Connect Mitel ICP to NORTEL CS1000 with SIP

[hwking]

I have connected a MITEL MCD 5.0 to CS1000 6.0 with SIP. Calls are working in both directions. but I notice that when the CS1000 calls the Mitel, there are two call attempts. The first fails and the second succeeds. With wireshark, I see:

from CS1000: SIP Invite
from Mitel: Status 415 Unsupported Media Type

and the call is rejected. Then the CS1000 tries again:

from CS1000: SIP/SDP Invite
from Mitel: Status 180 Ringing.

and the call completes.

This happens on every call. Normally, this wouldn't be a problem since this all happens in the blink of an eye. but I have two 3300s, a primary and a backup and a route list in the CS1000. I want the CS1000 to route the call to the backup only if the primary is down. However, now what happens, is that when the first call attempt fails, the CS1000 jumps to the next route list entry and sends the SIP/SDP invite. so the backup 3300 is receiving the call. The result is that I can never receive calls at my primary 3300.

I need to have the CS1000 send SIP/SDP on the first attempt. I can find nowhere in the CS1000 where SDP options are programmed. Has anyone seen this. Any suggestions?

Colin

 

[dryaquaman]

I think that's normal call flow for SIP.
The initial invite is to agree and establish what media to use.
For example, I say to you "Do you speak Spanish" and you reply "no".
I then ask "do you speak english" and you reply "yes" and so we then continue our conversation in english. (American English BTW <g>)

For sip it would be "Do you speak G729"? Reply 'no'.
Do "you speak G711" reply yes. Call then establishes in G711.

If your sip trunks are actually down the fail over should work just fine.

Dry Aquaman

http://www.university-music-on-hold.com

 

[LoopyLou]

Si I mean yes.

I'd tell you a UDP joke but I'm afraid you won't get it. TCP jokes are the best because you always get them.