QoS Class-maps

[kimtoovey]

Trying to understand the class-default for marking

I have the concept of Identify traffic with ACLs

Classify traffic for marking with class-maps

Mark traffic with policy-maps

the policy-map will always have a default-class for unaccounted traffic in the policy-maps

what I don't quite understand is that the there is not a class-map class-default

when servicing the "policy" the class-maps are referenced with "class A" "class B" "class class-default"

when looking for the matches on class class-default there is no reference class-map to go to....

I figured I have to accept this logic means if  traffic was not specifically matched by the collection of class-maps in the config the IOS can assume the traffic would have been/is class-default.

i had put a config together to classify certain traffic as CS0, like SNMP... i wanted to force traffic there as well as having all unaccounted traffic being classified CS0.

but from what i read if i don't have snmp matched in any class-map in the config then this traffic would find itself in

policy-map XXX

     class class-default

     set ip precedence 0

even though class-default does not exist as class-map class-default

[cadet alain]

Hi,

You want to mark some traffic as CS0? and then count that traffic? but you won't know which traffic had CS0 imposed or was natively IPP 0 like all data traffic not specifically marked.

the class class-default exists just do a show class-map and you'll see it, it is the IOS which creates it.

Doing a show policy-map interface will show you which class-map was matched.