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Joe Harris, CCIE No. 6200 (R&S, Security & SP) is a Systems Engineer with Cisco Systems® specializing in Security. In addition to authoring Cisco Network Security Little Black Book, Joe has also been a technical reviewer for several Cisco Press publications and written articles, white papers, and presentations on various security technologies. He also assists various Certification Partners by beta testing their newest CCIE certification workbooks and has been recognized by Cisco as an SE Wall of Fame award winner.

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Modular QoS CLI Class-Map Limitations

November 26th, 2007 • Related • Filed Under

I received a question from a customer that I thought I would post up….

Question:
Hi Joe, I was wondering if there are any limitations on the maximum number of class-maps per policy-map on a 2800 series ISR. I thought I saw a newsgroup listing indicating that the limit of 256 was to be lifted, however this thread is dated. Can you provide me with a definitive answer as it stands with IOS 12.4? 

Answer:
I tried with 12.4(16) and cannot configure more than 255. 

R2(config-pmap)#do sh ver | inc Ver
Cisco IOS Software, 2800 Software (C2800NM-ADVIPSERVICESK9-M), Version 12.4(16), RELEASE SOFTWARE (fc1)
ROM: System Bootstrap, Version 12.4(1r) [hqluong 1r], RELEASE SOFTWARE (fc1)
R2(config-pmap)#
R2(config-pmap)#class TEST_485    
Max limit of 255 classes in a policy reached
R2(config-pmap)#

There Are 3 Responses So Far. »

  1. Gravatar

    Comment by shef on 26 November 2007:

    Hm…. I cannot image 256 class-maps in policy-map, for what purpose? :/

  2. Gravatar

    Comment by Joe Harris on 28 November 2007:

    Hierarchical queuing and the ability to create nested policies…as increasingly providers are handing customers services using Ethernet termination. A 2Mb circuit may be presented now as a 10Mb or 100Mb Ethernet RJ45 and we will need to rate this interface down to 2Mb and then perform queuing within this 2Mb.

  3. Gravatar

    Comment by Joe Harris on 28 November 2007:

    As a follow-up here is an example configuration related to my last post that should make it’s uses clear:

    #Cust1-classes configuration
    R2(config)# policy-map cust1-classes
    R2(config-pmap)# class gold
    R2(config-pmap-c)# bandwidth percent 50
    R2(config-pmap)# class silver
    R2(config-pmap-c)# bandwidth percent 20
    R2(config-pmap)# class bronze
    R2(config-pmap-c)# bandwidth percent 15
    !
    #Cust2-classes configuration
    R2(config)# policy-map cust2-classes
    R2(config-pmap)# class gold
    R2(config-pmap-c)# bandwidth percent 30
    R2(config-pmap)# class silver
    R2(config-pmap-c)# bandwidth percent 15
    R2(config-pmap)# class bronze
    R2(config-pmap-c)# bandwidth percent 10
    !
    #Cust Policy and QoS Features Config
    R2(config)# policy-map cust-policy
    R2(config-pmap)# class cust1
    R2(config-pmap-c)# shape average 384000
    R2(config-pmap-c)# service-policy cust1-classes
    R2(config-pmap)# class cust2
    R2(config-pmap-c)# shape peak 512000
    R2(config-pmap-c)# service-policy cust2-classes
    !
    R2(config-pmap-c)# interface Serial 2/1
    R2(config-if)# service out cust-policy

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