In London, ON last year, we had an Allstream engineer tell us that anything other than DMS-100 protocol was unreliable for passing caller names, as there were known bugs in the NI-2 protocol implemented on Nortel central-office switches that they could not get firmware fixes for. We had to convert the Mitel stuff on our side back to DMS-100 with Allstream, after which outbound caller name display was much more reliable...
Just another data point... A.
