[Asterisk-Users] Codec order sent wrong from Asterisk

Álvaro Palma apalma at opschile.cl
Thu Feb 23 08:01:53 MST 2006


I'm communicating a softphone (SJPhone) to a Grandstream phone GXP-2000.
The codec order on each one is the next:

SJPhone: GSM - iLBC - PCMA - PCMU
GXP2000: G729 - GSM - PCMA - PCMU

(I have a G729 license, so there's no problem with transcoding G729)

In my sip.conf, I've defined the following codec order:

disallow=all
allow=g729
allow=gsm
allow=g726
allow=alaw
allow=ulaw

And my peers shows this order correctly:

Codecs       : 0x11e (gsm|ulaw|alaw|g726|g729)
Codec Order  : (g729,gsm,g726,alaw,ulaw)

Canreinvite is set to NO.

But, if I initiate a call from the softphone to GXP-2000, Asterisk
always to the GXP phone GSM as the first codec choice, instead of G729,
as I could check with ethereal running in the same server than Asterisk.
The SIP INVITE from Asterisk to GXP looks like

*****************************************************************
Request-Line: INVITE sip:5805907 at 192.168.1.105;user=phone SIP/2.0
Message Header
Message body
     Session Description Protocol
         Session Description Protocol Version (v): 0
         Owner/Creator, Session Id (o): root 27682 27682 IN IP4 192.168.1.2
         Session Name (s): session
         Connection Information (c): IN IP4 192.168.1.2
         Time Description, active time (t): 0 0
         Media Description, name and address (m): audio 14224 RTP/AVP 3 
18 111 8 0
             Media Type: audio
             Media Port: 14224
             Media Proto: RTP/AVP
             Media Format: GSM 06.10
             Media Format: ITU-T G.729
             Media Format: 111
             Media Format: ITU-T G.711 PCMA
             Media Format: ITU-T G.711 PCMU
         Media Attribute (a): rtpmap:3 GSM/8000
             Media Attribute Fieldname: rtpmap
             Media Attribute Value: 3 GSM/8000
         Media Attribute (a): rtpmap:18 G729/8000
             Media Attribute Fieldname: rtpmap
             Media Attribute Value: 18 G729/8000
         Media Attribute (a): fmtp:18 annexb=no
             Media Attribute Fieldname: fmtp
             Media Attribute Value: 18 annexb=no
         Media Attribute (a): rtpmap:111 G726-32/8000
             Media Attribute Fieldname: rtpmap
             Media Attribute Value: 111 G726-32/8000
         Media Attribute (a): rtpmap:8 PCMA/8000
             Media Attribute Fieldname: rtpmap
             Media Attribute Value: 8 PCMA/8000
         Media Attribute (a): rtpmap:0 PCMU/8000
             Media Attribute Fieldname: rtpmap
             Media Attribute Value: 0 PCMU/8000
         Media Attribute (a): silenceSupp:off - - - -
             Media Attribute Fieldname: silenceSupp
             Media Attribute Value: off - - - -
*****************************************************************

So it can be clearly seen how GSM is before G729.

Anybody knows if this is an existing bug? Or am I doing something wrong?
Thanks a lot for your attention.

-- 
Atly.
Alvaro Palma



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