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CUBE need help with SDP header manipulation

mrvoipstuff
Level 1
Level 1

have setup direct routing recently with CUBE .. My ITSP appears to accept alaw as 1st preference followed only by ulaw as 2nd choice before sending 180 ringing back ... What I noticed is if i call an external number from Jabber registered to on-prem CUCM then it always works as it sends 711alaw as per audio codec preference list ...In Teams phone system I can't specify codec order so I added the below on the SIP-profile on my ITSP facing outgoing dial peer.

request INVITE sdp-header Audio-Media modify "RTP/AVP 0 8" "RTP/AVP 8 0"

this works for the m=audio port# RTP/AVP 0 8 101 19 and changes it to RTP/AVP 8 0 101 19

but the next 2 line remains unchanged which still have PCMU first followed by PCMA as below

a=rtpmap:0 PCMU/8000

a=rtpmap:8 PCMA/8000

.. How can I flip the order so a=rtpmap:8 PCMA/8000 is listed first followed by a=rtpmap:0 PCMU/8000 in next line ??? can't work which SDP-attribute am I modifying to achieve this ??

 

For ref - when calling from Jabber (working) - outgoing invite from CUBE to ITSP is like this

m=audio 44936 RTP/AVP 8 0 101 19

c=IN IP4 x.x.x.x

a=rtpmap:8 PCMA/8000

a=rtpmap:0 PCMU/8000

 

When calling from Teams invite from CUBE to ITSP is like below

m=audio 42494 RTP/AVP 8 0 101 19

c=IN IP4 x.x.x.x

a=rtpmap:0 PCMU/8000   <== this here is what ITSP having problem with. they want the line below (a=rtpmap:8 PCMA/8000) first.

a=rtpmap:8 PCMA/8000

 

appreciate any feedback ...

15 Replies 15

mrvoipstuff
Level 1
Level 1

For reference this is working scenario when calling the same number via Jabber via the same CUBE/ITSP .. I do see that re-invite come in from ITSP but call goes thru ... the difference in outgoing invite of this versus non-working one is that codec order

a=rtpmap:0 PCMU/8000

a=rtpmap:8 PCMA/8000

Which is why I was inclined to think ITSP (or the far-end PABX) cares about the sequence of codec it receives ... full trace attached ... 

CUBE internal call-leg ID: aff7d80-1ef1ff2a-54abc5-4caf530a

CUBE external call-leg ID: E2433423-E05D11EE-95F8A69F-3BB85EF

From: That's My Jabber

Called #: 0746712077