On 05/21/2011 09:24 AM, Juha Heinanen wrote:

this is not really a question for sip proxy mailing list. you need to consult your sip ua mailing list if any.

....more like whatever 'engine' is processing the RTP. Ptime states the sample size (20ms / 30ms)

Jeremy McNamara

On 05/22/2011 03:34 PM, hala alramli wrote:

i have a sip gate provider that accept ptime 20 but my sever send ptime 30 how to change or force it to send 20=

Yes, but what I think others are trying to tell you with their replies is that this is not an appropriate task for a SIP proxy. One cannot simply alter SDP payloads mid-stream in this precise way; it is up to the endpoints to negotiate a mutually suitable ptime. The SIP proxy deals with signaling only.

If the proxy modifies the ptime attribute in the SDP offer of A and passes it onto B, and B sends an answer agreeing on a different ptime than A sent, this will cause either undefined or otherwise undesirable behaviour in A. Do you see the problem? A proxy cannot just force issues that are fundamentally at the discretion of the two UAs and are up to them to negotiate amongst themselves.

You need to set the media/bearer side of your installation (i.e. your media gateway) to support 20 ms ptime, and that's all there is to it.