Tagged: Cat6500

Cat6500-E Sup2T Etherchannel Egress QoS

Cisco is now using a more MQC like QoS configuration with the Sup2T Supervisor Engine which is called C3PL (Cisco Common Classification Policy Language). C3PL is not only used for QoS configuration but also for other tasks:

Cisco Common Classification Policy Language is a structured replacement for feature-specific configuration commands. C3PL allows you to create traffic policies based on events, conditions, and actions

If you know MQC you´ll find it more confortable to use the new C3PL instead of the old mls QoS configuration but the Cat6500 architecture still plays a role. If you want to configure egress QoS on an etherchannel, you have to configure the egress queuing policies on the physical port members of the etherchannel, it cannot be configured on the logical Etherchannel interface. If you try to, you´ll get an error message like this:

MQC features are not supported in output direction for this interface

The documentation for this can be found in the Cat6500 Supervisor 2T Qos Design At-a-Glance  Guide.


As explained above you have to configure egress queueing policies on the physical port members to make use of egress queueing policies on an etherchannel:

class-map type lan-queuing PRIORITY-QUEUE
match dscp ef
policy-map type lan-queueing EGRESS-QUEUING-PHYSICAL
class class-default
int te1/1
 channel-group 10 mode active
 service-policy type lan-queueing output EGRESS-QUEUING-PHYSICAL
int te1/2
 channel-group 10 mode active
 service-policy type lan-queueing output EGRESS-QUEUING-PHYSICAL

VSS and QoS on Cat6500 SUP2T

I really don’t like QoS on Cisco Switches, its too complicated and totally depends on the chassis or even on the line card in chassis based switches. What made things worse is how QoS and VSS is implemented on the Cat6500 (and documented). I recently had to create a QoS design for a customer which had VSS on Cat6500 with SUP2T and 16-port 10GE line cards. The VSL Links were on the SUP using the two 10GE ports and I had to configure QoS towards the WAN on two out of the three 1GE ports on the SUP.

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