Troubleshooting

The fiber MDAs use only multimode 62.5/125 m fiber cable. The Nortel Networks 100BASE-FX MDA is not supported on single-mode fiber. SC connectors are used on 2-port 100BASE-FX MDAs, and MT-RJ connectors are used on 4-port 100BASE-FX MDAs.

Cables for the GBICs vary depending on the specific GBIC type. For details of the cable requirements for GBICs, refer to Appendix A, “Technical Specifications.”

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 Passport 8100 modules negotiate 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.

The following autonegotiation problems can occur:

If the connected station uses a form of autonegotiation that is not compatible with the IEEE 802.3u autonegotiating standard, the Passport 8100 module cannot negotiate a compatible mode for correct operation.

If the autonegotiation feature is not present or is not enabled at the connected station, the Passport 8100 module may not be able to determine the correct duplex mode.

In both situations, the Passport 8100 module 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.

204515-C

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Nortel Networks 1000BASE-XD, 8100 manual Autonegotiation Modes