Pre2 Redundancy And Resiliency; Route Processor Redundancy Plus; Docsis Stateful Switchover; Ubr10-Mc5X20 Line Card Redundancy - Cisco WCM300 - Channel Bonded Cable Modem Implementation Manual

Chapter 2 Cisco Cable Wideband Components

PRE2 Redundancy and Resiliency

The Route Processor Redundancy Plus (RPR+) feature and DOCSIS Stateful Switchover (DSSO) in the
Cisco IOS software provide the Cisco uBR10012 router's PRE2 route processors with fast route
processor failover without DOCSIS line card reboot.

Route Processor Redundancy Plus

The RPR+ feature enables the Cisco uBR10012 router to use two PRE2 route processors in a redundant
configuration: an active and standby PRE2 module. If the active PRE2 module fails, or is removed from
the system, the standby PRE2 detects the failure and initiates a switchover. During a switchover, the
standby PRE2 assumes control of the router, connects with the network interfaces, and activates the local
network management interface and system console.
Using the RPR+ feature, the standby PRE2 module is fully initialized and configured. This allows RPR+
to dramatically shorten the switchover time if the active PRE2 fails, or if a manual switchover is
performed. Because both the startup configuration and running configuration are continually
synchronized from the active to the standby PRE2 route processor, line cards are not reset during a
switchover. The interfaces remain up during this transfer, so neighboring routers do not detect a link flap
(that is, the link does not go down and back up).
The RPR+ feature does not require a full reboot of the system to perform a failover. When the system is
originally initialized, the secondary PRE2 module performs an abbreviated initialization routine—the
module performs all self-checks and loads the Cisco IOS software, but instead of performing normal
systems operations it begins monitoring the primary PRE2 module. If the secondary PRE2 module
detects a failure in the primary module, it can quickly assume the primary responsibility for systems
operations.
During RPR+ switchover, wideband cable modems on the CMTS will stay online. The MAC state for
the wideband cable modem will remain online for a modem registered as a DOCSIS 2.0 modem, or
w-online for a modem registered as a wideband cable modem.

DOCSIS Stateful Switchover

DOCSIS Stateful Switchover increases service uptime by instantaneously switching over between dual
route processors should one processor fail. Switchover takes place without resetting or reloading line
cards or affecting related subsystems or processes. The advantage of DOCSIS Stateful Switchover (with
RPR+) is that a switchover between the primary and standby RP will not require the cable interfaces to
be reset, nor do the modems reregister or go offline. Furthermore, the cable modems retain their
service IDs (SIDs) through the switchover.
For more information on PRE2 and RPR+ and DOCSIS Stateful Switchover, see the document Route
Processor Redundancy Plus on the Cisco uBR10012 Universal Broadband Router.

uBR10-MC5X20 Line Card Redundancy

The Cisco uBR10012 router supports N+1 Redundancy on the cable interface line cards including the
uBR10-MC5X20S/U/H and uBR10-MC5X20U-D line cards, which are used in the Cisco Cable
Wideband Solution.
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Cisco Cable Wideband Solution Design and Implementation Guide, Release 1.0
Wideband CMTS Redundancy and Resiliency
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