Nortel Passport 4400 Series Introduction Manual page 32

Passport 4400 Introduction and Road Map
Dedicated Backup
Dial Backup Security
Link and Node Backup
1-24
Allows the Passport 4400 to
establish an alternate
connection via a public
frame backup service or
dedicated leased line.
Data calls are re-
established to the original
destination.
Automatically re-connects
to primary link when service
is re-established.
Uses Calling Line
Identification (CLID) and
CUG on Passport to
authenticate dial-backup
call.
The passport 4400 can
establish a backup link to
either the same or a
different destination. The
Passport network can route
around either link or node
failure.
Passport 4400
Main Link
Failure
ISDN PSTN Dial Backup
Concepts and Applications
Protects against the failure
of the network link.
Alternate connection
automatically made upon
failure of the primary link.
Increases reliability and
availability of branch and
central site solutions.
Provides highest level of
network resilience for
mission critical applications.
Ensures only authorized
Passport 4400 units are
able to dial into network.
Highly resilient and reliable
networking.
ISDN
PSTN
Frame
Relay
Passport 4400