High Availability Features - Cisco RSP2 - Route Switch Processor 2 Installation And Configuration Manual

High availability (HA), an alternative to the default high system availability (HSA) feature, is a series
of features that minimizes system downtime through a "warm standby." Warm standby allows the system
to switch over to a standby RSP preloaded with a Cisco IOS image in 30 seconds to 5 minutes, depending
on the feature. For more information on high service availability (HSA), the system default program,
refer to the
the Cisco 7507 and the Cisco 7513 routers with two RSP2s, or with one RSP2 and one RSP4/4+.
A router configured for HA has two RSPs, an active RSP and a standby RSP. The active RSP controls
all functions of the router, and the standby RSP monitors the active for failure.

High Availability Features

HA features include:
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OL-4923-01 B0
"Configuring High System Availability" section on page
Single Line Card Reload (SLCR)—Speeds recovery of a failed router by reloading a failed line card
without reloading other line cards on the network backplane. SLCR isolates the fault to a single
Versatile Interface Processor (VIP2 or VIP4) or Legacy interface processor card, and accelerates
recovery time by reloading only the faulty VIP or Legacy interface processor card. Physical lines
and routing protocols on the other line cards of the network backplane remain active. The system
continues forwarding packets with minimal interruptions.
SLCR is disabled by default and needs to be manually configured. When SLCR is enabled, and more
than two linecards crash simultaneously, all line cards will be reset.
For more information on how to configure SLCR, refer to the Cisco 7500 Single Line Card Reload
feature module at
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120s/120s13
/slcr.htm.
Route Processor Redundancy (RPR)—Speeds recovery of a failed router by accelerating switchover
to the standby RSP. The standby RSP is preinitialized with the same full Cisco IOS software image
as on the active RSP. When the active RSP fails, the standby RSP takes over. The line cards are OIR
inserted by the standby RSP during the switchover. Switchover time is reduced to 4 to 5 minutes
with RPR.
RPR is disabled by default, and needs to be manually configured. For more information on RPR,
refer to the Route Processor Redundancy and Fast Software Upgrade on Cisco 7500 Series Routers
feature module available online at
http://www.cisco.com/univercd/cc/td/doc/product/software/ios120/120newft/120limit/120st/120st
16/st_rpr7x.htm.
Route Processor Redundancy Plus (RPR+)—Like RPR, RPR+ speeds recovery of a failed router by
accelerating switchover to the standby RSP. The RPR+ feature, an enhancement of RPR, prevents a
VIP from being reset and reloaded when a switchover occurs between the active and standby RSPs.
Because VIPs are not reset and microcode is not reloaded on the VIPs, and the time needed to parse
the configuration is eliminated, switchover time is reduced to 30 to 40 seconds.
Online removal of the active RSP causes all line cards to reset and reload, which is equivalent to an
RPR switchover, and results in a longer switchover time. When it is necessary to remove the active
RSP from the system, first issue a switchover command to switch from the Active RSP to the
Standby RSP.
RPR+ is disabled by default, and needs to be manually configured. RPR+ does not support the
Legacy interface processor card. The system will default to RPR if the router includes an Legacy
interface processor card. For more information on how to configure RPR+, refer to the RPR+ on
23. Like HSA, HA is supported on
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