object tracking for many protocols other than GLBP. But be careful with it, because though it's very powerful, you can make your router configu- ration SO complicated that someone else will have a hard time figuring out what's going on during an outage. Once we've defined the object, we can reference it with the GLBP weighting parameter: R1 (config-if)# glbp 10 weighting track 2 decrement 10 Now, when object 2 (line-protocol) goes down, the weight will decrement by 10. But that's not all. We can track more than one object. Let's add another, this time pointing to a serial interface: 21(config)#track 3 interface so/o/o line-protocol Now let's add that to the interface's GLBP group: R1 (config-if)# glbp 10 weighting track 3 decrement 10 Here's the configuration of f0/0 SO far: interface FastEtherneto/o ip address 10.0.0.2 255.255.255.0 glbp 10 ip 10.0.0.1 glbp 10 preempt glbp 10 weighting 50 glbp 10 load-balancing weighted Chapter 13: First Hop Redundancy glbp 10 weighting track 2 decrement 10 glbp 10 weighting track 3 decrement 10 And our objects being tracked: track 2 interface FastEtherneto/1 line-protocol track 3 interface Serialo/o/o line-protocol Now, should either f0/1 or s0/0/0 suffer a line-protocol outage, the GLBP gateway will drop its weight by 10. Should they both go offline, the weight will drop by 20. But wait-this is not HSRP, and lowering the weight will only reduce the traffic flow to this router. To make this work the way we want, we need to tell GLBP that if the weight falls below a certain threshold, this router should no longer be used as a forwarder. We do this by adding the lower and upper keywords to the glbp weighting command: R1 (config-if)# glbp 10 weighting 50 lower 35 upper 45 Now, should the weight drop below 35, GLBP will stop using this forwarder. Be careful, though, because as I've configured this, should only one interface come back online, GLBP will not enable this forwarder, since the upper threshold is 45. Let's look at the output from show glbp with one interface up after both