Punt Policing and Monitoring

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Updated:April 8, 2013

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Punt Policing and Monitoring

Punt Policing and Monitoring

Punt policing protects the Route Processor (RP) from having to process noncritical traffic, which increases the CPU bandwidth available to critical traffic. Traffic is placed into different CPU queues based on various criteria. The Punt Policing and Monitoring feature allows you to police the punt rate on a per-queue basis.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

Information About Punt Policing and Monitoring

Overview of Punt Policing and Monitoring

Packets received on an interface are punted to the Router Processor (RP) for various reasons. Some examples of these various reasons include, unicast and multicast control plane traffic that are destined for a routing protocol process running on the RP, and IP packets that generate Internet Control Message Protocol (ICMP) exceptions such as a Time to live (TTL) expiration. The RP has a limited capacity to process the punted packets, and while some of them are critical for the router operation and should not be dropped, some can be dropped without impacting the router operation.

Punt policing frees the RP from having to process noncritical traffic. Traffic is placed in queues based on various criteria, and you can configure the maximum punt rate for each queue which allows you to configure the system so that packets are less likely to be dropped from queues that contain critical traffic.


Note

Traffic on certain CPU queues could still be dropped, regardless of the configured punt rate, based on other criteria such as the queue priority, queue size, and traffic punt rate.

How to Configure Punt Policing and Monitoring

Configuring Punt Policing


Note

Traffic on a specific CPU queue may be dropped irrespective of the configured maximum punt rate, based on the queue priority, queue size, and the configured traffic punt rate.

Perform this task to specify the maximum punt rate on the specified queue.
SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    platform punt-police queue queue-id max-punt-rate max-burst-rate

    4.    end


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 platform punt-police queue queue-id max-punt-rate max-burst-rate


    Example: 
    Router(config)# platform punt-police queue 20 9000 10000
     

    Enables punt policing on a queue, and specifies the maximum punt rate and burst rate on a per-queue basis.

     
    Step 4 end


    Example: 
    Router(config-cp)# end
     

    (Optional) Returns to privileged EXEC mode.

     

    Verifying Punt Policing

    Verifying Queue-Based Punt Policing

    Use the show platform software infrastructure punt statistics command to verify that punt policing is configured for a queue. If the feature is configured on your interface, the command output displays punt police statistics: 

    Router# show platform software infrastructure punt statistics
UEA Punt Statistics

Global drops : 0

 Queue Name             | Rx count                  |  Drop count
------------------------+---------------------------+-----------------------
 SW FORWARDING Q        | 0                         | 0                        
 ROUTING PROTOCOL Q     | 0                         | 0                        
 ICMP Q                 | 0                         | 0                        
 HOST Q                 | 57115                     | 0                        
 ACL LOGGING Q          | 0                         | 0                        
 STP Q                  | 0                         | 0                        
 L2 PROTOCOL Q          | 6571                      | 0                        
 MCAST CONTROL Q        | 208839                    | 0                        
 BROADCAST Q            | 4                         | 0                        
 REP Q                  | 0                         | 0                        
 CFM Q                  | 0                         | 0                        
 CONTROL Q              | 0                         | 0                        
 IP MPLS TTL Q          | 0                         | 0                        
 DEFAULT MCAST Q        | 0                         | 0                        
 MCAST ROUTE DATA Q     | 0                         | 0                        
 MCAST MISMATCH Q       | 0                         | 0                        
 RPF FAIL Q             | 0                         | 0                        
 ROUTING THROTTLE Q     | 87                        | 0                        
 MCAST Q                | 0                         | 0                        
 MPLS OAM Q             | 0                         | 0                        
 IP MPLS MTU Q          | 0                         | 0                        
 PTP Q                  | 0                         | 0                        
 LINUX ND Q             | 0                         | 0                        
 KEEPALIVE Q            | 0                         | 0                        
 ESMC Q                 | 0                         | 0                        
 FPGA BFD Q             | 0                         | 0                        
 FPGA CCM Q             | 0                         | 0                        
 FPGA CFE Q             | 0                         | 0                        
 L2PT DUP Q             | 0                         | 0

