Information Technology Reference
In-Depth Information
Table9-1
AppleTalk Problem-Prevention Techniques (continued)
Preventive Action
Description
Careful zone mapping can minimize unnecessary NBP
1
traffic.
Planning is particularly important in WANs where traffic
traversing WAN links (such as X.25) can be quite expensive.
In System 6, if a user opens the Chooser, the Macintosh
continually sends NBP BrReq packets. In System 7, a logarithmic
backoff minimizes the amount of traffic generated.
Give all the backbone/WAN connections the same zone name
rather than put them in a zone with a LAN.
In most internetworks, it is not desirable to have the zone names
for all backbone or WAN connections appear in the Chooser list.
If you make the zone name of all the WAN links the same (for
example, ZZSerial), only that entry appears in the Chooser menu.
Design your
network with
attention to the
direction in which
traffic will flow
and minimize the
number of
different zones in
the internetwork
Set AppleTalk
timers to the
default values
throughout the
internetwork
A stable network almost
never
has nondefault timer values
configured. Timers should be consistently set to the
same value
throughout the internetwork, or at a minimum, throughout the
backbone of the internetwork. Check with a qualified technical
support representative before changing AppleTalk default timer
values.
1.
NBP = Name Binding Protocol
Using the test appletalk and ping appletalk Commands
In Cisco IOS Release 11.1 and later, use the
test appletalk
privileged exec
command to help identify
problem nodes. Use the
nbp
(Name Binding Protocol) options of the command to perform informational
lookups of NBP-registered entities. The information returned when using the
nbp
options is useful when
AppleTalk zones are listed in the Chooser but services in those zones are unavailable.
When running the
test appletalk
facility, use the confirm option to check that a name of a specified type
is registered on a device. For example,
nbp confirm 24279.173 my-mac:AFPServer@engineering
confirms
that the name my-mac is registered on the device 24279.173 in the engineering zone. The object type is
AFPServer. The syntax for the
nbp confirm
command is as follows:
nbp confirm
appletalk-address
[
:skt
]
object
:
type
@
zone
The syntax description is as follows:
•
appletalk-address
—AppleTalk network address in the form
network.node
. The argument
network
is the 16-bit network number in the range 1 to 65279. The argument node is the 8-bit node number
in the range 0 to 254. Both numbers are decimal.
•
:skt
—(Optional) Name of socket.
•
object
:
type
—Name of device and the type of service. The colon (:) between object and type is
required.
•
@zone
—Name of the AppleTalk zone where the entity object:type resides.
In software releases prior to Cisco IOS Release 11.0, the
ping appletalk exec
command serves a similar
function. Use this command to verify that a node is reachable from the router (for example,
ping
appletalk 2.24 ping
s AppleTalk node 2.24).
