The Connection Preserving failover and failback for gateways preserves existing bearer (voice) connections while a branch gateway migrates from one Communication Manager server to another because of network or server failure. However, users on connection-preserved calls cannot use such features as Hold, Conference, or Transfer. In addition to preserving the audio voice paths, Connection Preserving failover and failback extends the time period for recovery operations and functions.

If two parties are on a call that is routed through a branch gateway and the network connection carrying the media signal to the main server is lost, the voice (bearer) channel between the two users remains intact, and the two users can continue talking, unaware that the network connection is down. Even though the two parties can talk to each other, they cannot put the call on hold or conference in another party, those telephony features are not permitted. Avaya’s network recovery strategy includes the Connection Preserving failover and failback feature to ensure that the new server to which the gateway connects retains calls in progress.