Bay Networks NauticaRS Reference Manual page 69

Introduction to Protocols and Routing
Paths are blacklisted if the initial, dialed, call to the path fails to
connect to the remote unit. This does not include a call that has
been answered but dropped due to either a protocol negotiation
failure or a security failure. Each telephone number associated
with the path is called three times in turn, and if all fail to connect,
the path is blacklisted.
Note: Failures on calls for extra bandwidth do not cause a path
to be blacklisted.
Once blacklisted, the path and its routes are, in effect, ignored by
the router for a specified time.
A path is re-dialed when the blacklist timeout parameter (system#
context in BCC and Advanced > System in Nautica Wizard)
expires. The path is re-dialed, meaning each telephone number
for the path is called until either the path comes up or each
number has been called three times. If the call fails the path is
blacklisted once more.
A path also comes off the blacklist table if a call is received along
it from the previously downed router. Also, the blacklist table is
cleared if the router is rebooted.
For information on setting the blacklist timeout parameter, refer
to Chapter 5.
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