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[edgars at madetowork.pt]

Hi,

I'm having a problem dialing out to a particular customer via a SIP
provider.
When this customer puts the call on hold on his pbx, our asterisk
receives an INVITE with a SDP like this, and also puts the call on hold:

v=0
o=ZTE 415 1 IN IP4 xxx.xxx.xxx.xxx
s=phone-call
c=IN IP4 xxx.xxx.xxx.xxx
t=0 0
m=audio 15030 RTP/AVP 8 101
a=sendonly

We also see on cli an "Started music on hold, class 'default', on
channel 'Local/s at webcare_firstleg-cb00,1'" message.
Then, when he releases the hold, we get a new INVITE with a SDP like
this, but we can't get his audio any more:

v=0
o=root 2842 2843 IN IP4 xxx.xxx.xxx.xxx
s=session
c=IN IP4 xxx.xxx.xxx.xxx
t=0 0
m=audio 18240 RTP/AVP 8 101
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=silenceSupp:off - - - -
a=ptime:20
a=recvonly


Is there any way of blocking this kind of notifications?
We really don't need to get this external "on hold" messages.

I've tried setting "allowexternalinvites=no" on sip.conf, but there's no
difference...

Thanks,
Edgar

[rj2807 at gmail.com]

The latter SDP seems invalid. It has an entirely different o= line
from the previous SDP. Here is a quote from section 8 of RFC 3264 that
describes this rule:

When issuing an offer that modifies the session,
the "o=" line of the new SDP MUST be identical to that in the
previous SDP, except that the version in the origin field MUST
increment by one from the previous SDP.

--
Raj Jain
On Fri, Jun 6, 2008 at 9:57 AM, Edgar Barbosa <edgars at madetowork.pt> wrote: