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Cisco Catalyst Blade Switch 3130 and 3032 for Dell Software Configuration Guide
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Chapter 40 Configuring HSRP
Understanding HSRP
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HSRPv2 has a different packet format than HRSPv1.
A switch running HSRPv1 cannot identify the physical router that sent a hello packet because
the source MAC address of the router is the virtual MAC address.
HSRPv2 has a different packet format than HSRPv1. A HSRPv2 packet uses the
type-length-value (TLV) format and has a 6-byte identifier field with the MAC address of the
physical router that sent the packet.
If an interface running HSRPv1 gets an HSRPv2 packet, the type field is ignored.
HSRPv2 and HSRPv1 are mutually exclusive. HSRPv2 is not interoperable with HSRPv1 on an interface
and the reverse.
Multiple HSRP
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 blade server network to a server network.
, one enclosure with blade servers is configured for Router A, and the other enclosure with
blade servers is configured for Router B. Together, the configuration for Routers A and B establishes 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 40-10
for 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 restores load sharing.