Hello to all you knowledgeable people!
Our customer has a mixed telephony system with CUCM 4.2, CUCM 6.1 and various h.323 gateways, both acting as transit points to PSTN and IP-PBXs connected as h.323 gateways (Avaya Definity & IP Office boxes). So here's the problem.
When a user on Avaya or PSTN-caller dials a CCM user he is hearing progress tone as would be expected. When CCM users picks up and does blind transfer to another CCM user (same server) the caller hears MOH until the transferrer pushes the 'transfer' button for the 2nd time. After this moment the caller hears silence, no progress tone until the CCM user, to whom the call is transferred picks up. Then normal voice communication occurs. But many callers think something's wrong on not hearing progress tone and hang up. This behaviour is found on both CUCM 4.2 and CUCM 6.1 and on all calls through all gateways (PSTN user via h.323 telephony provider via Cisco IOS gateway to CCM or Avaya user via h.323 to CCM). Avaya PBXs have different gateway settings: some use fast start, some slow start, g.711 anyway.
BUT this behaviour is not observed on calls from CUCM 4.2 to CUCM 6.1 via intercluster trunk.
Is that a bug, a configuration issue or a normal case?
I'm planning to take h225 q931 or asn1 debugs from IOS gateway, but I don't see how it could be related to it, because the problem only occurs on transferred calls and it's not that easy to arrange onsite actions in this case.
Thanks for any suggestions.