Hsrp Configuration; Hsrp Interface Tracking - Cisco RJ-45-to-AUX Brochure

to the route processor.
Learn state—The route processor transitions to this state and remains in this state until it receives a
hello message from the current active router. The hello message allows the route processor to learn
the virtual IP address of the current virtual router.
Listen state—In this state, the route processor has learned the IP address of the virtual router and is
listening for more updated information through hello messages. In this state, the route processor is
neither active nor standing by. Listen is basically a transitional state from the Learn state to the Speak
state.
Speak state—In this state, the route processor begins to forward its own periodic hello messages and
to notify the other route processors that it is an active participant in the voting process to become an
active or standby route processor. From here, it will forward to either the Active state or the Standby
state.
Standby state—In HSRP, there must be at least one standby route processor. If more than one exists,
the route processors become what are known as standby candidate route processors. The route
processor with the highest standby priority will enter the Active state in the event of a failure.
Active state—The route processor in the Active state acts as the default gateway for the IP address
assigned to the virtual router. It forwards any packets received for the virtual IP address or MAC
address sent from any of the HSRP group's host interfaces. It also continues to send hello messages to
the other route processors to verify that it holds this function.

HSRP Configuration

You can configure more than one HSRP group on a Route Switch Feature Card (RSFC) VLAN interface to
provide a transparent route processor backup per network. Every VLAN interface within an HSRP group
shares a virtual IP and MAC address. By configuring the end users' interfaces to use an HSRP virtual IP
address as a default gateway, no interruption will occur in Layer 3 routing to the end users in the event of a
failure of any route processor.
You can configure HSRP on a number of different types of Cisco route processors, including routers. You can
configure multiple route processors on the same switch with interfaces for the same HSRP group. You can
also configure multiple groups with multiple interfaces on the same route processor.
Note Route Switch Module (RSM), Multilayer Switch Feature Card (MSFC), and RSFC command
sets are virtually identical.
It is important to disable all protocols that enable the host interfaces to discover the real MAC address of an
HSRP standby group route processor interface. When enabling HSRP, ICMP redirects are automatically
disabled. When you use the show running−configuration command under each VLAN interface configured
for HSRP, a line will appear stating no ip redirects. This line indicates that ICMP redirects have been
disabled. To re−enable an HSRP interface, enter Interface Configuration mode and use the command no
standby, followed by the group number.

HSRP Interface Tracking

Interface tracking enables a standby group route processor to automatically adjust the priority levels based on
the availability of the route processor. If a tracked interface becomes unavailable, the HSRP priority of the
route processor is automatically decreased. When a route processor with HSRP tracking fails, it reduces the
likelihood that a route processor with an unavailable interface will remain the active route processor for the
Disabling ICMP Redirects
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