[SR-Users] change ptime problem

[Alex Balashov]

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.

-- 
Alex Balashov - Principal
Evariste Systems LLC
260 Peachtree Street NW
Suite 2200
Atlanta, GA 30303
Tel: +1-678-954-0670
Fax: +1-404-961-1892
Web: http://www.evaristesys.com/