Understanding Hsrp - Cisco Catalyst 3750-X Software Configuration Manual

Configuring HSRP
This chapter describes how to use Hot Standby Router Protocol (HSRP) on the Catalyst 3750-X
or 3560-X switch to provide routing redundancy for routing IP traffic without being dependent on the
availability of any single router.Unless otherwise noted, the term switch refers to a Catalyst 3750-X
or 3560-X standalone switch and to a Catalyst 3750-X switch stack.
You can also use a version of HSRP in Layer 2 mode to configure a redundant command switch to take
over cluster management if the cluster command switch fails. For more information about clustering, see
Chapter 6, "Clustering Switches"
Cisco.com. If the switch is running the LAN base feature set, only Layer 2 mode is supported.
For complete syntax and usage information for the commands used in this chapter, see these documents:
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This chapter consists of these sections:
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Understanding HSRP

HSRP is Cisco's standard method of providing high network availability by providing first-hop
redundancy for IP hosts onan IEEE 802 LAN conf i gured with a default gateway IP address. HSRP routes
IP traffic without relying on the availability of any single router. It enables a set of router interfaces to
work together to present the appearance of a single virtual router or default gateway to the hosts on a
LAN. When HSRP is configured on a network or segment, it provides a virtual Media Access Control
(MAC) address and an IP address that is shared among a group of configured routers. HSRP allows two
or more HSRP-configured routers to use the MAC address and IP network address of a virtual router.
The virtual router does not exist; it represents the common target for routers that are configured to
provide backup to each other. One of the routers is selected to be the active router and another to be the
standby router, which assumes control of the group MAC address and IP address should the designated
active router fail.
OL-21521-01
Switch command reference for this release
Cisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services, Release 12.2 at
http://www.cisco.com/en/US/docs/ios/12_2/ipaddr/command/reference/fipras_r.html
Hot Standby Router Protocol Version 2 feature module at
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gthsrpv2.html
Understanding HSRP, page 44-1
Configuring HSRP, page 44-5
Displaying HSRP Configurations, page 44-13
C H A P T E R
and see the Getting Started with Cisco Network Assistant, available on
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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