Nortel Networks NN43001-121 manual Signaling and Media path between the OC client and CS

Mediation Server 21

•connects clients outside the network to internal Interactive Connectivity Establishment (ICE) components, to enable media traversal of NAT and firewalls

•acts as an intermediary for call flows that a gateway does not support (such as calls from remote workers on an Enterprise Voice client)

The Mediation Server uses the following types of signaling:

•For an inbound call from the CS 1000, the ms-call-source:non-ms-rtc SIP header is inserted by the Mediation Server.

•For an inbound call from the CS 1000, the Mediation Server Back 2 Back User Agent (B2BUA) generates a Session Description Protocol (SDP) offer based on its capabilities in the OCS 2007.

•For an inbound call from the CS 1000, the Mediation Server adds a phone-context attribute to a number that is not in E.164 format.

•For an outbound call from an OC 2007 client, the Mediation Server Back 2 Back (B2B) terminates the dialog and originates a new dialog with the CS 1000. The From header is replaced with a phone number derived from the p-asserted-identity header.

•OC 2007 single step transfer. The Mediation Server terminates the REFER message and returns the response code 202. The Mediation server sends an INVITE message. The Mediation Server does not forward the REFER message to the CS 1000.

Figure 4

Signaling and Media path between the OC client and CS 1000

Nortel Communication Server 1000

Nortel Converged Office Fundamentals — Microsoft Office Communications Server 2007

NN43001-121 01.03 Standard

Release 5.0 30 April 2008

Copyright © 2005–2008, Nortel Networks