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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
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Chapter 36 Configuring HSRP Understanding HSRP
Figure 36-1 Typical HSRP Configuration
HSRP Versions
Cisco IOS Release 12.2(46)SE and later support these Hot Standby Router Protocol (HSRP) versions:
• HSRPv1—Version 1 of the HSRP, the default version of HSRP. It has these features:
–
The HSRP group number can be from 0 to 255.
–
HSRPv1 uses the multicast address 224.0.0.2 to send hello packets, which can conflict with
Cisco Group Management Protocol (CGMP) leave processing. You cannot enable HSRPv1 and
CGMP at the same time; they are mutually exclusive.
• HSRPv2—Version 2 of the HSRP has these features:
–
To match the HSRP group number to the VLAN ID of a subinterface, HSRPv2 can use a group
number from 0 to 4095 and a MAC address from 0000.0C9F.F000 to 0000.0C9F.FFFF.
–
HSRPv2 uses the multicast address 224.0.0.102 to send hello packets. HSRPv2 and CGMP
leave processing are no longer mutually exclusive, and both can be enabled at the same time.
–
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.
Host B
172.20.130.5
172.20.128.32
Host A
172.20.128.55
172.20.128.1 172.20.128.3 172.20.128.2
Virtual
router
Active
router Standby
router
Router A Router B
101361
Host C