CoS configuration Clarification - set-mpls-exp-imposition-transmit

[amr-abdelhamid]

Dear Community Members,

Below is CoS configuration extracted from the PE router to which one of our customers is connected to. I need clarification on the "Class-default" configuration. Based on the configuration below, is the default class being given a higher priority than  the EF class by setting its EXP value to "5" ?

policy-map ##############-###########
description #################################################
  class pe_mgmt_bun_input
    police 240000 15000 30000 conform-action set-mpls-exp-imposition-transmit 6 exceed-action set-mpls-exp-imposition-transmit 2 violate-action set-mpls-exp-imposition-transmit 2
  class pe_ef_input
    police 832000 4000 4000 conform-action set-mpls-exp-imposition-transmit 4 exceed-action drop violate-action drop
  class pe_af3_in_input
    police 248000 17000 34000 conform-action set-mpls-exp-imposition-transmit 6 exceed-action set-mpls-exp-imposition-transmit 2 violate-action set-mpls-exp-imposition-transmit 2
  class pe_af3_out_input
    police 8000 8000 8000 conform-action set-mpls-exp-imposition-transmit 2 exceed-action set-mpls-exp-imposition-transmit 2 violate-action set-mpls-exp-imposition-transmit 2
  class pe_af2_in_input
    police 15536000 139000 278000 conform-action set-mpls-exp-imposition-transmit 6 exceed-action set-mpls-exp-imposition-transmit 2 violate-action set-mpls-exp-imposition-transmit 2
  class pe_af2_out_input
    police 8000 8000 8000 conform-action set-mpls-exp-imposition-transmit 2 exceed-action set-mpls-exp-imposition-transmit 2 violate-action set-mpls-exp-imposition-transmit 2
  class class-default
    police 8000 8000 8000 conform-action set-mpls-exp-imposition-transmit 5 exceed-action set-mpls-exp-imposition-transmit 5 violate-action set-mpls-exp-imposition-transmit 5

[Federico Olivieri]

Hi,

class-default get together all remaining traffic not classified under the policy-map (generally it is used for the BestEffort traffic - all remaining application).

Best practice want that MPLS EXP is used for real time traffic (voice, video, interactive video). However, you don't know how the ISP treats the EXP 5 within his cloud. Perhaps he decided to use EXP 5 to identifies BE traffic as "scavenger" traffic (deducible from the same actions taken in case of conform/exceed/violate)

Federico