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High Availability Commands for CCNP BCMSN

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This chapter provides information on and commands for Hot Standby Routing Protocol, Virtual Router Redundancy Protocol, and Gateway Load Balancing Protocol.
This chapter is from the book

This chapter is from the book

This chapter provides information and commands concerning the following topics:

  • Hot Standby Routing Protocol (HSRP)
    • —Configuring HSRP
    • —Verifying HSRP
    • —HSRP optimization options
    • —Debugging HSRP
  • Virtual Router Redundancy Protocol (VRRP)
    • —Configuring VRRP
    • —Verifying VRRP
    • —Debugging VRRP
  • Gateway Load Balancing Protocol (GLBP)
    • —Configuring GLBP
    • —Verifying GLBP
    • —Debugging GLBP

Hot Standby Routing Protocol

The Hot Standby Router Protocol (HSRP) provides network redundancy for IP networks, ensuring that user traffic immediately and transparently recovers from first-hop failures in network edge devices or access circuits.

Configuring HSRP

Router(config)#interface fastethernet 0/0

Moves to interface configuration mode

Router(config-if)# ip address 172.16.0.10 255.255.255.0

Assigns IP address and netmask

Router(config-if)# standby 1 ip 172.16.0.1

Activates HSRP group 1 on the interface and creates a virtual IP address of 172.16.0.1 for use in HSRP

Router(config-if)# standby 1 priority 120

Assigns a priority value of 120 to standby group 1

Verifying HSRP

Router# show running-config

Displays what is currently running on the router

Router# show standby

Displays HSRP information

Router# show standby brief

Displays a single-line output summary of each standby group

Router# show standby 1

Displays HSRP group 1 information

Router# show standby fastethernet 0/0

Displays HSRP information for the specified interface

Router# show standby fastethernet 0/0 brief

Displays a summary of HSRP for the specified interface

Router# show standby fastethernet 0/0 1

Displays HSRP group 1 information for the specified interface

HSRP Optimization Options

There are options available that make it possible to optimize HSRP operation in the campus network. The next three sections explain three of these options: standby preempt, message timers, and interface tracking.

Preempt

Router(config)# interface fastethernet 0/0

Moves to interface configuration mode

Router(config-if)# standby 1 preempt

This router will preempt, or take control of, the active router if the local priority is higher than the active router

Router(config-if)# standby 1 preempt delay minimum 180

Causes the local router to postpone taking over as the active router for 180 seconds since that router was last restarted

Router(config-if)# standby 1 preempt delay reload

Allows for preemption to occur only after a router reloads

Router(config-if)# no standby 1 preempt delay reload

Disables the preemption delay, but preemption itself is still enabled. Use the no standby x preempt command to eliminate preemption

HSRP Message Timers

Router(config)# interface fastethernet 0/0

Moves to interface config mode

Router(config-if)# standby 1 timers 5 15

Sets the hello timer to 5 seconds and sets the hold timer to 15 seconds

Router(config-if)# standby 1 timers msec 200 msec 600

Sets the hello timer to 200 milliseconds and sets the hold timer to 600 milliseconds

Interface Tracking

Router(config)# interface fastethernet 0/0

Moves to interface configuration mode

Router(config-if)# standby 1 track serial 0/0 25

HSRP will track the availability of interface serial 0/0. If serial 0/0 goes down, the priority of the router in group 1 will be decremented by 25.

Debugging HSRP

Router# debug standby

Displays all HSRP debugging information, including state changes and transmission/reception of HSRP packets

Router# debug standby errors

Displays HSRP error messages

Router# debug standby events

Displays HSRP event messages

Router# debug standby events terse

Displays all HSRP events except for hellos and advertisements

Router# debug standby events track

Displays all HSRP tracking events

Router# debug standby packets

Displays HSRP packet messages

Router# debug standby terse

Displays all HSRP errors, events, and packets, except for hellos and advertisements

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