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Chapter 10
Troubleshooting AppleTalk Connectivity
Duplicate or Crossed Network Numbers
It is very easy for an administrator to use the same cable range on two physical
media or to cross address ranges on different media. For example, placing cable
range 5­10 on the Ethernet interface of Router_A and 5­10 on the FDDI inter-
face results in a duplicate network number. It is even more common for an
administrator to accidentally use 5­10 for one network and 7­12 for another.
Because of the overlap, the route table becomes unstable. In troubleshooting, it
is helpful to disable the suspected duplicate interface, and then use the show
appletalk route
command to confirm that the network still exists.
It is possible to simplify administration by using seed routers. A seed
router provides all other routers with the AppleTalk network information
needed to function. Setting the cable range to 0­0 places the router into
AppleTalk discovery mode. One router needs to be configured with a real
cable range and zone per physical media.
Overloaded Network
As with all other protocols, it is possible for AppleTalk to be affected by an
overloaded segment or router. This may be due to other traffic or traffic
within the AppleTalk network itself. It is also possible for the overload to be
a function of ZIP or RTMP traffic within AppleTalk.
Troubleshooting should begin with the show interface command. Note
that this is sans physical or protocol parameters because initially the overload
itself is only being researched. At the initial troubleshooting point, it is not
possible to specify a specific protocol or interface. If an interface (or interfaces)
shows high loads, the administrator should use a protocol analyzer to further
determine the cause. Although debug and show commands may be used as
well, caution must be exercised with the debug command in this situation.
No Resources Listed in Chooser
The Chooser is the Macintosh application that users use to select file and
print services. Frequently, the help desk will receive a report that there are no
resources available--sometimes only reported as an unavailable service.
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