Cabletron Systems SFCS-200WG - Manual (Page 99)

A-3
Troubleshooting
A.1.1 Run Looptest
To determine if an interface is functioning properly, run the looptest utility
on a host that has been disconnected and isolated from the network.
NOTE: Before running looptest, the Receive and
Transmit connectors on the backplate of the
card must be connected to each other using a
short loop of fiber-optic cable. This fiber
should remain on throughout this test.
The looptest utility uses Cabletron Systems’ ATM user-level Application Pro-
gramming Interface. For proper operation, looptest requires read/write
access to the ATM device. To run looptest, enter the following command at
the system prompt in the working directory:
looptest fa0
where fa0 is the default device name for a single ATM adapter.
The looptest utility verifies that the board of an adapter is operating cor-
rectly. Correct operation means that all of the following conditions are true:
1. The self-test has been passed successfully.
2. The firmware has been downloaded successfully.
3. The driver has detected the existence of the hardware.
4. The firmware is running.
5. The physical link is up.
If looptest passes, then the board hardware of the adapter is OK. The next
step is to test the software as shown in Figure A.3.
If looptest fails, the point of failure will be indicated by messages generated
for each of the five items above. Refer to the following subsections for instruc-
tions about testing the individual items.