LARTC - Mar 2005 - QoS and VoIP

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Hi all,

I made some filters on tc to match the VoIP traffic based on RTP packet
RFC 1889.

The only patern I found was the rtp version and the payload type wich
identify the codec. The u32 rules are:

- - match ip protocol 0x11 0xff -> UDP
- - match u8 0x80 0xc0 at 28 -> RTP version 2 (two fists bits
''10'' of the
byte)
- - match u8 0x61 0x7f at 29 -> Codec number 97 (seven bits of the byte
without the first bit)

This with a iptables marking the packet with dport and sport > 1024 work
fine. But if I have more codecs I need more filter rules.

Some idea to match better?

Thanks.

x-arnie
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Alessandro Oliveira Ungaro wrote:
>
> I made some filters on tc to match the VoIP traffic based on RTP packet
> RFC 1889.
>
> The only patern I found was the rtp version and the payload type wich
> identify the codec. The u32 rules are:

Interesting question! 

This is probably a good questino to take to the l7 (layer 7) mailing 
list as well.  See if they have some stuff already...

Sorry, no practical better suggestions from me though...

Ed W