Specifications

A.16 Quick PC Trace Option for Concentrators
A–38 FDDI Configuration Capabilities
A.16 Quick PC Trace Option for Concentrators
A Quick PC Trace option is supported for all DEChub FDDI concentrator modules.
A.16.1 PC Trace Description
As defined by the FDDI standard, PC Trace is a method for recovering from a stuck
beacon condition. All stations that are in the fault domain perform some level of
hardware diagnostic test before attempting to reenter the FDDI network.
Normally, concentrator modules run their full set of hardware diagnostics. This takes
approximately one minute, but gives the highest level of assurance that any hardware
failure would be found.
Quick PC Trace Description
To decrease the recovery time following a trace, the quick PC Trace option has been
added. When this option is enabled, only a subset of the hardware diagnostics is run
whenever a PC Trace occurs. The reduced set of diagnostic tests completes in
approximately 10 seconds. This feature can be enabled and disabled only from the
configuration screen of the module’s setup port.
NOTE
The DECswitch 900EF and the PEswitch 900TX do not have this optional
feature because they normally recover from PC Traces very rapidly (less
than 10 seconds). This is because they are FDDI end stations and have a
much smaller set of FDDI-specific diagnostics to run than an FDDI concen-
trator.