[asterisk-users] a=sendonly Music On Hold ignored

[Matthew J. Roth]

Michael,

It looks like your problem is caused by a phone with a non-standard
SDP session version implementation.  The phone is sending an INVITE
with SDP that contains an "a=sendonly" line.  Asterisk should respond
with an OK that contains an "a=recvonly" line, but it responds with
"a=sendrecv" instead.

Asterisk is probably ignoring the SDP in the INVITE, because the phone
never updates the SDP session version.  It remains at 0 throughout the
entire dialog:

 o=  username    sess-id     sess-version  nettype  addrtype  addr
 --  --------    ----------  ------------  -------  --------  -------------
 o=  500         1096000000  0             IN       IP4       192.168.1.109
 o=  500         1096000001  0             IN       IP4       192.168.1.109
 o=  500         1096000000  0             IN       IP4       192.168.1.109

Luckily, there is an option to force Asterisk to ignore the SDP
session version number and treat all SDP data as new data.  Try adding
"ignoresdpversion=yes" to the phone's configuration in sip.conf.

For the sake of future list readers, please respond to this post with
"[RESOLVED]" appended to the subject line if this fixes your problem.

> That's what I get: 
> [root at pbx ~]# asterisk -rx 'module show' | egrep 'format_g729.so|format_pcm.so' 
> format_pcm.so Raw/Sun uLaw/ALaw 8KHz (PCM,PCMA,AU), G. 0 
> format_g729.so Raw G729 data 0 
> 
> What does the 5 (or in my case 0) stand for? 

It's the "Use Count", but I'm not certain how to interpret it.  On one
of my servers chan_sip.so has a use count of 110451 and rising.  That
seems like it should indicate some sort of leak, but Asterisk has been
running continuously for over half a year without any problems.

Regards,

Matthew Roth
InterMedia Marketing Solutions
Software Engineer and Systems Developer