any)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any 
      QoS Set
        precedence cos table table-map1
          Packets marked 0

Table 16 describes the fields shown in the display.

Table 16 show policy-map interface Field Descriptions—Configured for Enhanced Packet Marking 1

Field
Description

Service-policy input

Name of the input service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets, bytes

Number of the packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of the packets coming into the class.

Match

Match criteria specified for the class of traffic. Choices include criteria such as Precedence, IP differentiated services code point (DSCP) value, Multiprotocol Label Switching (MPLS) experimental value, access groups, and quality of service (QoS) group (set). For more information about the variety of match criteria options that are available, refer to the "Configuring the Modular Quality of Service Command-Line Interface" section in the Cisco IOS Quality of Service Solutions Configuration Guide.

QoS Set

Indicates that QoS group (set) has been configured for the particular class.

precedence cos table table-map1

Indicates that a table map (called "table-map1") has been used to determine the precedence value. The precedence value will be set according to the CoS value defined in the table map.

Packets marked

Total number of packets marked for the particular class.

1 A number in parentheses may appear next to the service-policy input name and the class-map name. The number is for Cisco internal use only and can be disregarded.


Traffic Policing show policy-map interface Command Example

The following is sample output from the show policy-map interface command. This sample displays the statistics for the serial 2/0 interface on which traffic policing has been enabled. The committed (conform) burst (bc) and excess (peak) burst (be) are specified in milliseconds (ms).

Router# show policy-map interface serial2/0

 Serial2/0 

  Service-policy output: policy1 (1050)

    Class-map: class1 (match-all) (1051/1)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: ip precedence 0  (1052)
      police:
          cir 20 % bc 300 ms
          cir 409500 bps, bc 15360 bytes
          pir 40 % be 400 ms
          pir 819000 bps, be 40960 bytes
        conformed 0 packets, 0 bytes; actions:
          transmit 
        exceeded 0 packets, 0 bytes; actions:
          drop 
        violated 0 packets, 0 bytes; actions:
          drop 
        conformed 0 bps, exceed 0 bps, violate 0 bps

    Class-map: class-default (match-any) (1054/0)
      0 packets, 0 bytes
      5 minute offered rate 0 bps, drop rate 0 bps
      Match: any  (1055)
        0 packets, 0 bytes
        5 minute rate 0 bps

In this example, the CIR and PIR are displayed in bps, and both the committed burst (bc) and excess burst (be) are displayed in bits.

The CIR, PIR bc, and be are calculated on the basis of the formulas described below.

Formula for Calculating the CIR

When calculating the CIR, the following formula is used:

CIR percentage specified (as shown in the output from the show policy-map command) * bandwidth (BW) of the interface (as shown in the output from the show interfaces command) = total bits per second

According to the output from the show interfaces command for the serial 2/0 interface, the interface has a bandwidth (BW) of 2048 kbps.

Router # show interfaces serial2/0

Serial2/0 is administratively down, line protocol is down 
  Hardware is M4T 
  MTU 1500 bytes, BW 2048 Kbit, DLY 20000 usec, rely 255/255, load 1/255 

The following values are used for calculating the CIR:

20 % * 2048 kbps = 409600 bps

Formula for Calculating the PIR

When calculating the PIR, the following formula is used:

PIR percentage specified (as shown in the output from the show policy-map command) * bandwidth (BW) of the interface (as shown in the output from the show interfaces command) = total bits per second

According to the output from the show interfaces command for the serial 2/0 interface, the interface has a bandwidth (BW) of 2048 kbps.

Router # show interfaces serial2/0

Serial2/0 is administratively down, line protocol is down  
  Hardware is M4T 
  MTU 1500 bytes, BW 2048 Kbit, DLY 20000 usec, rely 255/255, load 1/255 

The following values are used for calculating the PIR:

40 % * 2048 kbps = 819200 bps


Note Discrepancies between this total and the total shown in the output from the show policy-map interface command can be attributed to a rounding calculation or to differences associated with the specific interface configuration.


Formula for Calculating the Committed Burst (bc)

When calculating the bc, the following formula is used:

The bc in milliseconds (as shown in the show policy-map command) * the CIR in bits per seconds = total number bytes

The following values are used for calculating the bc:

300 ms * 409600 bps = 15360 bytes

Formula for Calculating the Excess Burst (be)

When calculating the bc and the be, the following formula is used:

The be in milliseconds (as shown in the show policy-map command) * the PIR in bits per seconds = total number bytes

The following values are used for calculating the be:

400 ms * 819200 bps = 40960 bytes

Table 17 describes the significant fields shown in the display.

Table 17 show policy-map interface Field Descriptions 

Field
Description

Service-policy output

Name of the output service policy applied to the specified interface or VC.

Class-map

Class of traffic being displayed. Output is displayed for each configured class in the policy. The choice for implementing class matches (for example, match-all or match-any) can also appear next to the traffic class.

packets and bytes

Number of packets (also shown in bytes) identified as belonging to the class of traffic being displayed.

offered rate

Rate, in kbps, of packets coming in to the class.

drop rate

Rate, in kbps, at which packets are dropped from the class. The drop rate is calculated by subtracting the number of successfully transmitted packets from the offered rate.

Match

Match criteria specified for the class of traffic. Choices include criteria such as the Layer 3 packet length, IP precedence, IP differentiated services code point (DSCP) value, Multiprotocol Label Switching (MPLS) experimental value, access groups, and quality of service (QoS) groups. For more information about the variety of match criteria options that are available, refer to the "Configuring the Modular Quality of Service Command-Line Interface" chapter of the Cisco IOS Quality of Service Solutions Configuration Guide.

police

Indicates that traffic policing has been enabled. Display includes the CIR, PIR (in both a percentage of bandwidth and in bps) and the bc and be in bytes and milliseconds. Also displays the optional conform, exceed, and violate actions, if any, and the statistics associated with these optional actions.


Bandwidth Estimation show policy-map interface Command Example

The following sample output from the show policy-map interface command displays statistics for the FastEthernet 0/1 interface on which bandwidth estimates for quality of service (QoS) targets have been generated.

The Bandwidth Estimation section indicates that bandwidth estimates for QoS targets have been defined. These targets include the packet loss rate, the packet delay rate, and the timeframe in milliseconds. Confidence refers to the drop-one-in value (as a percentage) of the targets. Corvil Bandwidth means the bandwidth estimate in kilobits per second.

When no drop or delay targets are specified, "none specified, falling back to drop no more than one packet in 500" appears in the output.

Router# show policy-map interface FastEthernet0/1

 FastEthernet0/1

  Service-policy output: my-policy

    Class-map: icmp (match-all)
      199 packets, 22686 bytes
      30 second offered rate 0 bps, drop rate 0 bps
      Match: access-group 101
      Bandwidth Estimation:
        Quality-of-Service targets:
          drop no more than one packet in 1000 (Packet loss < 0.10%)
          delay no more than one packet in 100 by 40 (or more) milliseconds
            (Confidence: 99.0000%)
        Corvil Bandwidth: 1 kbits/sec

    Class-map: class-default (match-any)
      112 packets, 14227 bytes
      30 second offered rate 0 bps, drop rate 0 bps
      Match: any
      Bandwidth Estimation:
        Quality-of-Service targets:
          <none specified, falling back to drop no more than one packet in 500
        Corvil Bandwidth: 1 kbits/sec

Shaping with HQF Enabled show policy-map interface Command Example

The following sample output from the show policy-map interface command shows that shaping is active (as seen in the queue depth field) with HQF enabled on the serial 4/3 interface. All traffic is classified to the class-default queue.

Router# show policy-map interface serial4/3

 Serial4/3

  Service-policy output: shape

    Class-map: class-default (match-any)
      2203 packets, 404709 bytes
      30 second offered rate 74000 bps, drop rate 14000 bps
      Match: any
      Queueing
      queue limit 64 packets
      (queue depth/total drops/no-buffer drops) 64/354/0
      (pkts output/bytes output) 1836/337280
      shape (average) cir 128000, bc 1000, be 1000
      target shape rate 128000
        lower bound cir 0,  adapt to fecn 0

      Service-policy : LLQ

        queue stats for all priority classes:
         
          queue limit 64 packets
          (queue depth/total drops/no-buffer drops) 0/0/0
          (pkts output/bytes output) 0/0

        Class-map: c1 (match-all)
          0 packets, 0 bytes
          30 second offered rate 0 bps, drop rate 0 bps
          Match: ip precedence 1
          Priority: 32 kbps, burst bytes 1500, b/w exceed drops: 0

        Class-map: class-default (match-any)
          2190 packets, 404540 bytes
          30 second offered rate 74000 bps, drop rate 14000 bps
          Match: any

          queue limit 64 packets
          (queue depth/total drops/no-buffer drops) 63/417/0
          (pkts output/bytes output) 2094/386300

Related Commands

Command
Description

compression header ip

Configures RTP or TCP IP header compression for a specific class.

drop

Configures a traffic class to discard packets belonging to a specific class.

match fr-dlci

Specifies the Frame Relay DLCI number as a match criterion in a class map.

match packet length (class-map)

Specifies the length of the Layer 3 packet in the IP header as a match criterion in a class map.

police

Configures traffic policing.

police (percent)

Configures traffic policing on the basis of a percentage of bandwidth available on an interface.

police (two rates)

Configures traffic policing using two rates, the CIR and the PIR.

policy-map

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

random-detect ecn

Enables ECN.

shape (percent)

Specifies average or peak rate traffic shaping on the basis of a percentage of bandwidth available on an interface.

show frame-relay pvc

Displays statistics about PVCs for Frame Relay interfaces.

show interfaces

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

show policy-map

Displays the configuration of all classes for a specified service policy map or all classes for all existing policy maps.

show policy-map class

Displays the configuration for the specified class of the specified policy map.

show table-map

Displays the configuration of a specified table map or of all table maps.

table-map (value mapping)

Creates and configures a mapping table for mapping and converting one packet-marking value to another.