QOS MARKING

[hellzx]

ip access-list ext 100
permit tcp any any lt 1024
permit tcp any lt 1024 any

class-map tcp
match access-group 100
class-map others
match not class-map tcp

policy-map tst
class tcp
set ip prec 4
class others
set ip prec 0

in f0/0
service-policy out tst



ip access-list ext 100
permit tcp any any lt 1024
permit tcp any lt 1024 any

class-map tcp
match access-group 100

policy-map tst
class tcp
set ip prec 4
class class-default
set ip prec 0

in f0/0
service-policy out tst


What is the difference between the two configurations?

 

[Minue]

Hello
The match not command is a bit tricky.I could be wrong, but in this case the top example the "match not class-map tcp" is not applicable,it's just saying not to do anything with the "class-map tcp" but it will not set the other traffic to "prec 0".The other traffic will automatically have no precedence because no policy is applied.

Regards

 

[maheick]

Your match criteria is essentially the same for both criteria. The only difference might be that in the first, you will consume more router resources by creating two class maps that require an additional inspection of all packets.

In the second configuration, you are relaying on the default behaviour of the router, which basically says that if there isn't a class map defined that matches any characteristics of the traffic, it will fall into the default class.