[c-nsp] QoS best practices

[Tassos Chatzithomaoglou]

Brian Turnbow wrote on 15/10/2009 12:55:
> 
> 
>> The 3560 buffering discussion has reminded me:
> 
>> It's not hard to find documentation on configuring QoS, but I haven't
>> yet found any "best practices" reagarding how to specifically classify,
> <i.e. what traffic goes in what queue with what DSCP/CoS marking.
> 
> RFC 4594 is a good start
> 
>> For VoIP it seems there are some notes, so it seems very "best
> practice"
>> to use EF for voice traffic and AF31 for signaling. But what about all
>> other traffic?
> 
> This is cisco's. I recently got into a discussion with another supplier
> about AF31
> As a Cisco shop we used AF31 for VoIP signalling, they used CS5 as per
> RFC4594. So 
> Even here it is not so clear. 
> 

Cisco has changed it to CS3.

===
The QoS Baseline recommends marking Call-Signaling to CS3. However, currently most Cisco IP
Telephony products mark Call-Signaling to AF31. A marking migration from AF31 to CS3 is under way
within Cisco, but in the interim it is recommended that both AF31 and CS3 be reserved for
Call-Signaling and that Locally-Defined Mission-Critical Data applications be marked to a temporary
placeholder non-standard DSCP, such as 25. Upon completion of the migration, the QoS Baseline
marking recommendations of CS3 for Call-Signaling and AF31 for Locally-Defined Mission-Critical
Data applications should be used. These marking recommendations are more in line with RFC 2474 and
RFC 2597.
===

--
Tassos