Cpm Switchover On 7210 Sas-R6 And 7210 Sas-R12 - Nokia 7210 Configuration Manual

System Management
6.2.1.2.2
The Nonstop Routing (NSR) feature on 7210 SAS devices ensures that routing
neighbors are unaware of a routing process fault. If a fault occurs, a reliable and
deterministic activity switch to the inactive control complex occurs; the routing
topology and reachability are not affected, even during routing updates. NSR
achieves HA through parallelization by maintaining up-to-date routing state
information, at all times, on the standby route processor. This is achieved
independent of protocols or protocol extensions and provides a more robust solution
than graceful restart protocols between network routers.
The NSR implementation on the 7210 SAS routers supports all routing protocols. It
allows existing sessions (BGP, LDP, OSPF, and others) to be retained during a CFM
or CPM switchover, including the support for MPLS signaling protocols. No change
is visible to the peers.
Protocol extensions are not required. There are no interoperability issues and
defining protocol extensions for each protocol is not required. Unlike nonstop
forwarding and graceful restart, the forwarding information in NSR is always up to
date, which eliminates possible black holes or forwarding loops.
Traditionally, addressing HA issues has been patched through nonstop forwarding
solutions. The NSR implementation overcomes these limitations by delivering an
intelligent, hitless failover solution. This enables a carrier-class foundation for
transparent networks that is required to support business IP services backed by
stringent SLAs. This level of HA support poses a major issue for conventional routers
whose architectural design limits or prevents them from implementing NSR.
6.2.1.3
During a switchover, system control and routing protocol execution are transferred
from the active to the standby CPM.
An automatic switchover may occur under the following conditions:
A manual switchover may occur under the following conditions:
262
Nonstop Routing on 7210 SAS-R6 and 7210 SAS-R12

CPM Switchover on 7210 SAS-R6 and 7210 SAS-R12

• a fault condition that causes the active CPM to crash or reboot
• the active CPM is declared down (not responding)
• online removal of the active CPM
Use subject to Terms available at: www.nokia.com
7210 SAS-M, T, R6, R12, Mxp, Sx, S Basic System
© 2021 Nokia.
Configuration Guide
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