    Verifying Punt Policing Statistics

    Use the show platform hardware pp active infrastructure pi npd rx policer command to display the punt policing statistics for all queues: 

    Router# show platform hardware pp active infrastructure pi npd rx policer 
PUNT POLICER

Ring |          Queue Name |           Punt rate |          Burst rate
-----+---------------------+---------------------+--------------------
 0   |     SW FORWARDING Q |                 500 |                1000 
 1   |  ROUTING PROTOCOL Q |                 500 |                1000 
 2   |              ICMP Q |                 500 |                1000 
 3   |              HOST Q |                1000 |                2000 
 4   |       ACL LOGGING Q |                 500 |                1000 
 5   |               STP Q |                3000 |                6000 
 6   |       L2 PROTOCOL Q |                1000 |                2000 
 7   |     MCAST CONTROL Q |                1000 |                2000 
 8   |         BROADCAST Q |                 500 |                1000 
 9   |               REP Q |                3000 |                6000 
10   |               CFM Q |                3000 |                6000 
11   |           CONTROL Q |                1000 |                2000 
12   |       IP MPLS TTL Q |                1000 |                2000 
13   |     DEFAULT MCAST Q |                 500 |                1000 
14   |  MCAST ROUTE DATA Q |                 500 |                1000 
15   |    MCAST MISMATCH Q |                 500 |                1000 
16   |          RPF FAIL Q |                 500 |                1000 
17   |  ROUTING THROTTLE Q |                 500 |                1000 
18   |             MCAST Q |                 500 |                1000 
19   |          MPLS OAM Q |                1000 |                2000 
20   |       IP MPLS MTU Q |                 500 |                1000 
21   |               PTP Q |                3000 |                6000 
22   |          LINUX ND Q |                 500 |                1000 
23   |         KEEPALIVE Q |                1000 |                2000 
24   |              ESMC Q |                3000 |                6000 
25   |          FPGA BFD Q |                3000 |                6000 
26   |          FPGA CCM Q |                3000 |                6000 
27   |          FPGA CFE Q |                3000 |                6000 
28   |          L2PT DUP Q |                4000 |                8000

    Configuration Examples for Punt Policing and Monitoring

    Example: Configuring Punt Policing

    The following example shows how to enables punt-policing, set the maximum punt-rate to 9000 bps, and set the maximum burst-rate to 10000 bps, on queue 20: 

    Router# enable
Router# configure terminal
Router(config)# platform punt-police queue 20 9000 10000

    Additional References

    Related Documents

    Related Topic

    Document Title

    QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

    Cisco IOS Quality of Service Solutions Command Reference

    Traffic marking

    “Marking Network Traffic” module

    Traffic policing

    “Traffic Policing” module

    Traffic policing and shaping concepts and overview information

    “Policing and Shaping Overview” module

    Modular quality of service command-line interface (MQC)

    “Applying QoS Features Using the MQC” module

    Standards

    Standard

    Title

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    —

    MIBs

    MIB

    MIBs Link

    None

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

    http:/​/​www.cisco.com/​go/​mibs

    RFCs

    RFC

    Title

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    Technical Assistance

    Description

    Link

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    http:/​/​www.cisco.com/​cisco/​web/​support/​index.html

    Feature Information for Punt Policing and Monitoring

    The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

    Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/​go/​cfn. An account on Cisco.com is not required.

    Table 1 Feature Information for Punt Policing and Monitoring

    Feature Name

    Releases

    Feature Information

    Punt Policing and Monitoring

    Cisco IOS XE Release 3.5S

    The Punt Policing and Monitoring feature allows you to specify a maximum punt rate on a per-queue basis.

    For Cisco IOS XE Release 3.5S, this feature was implemented on Cisco ASR 903 Router.

    The following command was introduced: platform punt-police queue

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