PCI FDDI Administrator's Guide

Troubleshooting PCI FDDI
Network Problems
Chapter 3 71
(Dual-ring only)
Adapter can only
communicate with a
subset of hosts on
the local network.
• See “Adapter cannot communicate with
other hosts on the local network.”
• Check for twisted ring (port A cabled to
port A, or B port cable to B port.
• Use fddipciadmin to see if your are
communicating with your upstream and
downstream neighbors on the ring.
Cannot connect to
ring.
• For dual attach stations, check the cables
to verify that the ports are connected to the
appropriate ports in the neighbor stations.
Cannot reach a host
on a remote network
• Use ping to test connectivity to stations on
your local ring.
• Distinguish between an unknown host,
which indicates an /etc/hosts file
problem; and a non-response, which
usually indicates a routing problem.
• Use fddipciadmin to see if you are
communicating with your upstream and
downstream neighbors on the ring.
• Check the arp table with arp -a.
• Use netstat -r to check routing tables.
Refer to the man pages for expected
output.
Ring state is
unstable.
• Use fddipciadmin to check for abnormal
statistics. If attribute LER is near the
Alarm value, check for poor connections.
• Verify opticalpower loss does not exceed 11
decibels between transmitter and receiver
pairs.
Table 3-2 (Continued)
Symptom Action