Cisco Systems 3750E manual Multiple Hsrp, 40-3

Chapter 40 Configuring HSRP and Enhanced Object Tracking

Understanding HSRP

Figure 40-1 Typical HSRP Configuration

Host B

172.20.130.5

	Active	Virtual	Standby
	router	router	router
172.20.128.1		172.20.128.3	172.20.128.2
	Router A		Router B

172.20.128.32	172.20.128.55
Host C	Host A

Multiple HSRP

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The switch supports Multiple HSRP (MHSRP), an extension of HSRP that allows load sharing between two or more HSRP groups. You can configure MHSRP to achieve load-balancing and to use two or more standby groups (and paths) from a host network to a server network. In Figure 40-2, half of the clients are configured for Router A, and half of the clients are configured for Router B. Together, the configuration for Routers A and B establish two HSRP groups. For group 1, Router A is the default active router because it has the assigned highest priority, and Router B is the standby router. For group 2, Router B is the default active router because it has the assigned highest priority, and Router A is the standby router. During normal operation, the two routers share the IP traffic load. When either router becomes unavailable, the other router becomes active and assumes the packet-transfer functions of the router that is unavailable.

See the “Configuring MHSRP” section on page 40-9for the example configuration steps.

Note For MHSRP, you need to enter the standby preempt interface configuration command on the HSRP interfaces so that if a router fails and then comes back up, preemption occurs and restores load sharing

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

OL-9775-02 40-3