call path Verizon -> Avaya SBCE > SM > CM
Receiving a mixture of the following in SIP trace's on CM, ASM and SBCE for the reported dropped calls:
600 Busy everywhere
403 Forbidden
----BYE---> incoming call was disconnected in mid conversation after 1 min. (Message was coming from Vendor due to NOTIFY for DTMF coming from SBCE see below for further information)
14:02:02.004 |--Bad Eve->| (8) 489 Bad Event (Event type is not supported)
14:02:02.123 |<--NOTIFY--| (8) Ev:telephone-event;rate=1000
By checking cfg of SBCE, one severe problem found SIP trunk environment, user set max sessions per endpoint to be 5 only.
It means that it can only allow 5 calls to this trunk which is causing SBC reject so many calls with 403 Forbidden. user set max sessions per endpoint would match user’s license.
NOTIFY msgs being sent due to DTMF which were also dropping calls. The service provider did not accept NOTIFY for DTMF, but in cfg, user set it as: Sip Notify
Setting the DTMF Support to ‘none’ will prevent the SBC to not mess around with the DTMF, and will pass the inband DTMF signal to the SP. The SP should enable to handle it automatically.
