System information

Troubleshooting AppleTalk 9-205
AppleTalk Enhanced IGRP: Router Stuck in Active Mode
Enhanced IGRP Active/Passive Modes
An Enhanced IGRP router can be in either Passive or Active mode. A router is said to be passive for
a network when it has an established path to that network in its routing table. The route is in Active
state when a router is undergoing a route recomputation. If there are always feasible successors, a
route never has to go into Active state and avoids a route recomputation.
Possible Problems Solution
Active timer value is
misconfigured
The active timer determines the maximum period of time that an Enhanced IGRP router
will wait for replies to its queries. If the active timer value is set too low, there might not
be enough time for all the neighboring routers to send their replies to the Active router.
Step 1 Check the configuration of each Enhanced IGRP router using the show
running-config privileged exec command. Look for the timers active-time
router configuration command entry associated with the appletalk routing
eigrp global configuration command entry.
Step 2 The value set by the timers active-time command should be consistent among
routers in the same autonomous system. A value of 3 (3 minutes, the default
value) is strongly recommended to allow all Enhanced IGRP neighbors to reply
to queries.
Interface or other
hardware problem
Step 1 If queries and replies are not sent and received properly, the active timer times
out and causes the router to issue an error message. Use the show appletalk
eigrp neighbors exec command and examine the uptime and Q Cnt (queue
count) fields in the output.
The following example is output from the show appletalk eigrp neighbor
command:
Router#show appletalk eigrp neighbor
AT/EIGRP Neighbors for process 1, router id 1
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 200.41 Et0 10 0:00:37 0 3000 0 2
If the uptime counter is continually resetting or if the queue count is consistently
high, there might be a hardware problem. The uptime counter is the elapsed
time, in hours, minutes, and seconds, since the local router first heard from this
neighbor.
Step 2 Determine where the problem is by looking at the output of the
“Stuck-in-Active” error message, which indicates the AppleTalk address of the
problematic node.
Step 3 Make sure the suspect router is still functional. Check the interfaces on the
suspect router. Make sure the interface and line protocol are up and determine
whether the interface is dropping packets.
For more information on troubleshooting hardware, see Chapter 3, “Troubleshooting
Hardware and Booting Problems.”
Flapping route If there is a flapping serial route (caused by heavy traffic load), queries and replies might
not be forwarded reliably. Route flapping caused by heavy traffic on a serial link can
cause queries and replies to be lost, resulting in the active timer timing out.
Take steps to reduce traffic on the link, or increase the bandwidth of the link.
Older version of the
Cisco IOS software
If problems persist, upgrade to the latest release of the Cisco IOS software.