Media Anchoring Overview

Media anchoring is the act of processing Session Description Protocol (SDP) transactions. SDP transactions are requests for media resources. These requests must be supervised, and allocation must take into account business, security, and performance requirements.

The basic uses of media anchoring are:

• Hiding the topology of the media network by using NAT.
• Applying bandwidth restrictions and setting the DSCP on processed media packets

The SPDF is the component that applies media anchoring. In new call usage policies you specify whether or not media anchoring is applied. When you specify no-anchoring, media anchoring does not occur for any calls using the policy.

You can release media resources conditionally by using the media-release option. The IMSG can release media resources when handling calls between two entities in the same media realm. When the new call usage policies for both entities specify media release, the IMSG will hand off the media, instructing both parties to communicate media streams directly with one another.