when i read the RFC-Recommended Values for Marking, which is in Cisco QOS design Guide docments...
i noticed that COS 4, IPP 4 andDSCP AF41recommended for Video payload
and Cos 3, IPP 3 and DSCP CS3 recommended for Voice/video signaling
my question is, why we don't use AF31, AF32, or AF33 for those type of traffic instead of CS3, in other words why it used CS for that traffic and not AF as for the others that are mentioned in the table.
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
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.
So, AF31 will be used for Locally-Defined Mission-Critical Data. NB: I have not looked at the two RFCs, but I would guess AF32 and AF33 would be used for different drop priorities for such traffic. Signaling you want to avoid dropping at all.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...