Administering Cisco QoS for IP Networks
Tweak and tune your Cisco routers for best performance with this practical guide.
TABLE OF CONTENTS Administering Cisco QoS for IP Networks
Troubleshooting EIGRP
Troubleshooting EIGRP can be a complex process. This due to the fact that while EIGRP remains a hop-by-hop protocol, routing decisions are diffused through neighbors away from the source. This means that tracing a problem that originates in one portion of the network can lead you into other areas of the network that you would not have assumed to be involved at all. This is most commonly seen when troubleshooting SIA routes where a query has propagated away from the originator and never returned. As previously mentioned, 12.1(5a) introduced a mechanism that limits the effects of SIAs.
EIGRP was designed with many built-in show commands that are extremely useful troubleshooting tools. We have already used most of these commands, and we will now see how to use them to conduct step-by-step problem resolution.
Troubleshooting Stuck-in-Active Routes
As stated previously, SIA routes are generated when a query has not been replied to within the active timer period. The important thing to remember about SIAs (and the reason that they re so difficult to troubleshoot) is that an SIA isn t caused by just one problem it s caused by two separate problems. The first is that something caused a route to be unavailable to a router that didn t have a feasible successor for that route. The cause of SIA routes can vary from an incorrect configuration to oversubscribed WAN links. The second problem is that, once that route became active and queries were sent out, something caused a router that received a query...
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