Recovery feature provides seamless failover and reconstruction of
subscriber session information in the event of a hardware or software
fault within the system preventing a fully connected user session
from being disconnected.
Session recovery is
performed by mirroring key software processes (for example, Session
Manager and AAA Manager) within the system. These mirrored processes remain
in an idle state (in standby-mode), wherein they perform no processing,
until they may be needed in the case of a software failure (for
example, a Session Manager task aborts). The system spawns new instances
of "standby mode" session and AAA Managers for
each active Control Processor (CP) being used.
key system-level software tasks, such as VPN Manager, are performed on
a physically separate packet processing card to ensure that a double
software fault (for example, Session Manager and VPN Manager fails
at same time on same card) cannot occur. The packet processing card
used to host the VPN Manager process is in active mode and is reserved by
the operating system for this sole use when session recovery is
For more information
on Session Recovery, refer to the Session Recovery chapter
in the System Administration
Note that the Inter-Chassis
Session Recovery feature is not supported in this release.