HP Survivable Branch Communication zl Module powered by Microsoft Lync Planning and Design Guide 2011-02

1-16
SBM Overview
SBM Role in a Microsoft UC&C Solution
Figure 1-8. Local PSTN Call
These basic steps occur:
1. The branch user’s Lync client contacts the SBM as its Front-End Server
(registrar). It uses the same SIP port as for other calls:
• TCP 5061 with TLS
• TCP 5060 without TLS
2. The SBM routes and normalizes the call using rules and policies defined
centrally for the branch site, which it retrieves from the CMS. It forwards
the call to the correct Mediation Server.
3. The Mediation Server forwards the call to the correct PSTN gateway. This
gateway acts as a proxy between SIP and the PSTN network, helping the
called party and the calling party to establish the call.