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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 32 Configuring HSRP
Configuring HSRP
•
The switch supports HSRP MAC address entries in hardware for up to 16 unique HSRP groups.
Because of other switch feature configurations, we recommend that you do not assign more than 64
HSRP interfaces.
•
An HSRP group can use the same HSRP MAC address on a single Layer 3 interface, several Layer 3
interfaces that are all the same multiple of 16, or a consecutive range of 16 Layer 3 interfaces that
are all the same multiple of 16. For more information about HSRP groups, see the
.
•
An interface can belong to multiple HSRP groups, and the same HSRP group can be applied to
different interfaces.
•
If you configure the same HSRP group on multiple VLANs, do not use bridge groups to tie the
multiple interfaces together. Identically-numbered HSRP groups use the same virtual MAC address
and might cause errors if you configure bridge groups.
Enabling HSRP
The standby ip interface configuration command activates HSRP on the configured interface. If an IP
address is specified, that address is used as the designated address for the Hot Standby group. If no IP
address is specified, the address is learned through the standby function. You must configure at least one
routing port on the cable with the designated address. Configuring an IP address always overrides
another designated address currently in use.
When the standby ip command is enabled on an interface and proxy ARP is enabled, if the interface’s
Hot Standby state is active, proxy ARP requests are answered using the Hot Standby group MAC
address. If the interface is in a different state, proxy ARP responses are suppressed.
Note
When multi-VRF CE is configured, you cannot assign the same HSRP standby address to two different
VPNs.
Beginning in privileged EXEC mode, follow these steps to create or enable HSRP on a Layer 3 interface:
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and enter the Layer 3 interface on
which you want to enable HSRP.