RightFax to Aastra Mitel MX1 integration aggravation

[gosnells]

I should have posted a query here when this first occurred.
However after a lot of to and fro, our issues are now resolved. This is here for reference to hopefully save someone else weeks of frustration.


Mitel MX1
recent upgrade to v6.3

RightFax server
inbound and outbound stopped working.
Wireshark on the RightFax server (i.e. SIP client to the MX1) showed a 503 Service unavailable error.


Apparently there is a negotiation bug.
MX-One is set with priority codec G711A.

Our fax woes were resolved after the RightFax server was changed to support G711A as the priority codec.
In our case, this was within the Brooktrout Config tool, IP Call Control module, SIP, RTP Parameters.
RTP codec list value was: pcmu pcma Now it is: pcma


Since MX-1 upgrade to version 6.3, codec negotiation does not work properly if the priority order is different at both ends.
Mitel is apparently developing a fix for this codec negotiation issues.


We've had other codec negotiation issues before, way back when our MX1 was at v4. Shame things still just don't gel like they should.