Cisco Catalyst 3560-X Series, Software Configuration Manual

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C H A P T E R
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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Configuring HSRP and VRRP
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 1, “Clustering Switches” and see the Getting Started with Cisco Network Assistant , available on
Cisco.com. If the switch is running the LAN base feature set, only Layer 2 mode is supported.
Cisco IOS Release 12.2(58)SE adds support for the Virtual Router Redundancy Protocol (VRRP) for
IPv4 and IPv6 on switches running the IP base image.
For complete syntax and usage information for the commands used in this chapter, see these documents:
• Switch command reference for this release
•
Cisco IOS IP Command Reference, Volume 1 of 3: Addressing and Services, Release 12.4 :
http://www.cisco.com/en/US/docs/ios/12_2/ipaddr/command/reference/fipras_r.html
• Hot Standby Router Protocol Version 2 feature module:
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gthsrpv2.html
This chapter consists of these sections:
• Understanding HSRP, page 1-1
•
Configuring HSRP, page 1-5
• Displaying HSRP Configurations, page 1-13
•
Configuring VRRP, page 1-13
Understanding HSRP
HSRP is Cisco’s standard method of providing high network availability by providing first-hop
redundancy for IP hosts on an IEEE 802 LAN configured 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