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Cabletron Systems Smart 04-0053-01 User Manual

Page 56

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3-12 SmartSwitch ATM User Guide

Managing Parallel PNNI Links

PNNI Routing

However, certain time-sensitive implementations of PNNI may require that link fail occur either immediately or after
a period of time longer than three seconds. Use the

set linkmonitortimeout

command to control the time required

for the SmartSwitch ATM switch to assume a link has failed.

For example, two SmartSwitch ATM switches are connected with parallel PNNI links. To configure the switches to
immediately recognize any lapse in traffic as a downed link, enter the following on both switches:

SmartSwitch # set linkmonitortimeout

TimeoutValue(3) : 0

— Make the timeout instantaneous

SmartSwitch #

If a traffic lapse occurs on one of the links, that link’s port immediately frees up all resource, and all traffic is routed
between the switches through the remaining link.

Notice that the

set linkmonitortimeout

command controls the

TimeoutValue

on a switch-wide basis (not a per-port

basis).

Caution

Remember that while some special uses of PNNI may require the

TimeoutValue

to be zero (0), setting the

TimeoutValue

to less than three seconds may cause

the PNNI network to “bounce,” entering a state of constant (and unnecessary)
reconfiguration. For this reason, care should be taken when setting the

TimeoutValue

to less than three seconds.