User guide

Chapter 5: Phone Book Configuration
Multi-Tech Systems, Inc. MVPGSM 82
Local Survivability
In cases where the connectivity to the network is not available (no response received from the IP
Address/URL set in Local Survivability – Link Monitor Details), Local Survivability can route calls strictly
through the available entries found in the Inbound and Outbound Phone Books. IP Survivability utilizes the
Outbound Phone Book for call routing while Internal Survivability uses the Inbound Phone Book.
IP Survivability Example: You have an MVPGSM with Channel 1 using SIP extension 301 and Channel 2 using
SIP extension 302. A GSM call is received on Channel 1 and is intended for a remote office (809) represented
by the black arrows. Unfortunately, the survivability destination on the Internet is not responding, so Local
Survivability mode is processed, represented by the red arrows. With the survivability link monitor reporting
no connectivity, IP Survivability routes the call to the IP Phone at extension 356 as this is the route set for
survivability. There needs to be an Outbound Phone Book entry associated with this.