Hello Everyone,

Greetings!!!

I was trying to find out some links and or articles that could be helpful in understanding below mentioned call flow in Lync 2013, but wasn't lucky enough.

Can anyone please help me with it

Lync Peer to Peer internal call

Internal Lync client to PSTN Call

Internal Lync client to Remote Lync client

Internal Lync client to Federated user call.

Thanks in Advance.

Best Regards,

I'll assume Media Bypass is enabled and you're using a PSTN gateway.

Basically:

Lync Peer to Peer internal call - as the name suggests, media will flow directly between each end point and signalling via the Front End.

Internal Lync client to PSTN Call - The call with go from the Lync Client --> Front End --> Mediation --> PSTN Gateway --> External. Once established, the mediation server will be taken out of the equation and the media will go direct from the PSTN gateway to the Lync client 

Internal Lync client to Remote Lync client - Same as Peer2Peer, but will go via the Edge server.

Internal Lync client to Federated user call. - Same as above.

This may also help, but it can be a little tough to figure out https://technet.microsoft.com/en-us/library/dn594589(v=ocs.15).aspx