User's Manual

20 Overview

Nortel Networks Confidential

The RTP Media Portal handles Network Hiding for the media stream.

For information on the RTP Media Portal, refer to the MCP RTP Media

Portal Basics document.

Note: The SIP Application Module cannot map SDP information

without an RTP Media Portal. It only performs address mapping for

SIP header fields. Therefore, SDP passes through untouched. If the

server must map SDP address information, then you need an RTP

Media Portal.

The SIP Application Module is configured to use an RTP Media Portal

to originate and terminate media streams (RTP/RTCP). The

SIP Application Module uses extended Media Gateway Control

Protocol (MGCP+) to allocate and release resources on the RTP Media

Portal for each session as needed.

Enterprise Clients

The SIP Application software uses the RTP Media Portal to hide

sensitive IP address information about SIP clients behind a firewall in

an Enterprise network. The exception to this occurs when the originator

and terminator of the request are both part of the same network. This

status is determined by checking the domains in the From header and

Request-URI of the SIP Invites. If both SIP clients belong to the same

Enterprise network, the SIP Application Module does not use the RTP

Media Portal. Administrators can override this behavior by provisioning

the AlwaysUseMediaPortal domain parameter in the Provisioning

Client (for more information about this parameter, see the SIP

Provisioning Client User Guide). See Figure 6, “RTP Media Portal

interworking with Enterprise or foreign clients.”