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Configuring CoS on an MPLS Provider Edge Switch Using Circuit Cross-Connect

You can use class of service (CoS) within MPLS networks to prioritize certain types of traffic during periods of congestion. This topic describes configuring CoS components on a provider edge (PE) switch that is using MPLS over circuit-cross connect (CCC).


If you are using MPLS over CCC, you can use only one DSCP or IP precedence classifier and only one IEEE 802.1p classifier on the CCC interfaces.

This procedure is for creating a custom DSCP classifier and a custom EXP rewrite rule on the ingress PE. It also includes enabling a policer on the label-switched path (LSP) of the ingress PE to ensure that the amount of traffic forwarded through the LSP never exceeds the requested bandwidth allocation.

This topic includes:

Configuring CoS

To configure CoS on a provider edge switch:

  1. Import the default DSCP classifier classes to the custom DSCP classifier that you are creating:
  2. Add the expedited-forwarding class to this custom DSCP classifier, specifying a loss priority and code point:
  3. Specify the values for the custom EXP rewrite rule, e1:
  4. Bind the DSCP classifier to the CCC interface:

Configuring an LSP Policer

To configure an LSP policer:

  1. Specify the number of bits per second permitted, on average, for the policer, which will later be applied to the LSP:
  2. Specify the maximum size permitted for bursts of data that exceed the given bandwidth limit for this policer:
  3. Discard traffic that exceeds the rate limits for this policer:
  4. To reference the policer, configure a filter term that includes the policer action:
  5. Apply the filter to the LSP:

You can also configure schedulers and shapers as needed. See Defining CoS Schedulers and Scheduler Maps (CLI Procedure).