Introduction

The Fail-over process is using a list of servers with different priorities and preferences for load balancing and fail-over redundancy. This list is provided by the DNS server.

The decision of a first and maybe a second and maybe a third … transport destination is taken per any dialog creating client transaction ( REQUEST ) independently. There might be multiple server in use by one account for different dialogs.
Our rule is:

• New dialog creating INVITEs (under control) of the user start with the last server.
• Non-INIVTE dialog creating Requests (not having a user waiting for the result) start with the highest priority server, so trying a failback.
• Once Failover/Failback was successful, the REGISTRATION process are informed to join that server.

Provisioning Parameter

Via Auto-provisioning, the Fail over timer of 32 Seconds can be changed to a lower value.