Active router is 192.168.100.2 priority 100 expires in 9.540 Standby router is local 2 state changes, last state change 23w3d Router A's output reflects that Router A is active with a priority of 100 and may pre- empt. We can also see that the VIP is 192.168.100.1 and that the standby router is 192.168.100.3. With more than two routers participating, it may not be obvious with- out this information which router is the standby router. One important aspect of HSRP that many people miss is that if more than two routers are participating, once active and standby routers have been elected, the remaining routers are neither active nor standby until the standby router becomes active. RFC 2281 states: To minimize network traffic, only the active and the standby routers send periodic HSRP messages once the protocol has completed the election process. If the active router fails, the standby router takes over as the active router. If the standby router fails or becomes the active router, another router is elected as the standby router. HSRP Interface Tracking While HSRP is a wonderful solution that enables recovery from router or Ethernet interface failures, its basic functionality falls short in another area. Figure 13-3 depicts a more complex problem than the one described previously. In this scenario, the serial link connecting Router A to the Internet has failed. Because the router and Ethernet Chapter 13: First Hop Redundancy Internet Router A Router B Ethernet - 192.168.100.0/24 Figure 13-3. Primary Internet link failure without interface tracking interfaces are still up, HSRP is still able to send and receive hello packets, and Router A remains the active router. The network is resilient, SO the packets will still get to the Internet via the F0/1 inter- faces. But why add another hop when we don't need to? If we could somehow influence the HSRP priority based on the status of another interface, we could fail the VIP from Router A over to Router B based on the status of SO/O. HSRP interface tracking allows us to do ex