From: DaveW (kapsi1911@hotmail.com)
Date: Mon Apr 18 2005 - 00:23:17 GMT-3
Mani,
The "match ip rtp 16384 16383" command matches even UDP ports in the range
of 16384 - 32767. If another (non-voice) application happened to use UDP and
ports in this range, it would also match.
The "match protocol rtp <audio>|<video>|<payload-type>" is a granular way to
classify RTP streams. NBAR will look at the RTP header payload type values.
So this would allow you to differentiate between audio (and video) CODECS.
It's also a way to MAKE SURE you are classifying audio (VOIP) traffic. You
can always just use the "match protocol rtp audio" command alone if you
don't want to get into specifying payload types. This will catch most of the
well known audio CODECS like G711, G729, etc... It catches payload types
0-23.
Here is a link to the assigned payload type values:
http://www.iana.org/assignments/rtp-parameters
I would think you're access-list would accomplish the same thing as the
"match ip rtp 16384 16383" command but would also match odd number ports in
the 16384 - 32767 range, so you would also be classifying control traffic
(RTCP). I would lose the "permit tcp any any eq 1720" line though. I'm
pretty sure we don't have to worry about H.323/H.225 for the R&S lab. I
personally think the best method to match VOIP traffic traveling from one
network to another would be to use a combination of NBAR and an access-list
which matches on the source/destination networks:
class-map match-all VOIP
match protocol rtp audio
match access-group name NETWORKS
DAve
----- Original Message -----
> From: "mani poopal" <mani_ccie@yahoo.com>
> To: <ccielab@groupstudy.com>
> Sent: Sunday, April 17, 2005 9:38 PM
> Subject: voice traffic definition
>
>
> > Hi Guys,
> >
> > I have seen scenarios asking to define some variables(bandwidth, ip
> precedence, next hop etc) for voice traffic. What is the syntax of
> defining voice traffic.
> > (A.)
> > permit tcp any any eq 1720
> > permit udp any any range 16384 32767
> >
> > (B.)
> > class-map VOICE
> > match protocol rtp<--Is it voice traffic or rtp traffic
> >
> > (C.)
> > class-map VOICE
> > match ip rtp priority 16384 16387
> >
> > I think only A, C define voice traffic(is it same as voice over ip), and
> when they ask for voice traffic going from some network to anothe network
we
> have to use option A. When they don't specify source/destination, we can
go
> with option B.
> > Guys what is the difference between match protcol rtp and match ip rtp
> priority 16384 16387, any insights in to above three commands with
> explanations are appreciated.
> >
> > thanks
> >
> > Mani
> >
> >
> >
> > B.ENG,A+,CCNA,CCNP,CCNP-VOICE, CSS1,CNA,MCSE
> > (416)431 9929
> > MANI_CCIE@YAHOO.COM
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