class-map with DSCP and to/from specific IP address(es)

Unanswered Question
Dec 26th, 2009

Hi forum,

I'd like to create a QoS class/policy map for VoIP traffic to steer the traffic to a priority queue.  I'd like to configure this such that traffic with DSCP EF *and* to/from specific IP addresses are matched.  It isn't clear to me whether this is possible.  If I create a class-map with multiple entries, such as:

class-map VOIP
  match dscp ef

  match ip address ACL_FOR_VOIP

... does that match traffic with DSCP EF and matching the ACL?  Or does is match either traffic with DSCP EF, or traffic matching the ACL?

I couldn't find that distinction specifically stated in the documentation.

Thanks in advance...

I have this problem too.
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Jon Marshall Mon, 12/28/2009 - 15:55

schinatti wrote:

Hi forum,

I'd like to create a QoS class/policy map for VoIP traffic to steer the traffic to a priority queue.  I'd like to configure this such that traffic with DSCP EF *and* to/from specific IP addresses are matched.  It isn't clear to me whether this is possible.  If I create a class-map with multiple entries, such as:

class-map VOIP
  match dscp ef

  match ip address ACL_FOR_VOIP

... does that match traffic with DSCP EF and matching the ACL?  Or does is match either traffic with DSCP EF, or traffic matching the ACL?

I couldn't find that distinction specifically stated in the documentation.

Thanks in advance...

There is an option with the class-map command to specify either "match-all" or "match-any" eg.

class-map match-all VOIP - means all the match statements must match so in your case the packet would have to

1) be marked with DSCP value ef

and

2) match a permit entry in the ACL_FOR_VOIP acl

or

class-map match-any VOIP - means only one of the match statements has to be met so in your case the packet could be DSCP ef because it matches the "match dscp ef" but the source and destination address might not be in ACL_FOR_VOIP.

So if you want to match packets that have DSCP ef and source/destination IPs in your ACL_FOR_VOIP you want "match-all"

If you don't specify the "match-all" or "match-any" keyword then the default is "match-all" so your class-map should do what you want.

Jon

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