Lab ipc-12 - HSRP Active-Standby

HSRP (Hot Standby Router Protocol) is Cisco's first-hop redundancy protocol. Two routers share a virtual IP address; one is Active, one is Standby. Hosts use the virtual IP as their default gateway. If the Active router dies, the Standby takes over within seconds and hosts never know the difference. This lab configures HSRP between R1 and R2 on the base topology's LAN segment.

What you will learn

• The HSRP architecture: virtual IP, virtual MAC, Active vs Standby state
• HSRP priority and preemption
• HSRPv2 virtual MAC format (0000.0c9f.fXXX where XXX is the 12-bit group number)
• How to read show standby and show standby brief
• Why HSRP groups have names ("HSRP-PROD" not just "HSRP-10")

What this lab does NOT cover

• HSRP versus VRRP (next lab, ipc-13)
• HSRP versus GLBP (lab ipc-14)
• HSRP authentication (similar pattern to OSPF)

Topology

R1 and R2 share the LAN segment 10.20.0.0/24. We configure HSRP group 10 between them, with R1 as Active (priority 110) and R2 as Standby (priority 100).