Hmmm..have you changed the UACs on both side or at least the one that is problematic, like Juha said. 

In the codec negotiation I see
a=rtpmap:18 G729/8000 from pjmedia
and 
a=rtpmap:18 G729/8000/1 from VoIPSip/Switch

I'm not sure that this channel info plays much role here because according to rfc it could be omitted if its 1 and no extra params are in the string. But I don't know if this could cause the other UAC to behave abnormally.

you can also confirm if this is Server side issue or UAC side issue by taking a full size tcpdump on ther server for this particular call and hear the call using wireshark. A faulty client side behaviour can be identified if the audio on both sides is ok on server. 

On Mon, Oct 10, 2011 at 2:18 AM, Austin Einter <austin.einter@gmail.com> wrote:
Hi All
Thanks for your kind answer.
 
The call flow looks as below
I have two doubts here
 
1. My UA is just behind the Modem, and in Kamailio config file I have enabled WITH_NAT, will this lead to any kind of problem
 
2.  In kamailio proxy I am using force_rtp_proxy and unforce_rtp_proxy instead of rtpproxy_offer/rtpproxy_answer. Not sure whats the corresponding api for unforce_rtp_proxy.
will this lead to any issues.
 
Regards
Austin.

INVITE sip:919731573290@134.121.32.130:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.1.2:53489;rport;branch=z9hG4bKPj0052793130024dda88418cf7a392b7ae
Max-Forwards: 70
From: sip:austin@134.121.32.130;tag=8c2e350c064e417c96bda1378470fd46
To: sip:919731573290@134.121.32.130
Contact: <sip:austin@192.168.1.2:53489;ob>
Call-ID: b637fa62393a45a0a58633c1a8f43a86
CSeq: 14417 INVITE
Route: <sip:134.33.8.138:5060;lr>
Allow: PRACK, INVITE, ACK, BYE, CANCEL, UPDATE, SUBSCRIBE, NOTIFY, REFER, MESSAGE, OPTIONS
Supported: replaces, 100rel, timer, norefersub
Session-Expires: 1800
Min-SE: 90
User-Agent: VoIP Client v1.01
Proxy-Authorization: Digest username="austin", realm="VoipSwitch", nonce="131819433109160428210053141040", uri="sip:919731573290@134.121.32.130:5060", response="935c3130fe07e2413ccf127d5fb6b9d1"
Content-Type: application/sdp
Content-Length:   271
 
v=0
o=- 3527202931 3527202931 IN IP4 192.168.1.2
s=pjmedia
c=IN IP4 192.168.1.2
t=0 0
a=X-nat:0
m=audio 4000 RTP/AVP 18 4 96
a=rtcp:4001 IN IP4 192.168.1.2
a=rtpmap:18 G729/8000
a=rtpmap:4 G723/8000
a=sendrecv
a=rtpmap:96 telephone-event/8000
a=fmtp:96 0-15
 
SIP/2.0 100 trying
Via: SIP/2.0/UDP 192.168.1.2:53489;rport=13341;branch=z9hG4bKPj0052793130024dda88418cf7a392b7ae;received=122.178.237.67
From: sip:austin@134.121.32.130;tag=8c2e350c064e417c96bda1378470fd46
To: sip:919731573290@134.121.32.130
Call-ID: b637fa62393a45a0a58633c1a8f43a86
CSeq: 14417 INVITE
Server: kamailio (3.1.5 (i386/linux))
Content-Length: 0
 
 
SIP/2.0 183 Session Progress
CSeq: 14417 INVITE
Via: SIP/2.0/UDP 192.168.1.2:53489;branch=z9hG4bKPj0052793130024dda88418cf7a392b7ae
From: sip:austin@134.121.32.130;tag=8c2e350c064e417c96bda1378470fd46
Call-ID: b637fa62393a45a0a58633c1a8f43a86
To: sip:919731573290@134.121.32.130;tag=09100511163117092280006157
Contact: <sip:134.121.32.130:5060;transport=udp>
Content-Type: application/sdp
Content-Length: 241
Record-Route: <sip:134.33.8.138;lr=on;nat=yes>
 
v=0
o=VoipSwitch 6156 7156 IN IP4 134.33.8.138
s=VoipSIP
i=Audio Session
c=IN IP4 134.33.8.138
t=0 0
m=audio 46976 RTP/AVP 18 96
a=rtpmap:18 G729/8000/1
a=rtpmap:96 telephone-event/8000
a=fmtp:96 0-15
a=sendrecv
a=nortpproxy:yes
 
