HSRP

Hot Standby Router Protocol

• Cisco proprietary

• An active and standby router is elected.

• There are two versions: version 1 and version 2. Version 2 adds IPv6 support and increases the number of groups that can be configured.

• Multicast IPv4 address:

  • v1 = 224.0.0.2

  • v2 = 224.0.0.102

• Virtual MAC address:

  • v1 = 0000.0c07.acXX (XX = HSRP group number)

  • v2 = 0000.0c9f.fXXX (XXX = HSRP group number)

• In a situation with multiple subnets/VLANs, you can configure a different active router in each subnet/VLAN to load balance.