System information

Troubleshooting AppleTalk
Book Title
9-196
Route flapping
(unstable route)
Turning on debug apple events will not cause apple event-logging to be
maintained in nonvolatile memory. Only turning on apple event-logging
explicitly will store it in nonvolatile memory. Furthermore, if apple
event-logging is already enabled, turning on or off debug apple events will not
affect apple event-logging.
Caution: Because debugging output is assigned high priority in the CPU
process, it can render the system unusable. For this reason, use debug
commands only to troubleshoot specific problems or during troubleshooting
sessions with Cisco technical support staff. Moreover, it is best to use debug
commands during periods of lower network traffic and fewer users. Debugging
during these periods decreases the likelihood that increased debug command
processing overhead will affect system use.
Step 4 If routes are being aged incorrectly, use the appletalk timers global
configuration command to correct the problem. Suggested timer values are 10,
30, and 90 to start, but do not exceed 10, 40, and 120. The first number must
always be 10, and the third value should be three times the second.
You can return the timers to their defaults (10, 20, 60) by using the no
appletalk timers global configuration command.
Timers should be consistently set to the same value throughout the
internetwork, or at a minimum, throughout the backbone of the internetwork.
ZIP storm A ZIP storm occurs when a router propagates a route for which it currently has no
corresponding zone name; the route is then propagated by downstream routers.
Note: Cisco routers provide a firewall against ZIP storms in the internetwork. If a Cisco
router receives a routing update from a neighbor, it does not propagate that new route
until it receives the accompanying zone name.
Possible Problems Solution