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Route Switch Processor (RSP8) Installation and Configuration Guide
OL-4920-02
Enabling High Availability Features
You can manually synchronize configuration files and ROM monitor environment variables on the active
and the standby RSPs using the following command in privileged EXEC configuration mode:
Caution When you install a second RSP for the first time, you must immediately configure it using the slave
sync config command. This ensures that the new standby RSP is configured consistently with the
active RSP. Failure to do so might result in an unconfigured standby RSP taking control of the router
when the active RSP fails, rendering the network inoperable.
The slave sync config command is also a useful tool for more advanced implementation methods not
discussed in this document. Refer to the Cisco IOS Configuration Fundamentals Configuration Guide
and the Cisco IOS Configuration Fundamentals Command Reference publications, which are available
on the Documentation CD-ROM, online at Cisco.com, or as printed documents.
Enabling High Availability Features
This section discusses the following topics:
• High Availability Feature Overview, page 41
• Hardware and Software Prerequisites, page 43
• Installation Procedures, page 43
• RPR, RPR+, SSO, and FSU Troubleshooting Tips, page 63
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 astandby RSP preloaded with aCisco IOS image in 30seconds to 5 minutes, depending
on the feature. For more information on high service availability (HSA), the system default program,
refer to the “Configuring High System Availability” section on page 25. Like HSA, HA is supported on
the Cisco 7507, Cisco 7507-MX, Cisco 7513, and Cisco 7513-MX routers with two RSP8s, or with one
RSP8 and one RSP16.
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 Feature Overview
HA features include:
• 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.
Command Purpose
Router# slave sync config Manually synchronizes active and standby configuration
files.