80 C HAPTER 5: ETHERNETAutonegotiation This feature enables some ports to identify and negotiate speed andduplex mode with a remote device.ImportantConsiderationsn You can use this command to configure the same setting on multipleports simultaneously. When you specify multiple port numbers, thesystem prompts you to choose the setting and then applies it to all ofthe ports.n In most cases, if autonegotiation does not properly detect the remoteport speed, the vendor of the remote device implemented eitherautonegotiation or a change in port speed in a noncompliant way. Ifautonegotiation does not properly detect the port speed, you canmanually set the port speed and duplex mode.n Table 6 lists Ethernet port types on your system, whether they supportautonegotiation, and which features they negotiate.Table 6 Port Types and Autonegotiation AttributesPort TypeSupportsAutonegotiation?NegotiableAttributesDefault Valuesfor NegotiableAttributes10/100BASE-TX Yes Port speedDuplex mode10 MbpsHalf-duplex100BASE-FX No Not applicable Not applicable1000BASE-SX Yes Duplex modeFlow controlFull-duplexIf autonegotiationis enabled, thesystem’s besteffort is On1000BASE-LX GBIC Yes Duplex mode*Flow control* LX GBIC, and SX GBIC duplex modes are fixed at full-duplex at this release.Full-duplex*If autonegotiationis enabled, thesystem’s besteffort is On1000BASE-SX GBIC Yes Duplex mode*Flow controlFull-duplex*If autonegotiationis enabled, thesystem’s besteffort is On
