G LOSSARY 167MAC address Media Access Control address; also called hardware or physical address.A layer 2 address associated with a particular network device. Mostdevices that connect to a LAN have a MAC address assigned to themas they are used to identify other devices in a network. MAC addressesare 6 bytes long.main port The port in a resilient link that carries data traffic in normal operatingconditions.MDI Medium Dependent Interface. An Ethernet port connection where thetransmitter of one device is connected to the receiver of anotherdevice.MDI-X Medium Dependent Interface Cross-over. An Ethernet port connectionwhere the internal transmit and receive lines are crossed.MIB Management Information Base. A collection of information about themanagement characteristics and parameters of a networking device.MIBs are used by the Simple Network Management Protocol (SNMP) togather information about the devices on a network. The Switchcontains its own internal MIB.multicast A packet sent to a specific group of endstations on a network.multicast filtering A system that allows a network device to only forward multicast trafficto an endstation if it has registered that it would like to receive thattraffic.NIC Network Interface Card. A circuit board installed in an endstation thatallows it to be connected to a network.port mirroring A system that allows you to copy the traffic from one port on a Switchto another port on the Switch. Port mirroring is used when you wantto monitor the physical characteristics of a LAN segment withoutchanging the characteristics by attaching a monitoring device.port trunks See load sharing.POST Power On Self Test. An internal test that a Switch carries out when it ispowered-up.protocol A set of rules for communication between devices on a network. Therules dictate format, timing, sequencing and error control.
