[Opalvoip-user] Call Transfer with Avaya Call Manager

[Dicke J. (ST-CO/ENG2.2) <Jam...@us...>]

I mentioned this in my previous message to the OPAL VOIP User list, and have since gathered some specifics about an issue concerning transfer with Avaya Call Manager.

Call Flow:
1)      Incoming call established.
2)      Transfer initiated. OPAL sends a REFER message.
3)      Avaya Call Manager responds with a 407 Proxy Required.
4)      OPAL sends another REFER, this time with Proxy-Authorization information.
5)      Avaya Call Manager does nothing, and does not respond to the now-authorized REFER message
6)      OPAL retries the refer another 3 times, and then sends BYE.

All relevant OPAL's REFER message fields (i.e. Refer-To, Referred-By) seem to be correct.  All Proxy-Authorization credentials also appear to be correct.

Just out of curiosity, I tested transfer with several non-OPAL software phones, and eventually found one that worked: MicroSIP.  Comparing wireshark traces, I observed the following:
-MicroSIP supports UPDATE messages, while OPAL receives a PRACK prior to the OK to establish the first call
-After sending the authorized REFER message, MicroSIP receives a NOTIFY, which suggests REFER-SUB=true, although I cannot find it explicitly specified.

Since the issue seems is ACM's lack of response, I cannot attribute the failure to anything specific to the OPAL library, especially considering that it transfer works correctly with all other SIP servers we have tested with.  As a result, I'm asking this user list: has anyone experienced this, or similar issue with call transfer? And if so, did you discover any workaround, server setting, or fix?


Best regards,

James Dicke
Bosch Security Systems, Inc.
Communications Systems Division
Design Engineer