36 Installing the PowerConnect DeviceMDI/MDIXThe device supports auto-detection of straight through and crossed cables on all switching 10/100/1000BaseTports. The feature is part of the Auto-negotiation and is enabled when Auto-negotiation is enabled.When the MDI/MDIX (Media Dependent Interface with Crossover) is enabled, the automatic correction oferrors in cable selection is possible, making the distinction between a straight through cable and a crossovercable irrelevant. (The standard wiring for end stations is known as MDI (Media Dependent Interface), andthe 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, thisfeature is disabled. It can be enabled per port. The flow control mechanism allows the receiving side tosignal to the transmitting side that transmission must temporarily be halted to prevent buffer overflow.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 becomes unavailablefor 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)
