Cisco ASR 5000 Series, Обзор продукта

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Enhanced Charging Service Overview
Redundancy Support in ECS ▀
Cisco ASR 5000 Series Product Overview ▄
OL-22938-02
Redundancy Support in ECS
This section describes the redundancy support available in ECS to recover user sessions and charging records in the
event of software/hardware failure.
Caution:
Persistent data flows are NOT recoverable during session recovery.
Important:
Redundancy is not available in the current version of the Cisco XT2 platform.
Intra-chassis Session Recovery Interoperability
Intra-chassis session recovery is coupled with SessMgr recovery procedures.
Intra-chassis session recovery support is achieved by mirroring the SessMgr and AAAMgr processes. The SessMgrs are
paired one-to-one with the AAAMgrs. The SessMgr sends checkpointed session information to the AAAMgr. ECS
recovery is accomplished using this checkpointed information.
Important:
In order for session recovery to work there should be at least four packet processing cards, one
standby and three active. Per active CPU with active SessMgrs, there is one standby SessMgr, and on the standby CPU,
the same number of standby SessMgrs as the active SessMgrs in the active CPU.
There are two modes of session recovery, one from task failure and another on failure of CPU or packet processing card.
Recovery from Task Failure
When a SessMgr failure occurs, recovery is performed using the mirrored ―standby-mode‖ SessMgr task running on the
active packet processing card. The ―standby-mode‖ task is renamed, made active, and is then populated using
checkpointed session information from the AAAMgr task. A new ―standby-mode‖ SessMgr is created.
Recovery from CPU or Packet Processing Card Failure
When a PSC, PSC2, or PPC hardware failure occurs, or when a planned packet processing card migration fails, the
standby packet processing card is made active and the ―standby-mode‖ SessMgr and AAAMgr tasks on the newly
activated packet processing card perform session recovery.