Nortel Networks 2500 Series manual Port interface

340Troubleshooting

The Ethernet Routing Switch 2500 Series 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 Ethernet Routing Switch 2500 Series cannot negotiate a compatible mode for correct operation.

•If the autonegotiation feature is not present or not enabled at the connected station, the Ethernet Routing Switch 2500 Series may not be able to determine the correct duplex modes.

In both situations, the Ethernet Routing Switch 2500 Series "autosenses" the speed of the connected station and, by default, reverts to half-duplex mode. If the connected station is operating in full-duplex mode, it cannot communicate with the switch.

To correct this mode mismatch problem, use the following procedure:

1.Use the Port Management page to disable autonegotiation for the suspect port (see "Configuring switch port status" (page 324)).

2.Manually set the Speed/Duplex field to match the speed/duplex mode of the connected station.

You may have to try several settings before you find the correct speed/duplex mode of the connected station.

If the problem persists:

1.Disable the autonegotiation feature at the connected station.

2.Manually set the speed/duplex mode of the connected station to the same speed/duplex mode you have manually set for the Ethernet Routing Switch 2500 Series port.

Port interface

Ensure that the devices are connected using the appropriate crossover or straight-through cable, or that autonegotiation is active.

Nortel Ethernet Routing Switch 2500 Series

Overview — System Configuration

NN47215-500 (323162-B) 02.02 Standard

4.1 19 November 2007

Copyright © 2007, Nortel Networks