match rtp in a class-map

[schwarzenbachcyb]

I can match rtp traffic in a class-map in two different ways:

class-map match-any CMP-VOIP
 match ip rtp 16384 16383

and

class-map match-any CMP-VOIP
 match application rtp

Is there any difference between them? Is one better than the other?

Does both also match IPv6 rtp traffic? Or is this maybe the different between this two commands?

[Joseph W. Doherty]

The latter, I believe, is using NBAR, and if that's correct, there's various implementations of NBAR that can vary in how they determine if a packets belongs to one of the protocols that implementation of NBAR "knows".

In general, NBAR might just be a "pretty face" for a match that could be done as well with a simple ACL ACE or it might encompass deep packet inspection.  To determine what criteria NBAR uses for matching, you need to find documentation on your particular implementation.