mqc , class map class-default

[sarahr202]

Hi everybody.

Please consider the following config:

R1(config)# class-map MUSIC

R1(config-cmap)# match protocol kazzaa2

R1(Config)# policy-map TSHoot-EXAMPLE

R1(config-pmap)# class MUSIC

R1(config-pmap-c)# police 32000

R1(config)# int s0/0

R1(config-if)# service-policy output TSHOOT-EXAMPLE

My book says cisco created a default class map named class-default which categorizes all the traffic not matched by any defined class maps.

Let say we have some packets carrying e mail traffics. These packets are matched by default class map.  What will happen next?  We dont have any policy defined for these packets matched by default class map so what will happen to these packets?

thanks and have a great day.

[John Blakley · Accepted solution]

Sarah,

Anything that doesn't match a class in a policy map will match the class-default class. (Not seen, but it's configurable.) Anything that matches under the class-default class will get best effort delivery by default, but you can configure fair-queueing and tail drop under this class as well. That helps for traffic that does get put into this class.

HTH,

John

[sarahr202]

Thanks John

[Joseph W. Doherty]

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Posting

To expand a little on John's posting, implicit (not explicity defined) class-default behavior will vary a bit based on other explictly defined classes and the IOS version, for example pre-HQF and post-HQF QoS.