Summary
229
Other commands such as show ip eigrp traffic can be used to see if
updates are being sent. If the counters for EIGRP input and output packets
don't increase, no EIGRP information is being sent between peers.
The show ip eigrp events command is an undocumented command.
This command displays a log of every EIGRP event--when routes are
injected and removed from the routing table, and when EIGRP adjacencies
reset or fail. This information can be used to see if there are routing instabil-
ities in the network.
All of these commands are intended to be used at the discretion of the sys-
tem administrator when troubleshooting a problem in the network. The
information provided by these commands can be used for many more issues
than have been discussed in this section.
Summary
T
his chapter has been fairly extensive. Just to refresh your memory, we
discussed the differences between and limitations of distance-vector and
link-state routing protocols. Link-state routing protocols or a hybrid of link-
state routing and distance-vector protocols provide for greater scalability
and stability.
EIGRP, which was the main focus of the chapter, is a hybrid of link-state
routing and distance-vector protocols. It provides greater stability than
IGRP, which was also discussed, and allows for equal-cost load balancing,
controlled routing updates, and formal neighbor adjacencies.
We also looked at how to configure, tune, and troubleshoot EIGRP, how
to load balance, and how to redistribute routes using EIGRP.
So far in this book we have covered OSPF, a touch of RIP, IGRP, and
EIGRP. So what's left? The Border Gateway Protocol and its components.
This protocol is so complex that it will be covered in not one, not two, but
the next three chapters.
Key Terms
Before taking the exam, make sure you're familiar with the following terms:
active route
Autonomous System Boundary Router (ASBR)
Enhanced IGRP (EIGRP)
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