8.2 HSRP Configuration
8.2.7 HSRP over trunk links
The example illustrates the configuration for two HSRP-enabled routers participating in two separate VLANs using InterSwitch Link (ISL). Running HSRP over ISL allows users to configure redundancy between multiple routers that are configured as front ends for VLAN IP subnets. By configuring HSRP over ISLs, users can eliminate situations in which a single point of failure causes traffic interruptions.

To configure HSRP over an ISL link between VLANS, perform the following tasks:

  1. Define the encapsulation format.
  2. Define an IP address.
  3. Enable HSRP.

You enable HSRP using the same steps described in 8.2.1-8.2.5. HSRP is also supported over dot1q trunks and you may trunk over 802.1Q.