In a packet-based telephony network, a media gateway provides information
on active media path connections to an active call server. For instance,
this data may be provided to a backup call server to keep the backup call
server in a warm standby mode. The backup call server polls a media
gateway to retrieve a table of information on active media path
connections. The polling may be done periodically or only during
switchover from the active call server to the backup call server. After
switchover, the backup call server has all necessary details about active
media path connections to provide accurate billing information.
Alternatively, after a temporary failure at the active call server, the
active call server may send a request to the media gateway to retrieve a
table of information on active media path connections.