Feature #4582
closedInclude "Call Identifier IE" in AoIP voice channels
100%
Description
TS 48.008 introduced the concept of a "Call Identifier IE" when 3GPP AoIP was added. For some strange reason, it marks this IE as "optional" in the description of the BSSMAP ASSIGNMENT CMD message, but reading through the spec as a whole, it seems like they actually may have wanted to make it conditional on the use of AoIP. It is conditional in HANDOVER REQUEST, INTERNAL HANDOVER COMMAND and some other messages.
The reason is relatively simple: There's also a "RESET IP RESOURCE" procedure (3.1.4.3) which can be triggered by either the BSC or the MSC, and which contains up to 62 Call Identifiers that are to be terminated. How would that procedure every work for calls that had no Call Identifier? This procedure likely is the AoIP successor of the RESET CIRCUIT procedure for classic TDM links.
Given that it's a 32bit integer, we might actually use that same CallID that we already use in the MGCP traffic for the call, allowing correlation of BSSMAP with MGCP based on this identifier.
That part is of course not required, but I would like to see it, if it is possible.
In short, every BSSMAP ASSIGNMENT command for a channel in mode != signalling and which has AoIP (IP transport endpoint) capability should be extended with this IE. Likewise, any HANDOVER REQUEST message for non-signalling AoIP also must include it.
