Nortel Networks NN43001-121 - Manual (Page 21)

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
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