Voip Redundancy

Redundancy of both RTP and SIP can be achieved by configuring one NAP per VoIP interface for a specific remote proxy.

Signaling Redundancy

In the above example, we have configured two NAP Network Access Point that reaches the same SIP destination.  In the event the ethernet interface VOIP0 went down, the NAP A would become unavailable, and thus routing would take place using NAP A'.

Media Redundancy

The NAP is also associated to the media by assigning an UDP port range for the RTP.  When NAP is unavailable at the signaling level, the assigned RTP ports aren't being used.  In the above example, if the NAP A then all new outgoing calls would then be using VOIP1 ethernet interface.

Routing

In order for the routing engine to use both NAP A' and NAP A, we need to create one route for each NAP. All routes using unavailable NAP are ignored by the routing engine when routing takes place. NAP availability is a fetaure of Scriptable Routing Engine.