System information

Troubleshooting AppleTalk 9-195
AppleTalk: Network Services Intermittently Unavailable
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
The debug apple events command is useful for solving AppleTalk network
problems because it provides an overall picture of the stability of the network.
In a stable network, the debug apple events command does not return any
information. If, however, the command generates numerous messages, the
messages can indicate where the problems might lie.
Possible Problems Solution