SIP/2.0 200 OK
CSeq: 14417 INVITE
Via: SIP/2.0/UDP 192.168.1.2:53489;branch=z9hG4bKPj0052793130024dda88418cf7a392b7ae
From: sip:austin@134.121.32.130;tag=8c2e350c064e417c96bda1378470fd46
Call-ID: b637fa62393a45a0a58633c1a8f43a86
To: sip:919731573290@134.121.32.130;tag=09100511163117092280006157
Contact: <sip:134.121.32.130:5060;transport=udp>
Content-Type: application/sdp
Content-Length: 241
Record-Route: <sip:134.33.8.138;lr=on;nat=yes>
 
v=0
o=VoipSwitch 6156 7156 IN IP4 134.33.8.138
s=VoipSIP
i=Audio Session
c=IN IP4 134.33.8.138
t=0 0
m=audio 46976 RTP/AVP 18 96
a=rtpmap:18 G729/8000/1
a=rtpmap:96 telephone-event/8000
a=fmtp:96 0-15
a=sendrecv
a=nortpproxy:yes
 
ACK sip:134.121.32.130:5060;transport=udp SIP/2.0
Via: SIP/2.0/UDP 192.168.1.2:53489;rport;branch=z9hG4bKPj73092b1de9aa4d4498adac484efacfda
Max-Forwards: 70
From: sip:austin@134.121.32.130;tag=8c2e350c064e417c96bda1378470fd46
To: sip:919731573290@134.121.32.130;tag=09100511163117092280006157
Call-ID: b637fa62393a45a0a58633c1a8f43a86
CSeq: 14417 ACK
Route: <sip:134.33.8.138;lr;nat=yes>
Content-Length:  0
 
 
BYE sip:austin@122.178.237.67:13341;ob SIP/2.0
Max-Forwards: 10
CSeq: 1 BYE
Via: SIP/2.0/UDP 134.33.8.138;branch=z9hG4bK029.52d62945.0
Via: SIP/2.0/UDP 134.121.32.130:5060;rport=5060;branch=z9hG4bK091005111656091709252938
From: sip:919731573290@134.121.32.130;tag=09100511163117092280006157
Call-ID: b637fa62393a45a0a58633c1a8f43a86
To: sip:austin@134.121.32.130;tag=8c2e350c064e417c96bda1378470fd46
Content-Length: 0
 
 
SIP/2.0 200 OK
Via: SIP/2.0/UDP 134.33.8.138;received=134.33.8.138;branch=z9hG4bK029.52d62945.0
Via: SIP/2.0/UDP 134.121.32.130:5060;rport=5060;branch=z9hG4bK091005111656091709252938
Call-ID: b637fa62393a45a0a58633c1a8f43a86
From: <sip:919731573290@134.121.32.130>;tag=09100511163117092280006157
To: <sip:austin@134.121.32.130>;tag=8c2e350c064e417c96bda1378470fd46
CSeq: 1 BYE
Content-Length:  0
 


 
On Sun, Oct 9, 2011 at 11:50 AM, Sammy Govind <govoiper@gmail.com> wrote:
Hey,
Can you send in the SIP/SDP invites. I suspect the codecs issue here.
--
Regards,
Sammy


On Sun, Oct 9, 2011 at 8:57 AM, Austin Einter <austin.einter@gmail.com> wrote:
Hi
I am using Kamailio 3.1.5 . I am using RTP proxy also.
I have used default kamailio.cfg.sample fiile , and just added line #!define WITH_NAT.
 
I have another Main proxy. I wanted all my signalling and media packets should just pass through machine where Kamailio and RTP proxy are running.
 
With this I found, call is established, all signalling and media packets are passing through kamailio / rtp-proxy.
So far so good.
 
One way audio stream (from called party to calling party) quality is good.
The other audio stream (from calling party  to called party is very bad.
 
Did anybody face this issue? Please help me to sort out this issue audio quality issue.
 
Regards
Austin
 
 

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