System information

Troubleshooting AppleTalk 9-199
AppleTalk: Interface Fails to Initialize AppleTalk
AppleTalk: Interface Fails to Initialize AppleTalk
Symptom: Router interface connected to a network will not initialize AppleTalk.
Table 9-9 outlines the problems that might cause this symptom and describes solutions to those
problems.
Possible
Problems Solution
Route flapping
(unstable route)
Excessive traffic load on internetworks with many routers can prevent some routers from
sending RTMP updates every 10 seconds as they should. Because routers begin to age out
routes after missing two consecutive RTMP updates, the inconsistent arrival of RTMP updates
can result in constant route changes.
Step 1 Use the show interfaces exec command to check the traffic load. Check the load for
each interface.
The following example is output from the show interfaces command:
Ethernet0 is up, line protocol is up
Hardware is Lance, address is 0000.0c32.49b1 (bia
0000.0c32.49b1)
Internet address is 192.168.52.26/24
MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255,
load 1/255
[...]
The load field displayed in the show interfaces command is the load on the interface
as a fraction of 255 (255/255 is completely saturated), calculated as an exponential
average over five minutes.
Step 2 If the load is less than 50%, reconfiguring timer values might solve the problem by
allowing RTMP updates more time to propagate through the network.
If the load is more than 50%, you might need to segment the network to reduce the
number of routers (and therefore the amount of traffic) on each network segment.
Step 3 Use the debug apple events privileged exec command to determine whether routes
are being aged incorrectly. The output should resemble the following:
Router#debug apple events
AppleTalk Events debugging is on
Router#
%AT-6-PATHNOTIFY: Ethernet0: AppleTalk RTMP path to 250-250
down; reported bad by 200.41
Route flapping
(unstable route)
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.