Scenario:
- Oracle E-SBC (Acme Packet) with internal media interface and public interface for MS Teams Trunk and media.
- Media Bypass enabled (always) with Local Media Optimisation
- Client is in corporate network (internal), the media traffic should flow beetween client and internal media interface of the SBC (the Client cannot reach public IP-addresses directly, HTTP only via Proxy, E-SBC media interface is reachable from client network)
Problem: Incoming call to MSTeams Client via E-SBC. RTP from caller to callee is fine, but the RTP from the callee to the caller takes 6-7 seconds until it is established.
In the SIP flow you can see, that there is a ReINVITE from E-SBC to MSTreams Cloud, directly after the first 200 OK arrives at the SBC. But the Client/MSTeams SBC needs 6-7 seconds to answer the ReINVITE with the 200 OK. After that, everything is fine, and both can hear each other. But it takes 6-7 seconds until the caller can hear the callee.
Find attached a schematic SIP sequence diagram with the relevant messages and also a Wireshark capture with absolute times
Is that a normal behaviour (it's montioned here, but only for "some cases") or does anybody know how to get around this?
Cheers
Oliver
