Information Technology Reference
In-Depth Information
AppleTalk Configuration Mismatches
A configuration mismatch occurs if all the AppleTalk routers on a given cable do not agree on the
configuration of that cable. This means that all routers must have matching network numbers, a matching
default zone, and a matching zone list.
To protect against configuration errors that violate this rule, Cisco AppleTalk routers block activation of
any port on which a violation of this rule exists. At interface initialization, if other routers on the network
do not agree with the way a router is configured, the router does not allow AppleTalk to become
operational on that interface. Cisco routers attempt to restart such an interface every two minutes to
avoid outages that result from transient conditions.
However, if the router is already operational and another router whose configuration does not match
becomes active, the router continues to operate on that interface until the interface is reset. At that point,
the interface fails to become active. When the show appletalk interface exec command is issued, the
router indicates a port configuration mismatch.
The following is sample output from the show appletalk interface command when a configuration
mismatch exists:
Ethernet 0 is up, line protocol is up
AppleTalk routing disabled, Port configuration mismatch
AppleTalk cable range is 4-5
AppleTalk address is 4.252, Valid
AppleTalk zone is “Maison Vauquer”
AppleTalk port configuration conflicts with 4.156
AppleTalk discarded 8 packets due to input errors
AppleTalk discarded 2 packets due to output errors
AppleTalk route cache is disabled, port initializing
Line 2 of the command output shows that routing has been disabled due to a port configuration
mismatch. Line 6 indicates the AppleTalk address of the conflicting router.
You can also display the NBP registered name of the conflicting router, which can simplify resolution of
a port mismatch problem. To see registered NBP names, enable the appletalk name-lookup-interval
global configuration command. This causes the show appletalk interface exec command output to
display nodes by NBP registration name.
Phase 1 and Phase 2 Rule Violations
When Phase 1 and Phase 2 routers are connected to the same internetwork, the internetwork
specifications must conform to two rules:
There can be no wide cable range specifications in the Phase 2 extended portion of the internetwork.
That is, no cable ranges can span more than a single (unary) network number. For example, the cable
ranges 2-2, 9-9, and 20-20 are all acceptable. The cable ranges 10-12 and 100-104 are not
acceptable.
Multiple zones cannot be assigned to unary cable ranges.
If these rules are not followed, connectivity between the nonextended and extended portions of an
internetwork becomes degraded and might be lost. In particular, services located on nonextended
networks using Phase 1 routers will not be visible on the other side of the Phase 1 router.
Search WWH ::




Custom Search