Hot backup routing Protocol (HSRP)
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Hot backup routing protocol
HSRP (Hot Standby Routing Protocol)
Cisco private protocol HSRP group member
Active router
Backup router
Virtual router
Other router HSRP messages
All routers in HSRP send or receive HSRP messages
UDP port number 1985
Use Multicast to send HSRP messages, Multicast address 224.0.0.2
TTL=1HSRP statu
Initial state
Learning state
Monitoring statu
Speaking status
Backup statu
Active HSRP timer
Hello interval (default 3s)
Hold time (default 10s) Hot backup routing protocol HSRP
Cisco Private Protocol Virtual routing redundancy Protocol VRRP
Developed by IETF, RFC 2338
The implementation principle and process are basically the same as those of HSRP.
Different from HSRP in protocol details HSRP port tracking
HSRP priority is reduced when the trace port is not available
Active routers can automatically adjust HSRP preemption according to line conditions: high priority routers regain forwarding rights and become members of active routers configured as HSRP
Switch (config-if) # standby group-number ip virtual-ip-address configure the priority of HSRP
Switch (config-if) # standby group-number priority priority-valueHSRP preemptive configuration
Switch (config-if) # standby group-number preemptHSRP timer configuration configure Hello interval and hold time
Switch (config-if) # standby group-number times hellotime holdtime configure HSRP port tracking
Switch (config-if) # standby group-number track type mod/num interface-priority
View HSRP summary information
Switch#show standby [type mod/num] [group-number] brief
View HSRP details
Switch#show standby
