Multiplex communications – Fault recovery – Bypass an inoperative switch or inoperative element of a...
Reexamination Certificate
2004-11-24
2010-10-05
Trost, IV, William (Department: 2472)
Multiplex communications
Fault recovery
Bypass an inoperative switch or inoperative element of a...
C370S220000, C726S002000, C726S027000
Reexamination Certificate
active
07808889
ABSTRACT:
A network device includes a primary control unit that establishes a network tunnel with another network device. The network device applies a silent failover technique to failover from the primary control unit to a backup control unit while maintaining the network tunnel. The network tunnel may be, for example, a Layer 2 Tunneling Protocol (L2TP) tunnel, and the network device may be an L2TP Access Concentrator (LAC) or an L2TP Network Server (LNS). The techniques may prevent abnormal termination of the network tunnel during the failover. Once the failover from the primary control unit to the backup control unit is complete, the backup control unit synchronizes sequence numbers associated with the network tunnel with sequence numbers of the non-failed network device, and resolves inconsistencies between subscriber session databases of the backup control unit and the non-failed network device.
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Juniper Networks, Inc.
Shand Roberta A
Shumaker & Sieffert P.A.
Trost, IV William
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