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Configuring CoS on an MPLS Provider Edge Switch Using IP Over MPLS

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 IP Over MPLS.

This task describes how to create a custom DSCP classifier and a custom EXP rewrite rule on the ingress PE switch. It includes configuring a policer firewall filter and applying it to the customer-edge interface of the ingress PE switch. The policer firewall filter ensures that the amount of traffic forwarded through the MPLS tunnel never exceeds the requested bandwidth allocation.

Before you begin, configure the basic components for an MPLS network:

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 a forwarding class to this custom DSCP classifier and specify a loss priority and code point:
  3. Specify the values for the custom EXP rewrite rule, e1:
  4. On EX8200 switches only, bind the custom EXP rewrite rule to the interface:

Configuring an LSP Policer

To configure an LSP policer:


You cannot configure LSP policers on EX8200 switches. EX8200 switches do not support LSP policers.

  1. Specify the number of bits per second permitted, on average, for the firewall policer, which will later be applied to the customer-edge-interface:
  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 customer-edge interface:

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