38 Installing the PowerConnect DeviceIf the station on the other side of the link attempts to auto-negotiate with a device 10/100/1000BaseTport that is configured to full duplex, the auto-negotiation results in the station attempting to operate inhalf duplex.MDI/MDIXThe device supports auto-detection of straight through and crossed cables on all switching10/100/1000BaseT ports. The feature is part of the Auto-negotiation and is enabled when Auto-negotiationis enabled.When the MDI/MDIX (Media Dependent Interface with Crossover) is enabled, the automaticcorrection of errors in cable selection is possible, making the distinction between a straight throughcable and a crossover cable irrelevant. (The standard wiring for end stations is known as MDI(Media Dependent Interface), and the standard wiring for hubs and switches is known as MDIX.)Flow ControlThe device supports 802.3x Flow Control for ports configured with the Full Duplex mode. By default,this feature is disabled. It can be enabled per port. The flow control mechanism allows the receiving sideto signal to the transmitting side that transmission must temporarily be halted to prevent bufferoverflow.Back PressureThe device supports back pressure for ports configured to half duplex mode. By default, this feature isdisabled. It can be enabled per port. The back pressure mechanism prevents the transmitting side fromtransmitting additional traffic temporarily. The receiving side may occupy a link so it becomesunavailable for additional traffic.Switching Port Default SettingsThe following table gives the port default settings.Table 3-3. Port Default SettingsFunction Default SettingPort speed and mode 10/100/1000BaseT copper: auto-negotiation full duplexPort forwarding state EnabledPort tagging No taggingFlow Control Off (disabled on ingress)Back Pressure Off (disabled on ingress)
