Cabletron Systems Fast Network 10, User Manual

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Chapter 6: FN10 Diagnostics and Troubleshooting
Page 6-4 Fast Network 10 User Guide
6.3.1 Loopback Tests
Built-in local and remote loopback tests can be used to test individual
ports while the FN10 is operational. When in local loopback mode, a port
is disconnected from the network. The FN10 generates loopback packets
for the port, and the port loops the packets back without sending them
onto the network.
During a remote loopback test, the port is in normal operation, sending
and receiving packets to the network. The FN10 generates loopback
packets which are sent to a particular destination device on the port's
network. The destination device echoes the packet back onto the network,
and the originating port receives the packet.
For both types of tests, normal operation is indicated when generated
packets are received back without errors. For remote loopback tests, the
FN10 creates LLC Type 1 test packets for LANs, and Point-to-Point
Protocol (PPP) echo-request packets for managing the out-of-band port.
Both types of loopback tests can be initiated by the NMS. The test results
are reported to the NMS. Refer to the
Fast Network 10 MIB Reference
Guide for information on the MIB variables.
6.4 STATUS AND ACTIVITY INDICATORS
The front panel of the FN10 includes LEDs that indicate the status or
activity of various system components. Figure 6-1 shows the FN10 front
panel LEDs and buttons. The LEDs and buttons are described in Tables
6-1 and 6-2.
NOTE
Loopback testing is automatically performed whenever the
FN10 boots. However, there are no LEDs for the loopback
tests; the results of these tests must be observed by accurate
packet transmission, or read by using an NMS to examine
traps.