Codec G711ULAW

[Hieu Cao]

I've been doing some researching, I am having difficulty of determining of whether the codec G711ULAW (or any other codec for that matter) is part of voice protocol or signaling so that I can build appropriate QoS statement for it (DSCP EF for Voice and DSCP AF31 for Signaling).

Please help me to clarify it, or perhaps you can point me to some reference.

Thanks!

Hieu

[thisisshanky]

Hieu,

Not sure what exactly you are looking for here.

Call signalling takes care of negotiating between the end points as to what codec to use. For example, if the call uses h323 signalling, h245 takes care of codec negotiation. Now the end points use the negotiated codec to encode the voice signal into packet.

So in case of H323 protocol, apply af31 (this has changed in case of callmanager, it is cs3) to port 1720. and EF to RTP. For SCCP based phone, apply af31 (cs3) to SCCP (TCP port 2000) and EF to RTP.

[Hieu Cao]

Sankar,

Thanks for the clarification and quick response. It's very helpful.

Thanks!

Hieu