Nortel Networks 1000ASE-XD, 1000BASE-SX manual Port connection problems, Autonegotiation modes

		Chapter 4 Troubleshooting 177
Table 43 Corrective actions (continued)
Symptom	Probable cause	Corrective action
The Activity LED for a	The switch is experiencing a	See “Port connection problems” next.
connected port is off or	port connection problem.
does not blink (and you	The switch’s link partner is not
have reason to believe
	autonegotiating properly.
that traffic is present).

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.

Using the BayStack 420 10/100/1000 Switch