[reSIProcate] SDP Hold question

Tue Nov 21 18:12:51 CST 2006

I have a question about constructing a Hold SDP. I'm using a eyeBeam and
a Grandstream phone.

In the 2 examples below, the first re-Invite, (in magenta) is generated
by pressing the Hold button on an active call on the eyeBeam phone. The
audio becomes muted. Pressing Hold again unmutes the call and audio is
again established. This re-Invite sequence is shuffled through my B2B.

The 2nd re-Invite, (in green) is generated by my B2B on behalf of the
eyeBeam phone (3rd party call control). Audio becomes garbled and I
cannot reconnect the call. Nothing is sent to the eyeBeam phone.

When constructing the Hold SDP in the B2B, all I change is the version
number in the origin line, by using the last received SDP (the manual
un-Hold by the eyeBeam phone) and then incrementing the version value in
the Origin line.

Is there something else I need to do?? Do I need to send the answer (220
OK w/SDP) from the GrandStream phone I receive back to the eyeBeam?

Any thoughts??

INVITE sip:55504 at 135.8.116.96 SIP/2.0
Via: SIP/2.0/UDP
135.8.116.33:5060;branch=z9hG4bK-d87543-e034f66b151da125-1--d87543-;rpor
t
Max-Forwards: 70
Route: <sip:135.8.52.181:5060;lr>
Contact: <sip:55123 at 135.8.116.33:5060>
To: <sip:55504 at avaya.com>;tag=4e7d7140a8da0070
From: "IC 7.1 B2B"<sip:55123 at avaya.com>;tag=00763b3d
Call-ID: 9d476254395d7709ZTU2NTMzOTg2ZDMyYzc4MWNiYjc4MzMzMGUwNGJkYWM.
CSeq: 3 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, NOTIFY
Content-Type: application/sdp
Proxy-Authorization: Digest
username="55123",realm="avaya.com",nonce="MTE2NDE1NzE0NjpTREZTZXJ2ZXJTZW
NyZXRLZXk6Mjc5NTYwOTY2",uri="sip:55504 at 135.8.116.96",response="e3aca7e01
19f70949d78173fc72e446a",algorithm=MD5
User-Agent: AVSipSwitch 1.02b-1
Content-Length: 177

v=0
o=- 17377554 17383243 IN IP4 135.8.116.157
s=eyeBeam
c=IN IP4 135.8.116.157
t=0 0
m=audio 7478 RTP/AVP 0
a=alt:1 1 : 79B29E65 00000006 135.8.116.157 7478
a=sendonly

INVITE sip:55504 at 135.8.116.96 SIP/2.0
Via: SIP/2.0/UDP
135.8.116.33:5060;branch=z9hG4bK-d87543-915302260a54c071-1--d87543-;rpor
t
Max-Forwards: 70
Route: <sip:135.8.52.181:5060;lr>
Contact: <sip:55123 at 135.8.116.33:5060>
To: <sip:55504 at avaya.com>;tag=4e7d7140a8da0070
From: "IC 7.1 B2B"<sip:55123 at avaya.com>;tag=00763b3d
Call-ID: 9d476254395d7709ZTU2NTMzOTg2ZDMyYzc4MWNiYjc4MzMzMGUwNGJkYWM.
CSeq: 5 INVITE
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, NOTIFY
Content-Type: application/sdp
Proxy-Authorization: Digest
username="55123",realm="avaya.com",nonce="MTE2NDE1NzE0NjpTREZTZXJ2ZXJTZW
NyZXRLZXk6Mjc5NTYwOTY2",uri="sip:55504 at 135.8.116.96",response="e3aca7e01
19f70949d78173fc72e446a",algorithm=MD5
User-Agent: AVSipSwitch 1.02b-1
Content-Length: 177

v=0
o=- 17377554 17385540 IN IP4 135.8.116.157
s=eyeBeam
c=IN IP4 135.8.116.157
t=0 0
m=audio 7478 RTP/AVP 0
a=alt:1 1 : 79B29E65 00000006 135.8.116.157 7478
a=sendonly

Bill Kovar
bkovar at avaya.com
Avaya, Inc.
(732) 852-2609

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