Nortel Networks 1000ASE-XD - Manual (Page 177)

Chapter 4 Troubleshooting 177
Using the BayStack 420 10/100/1000 Switch
Port connection problems
You can usually trace port connection problems to either a poor cable connection
or an improper connection of the port cables at either end of the link. To remedy
these types of problems, make sure that the cable connections are secure and that
the cables connect to the correct ports at both ends of the link.
Port connection problems are also traceable to the autonegotiation mode or the
port interface.
Autonegotiation modes
Port connection problems can occur when a port (or station) is connected to
another port (or station) that is not operating in a compatible mode (for example,
connecting a full-duplex port on one station to a half-duplex port on another
station).
The BayStack 420 Switch negotiates port speeds according to the IEEE 802.3u
autonegotiating standard. The switch adjusts (autonegotiates) its port speed and
duplex mode to match the best service provided by the connected station, up to
100 Mb/s in full-duplex mode as follows:
• If the connected station uses a form of autonegotiation that is not compatible
with the IEEE 802.3u autonegotiating standard, the BayStack 420 Switch
cannot negotiate a compatible mode for correct operation.
• If the autonegotiation feature is not present or not enabled at the connected
station, the BayStack 420 Switch may not be able to determine the correct
duplex modes.
The Activity LED for a
connected port is off or
does not blink (and you
have reason to believe
that traffic is present). The switch is experiencing a
port connection problem. See “Port connection problems ” next.
The switch’s link partner is not
autonegotiating properly.
Table 43 Corrective actions (continued)
Symptom Probable cause Corrective action