54GLOSSARY
loop | An event that occurs when two network devices are connected by |
| more than one path, thereby causing packets to repeatedly cycle |
| around the network and not reach their destination. |
MAC | Media Access Control. A protocol specified by the IEEE for determining |
| which devices have access to a network at any one time. |
MAC address | Media Access Control address; also called hardware or physical address. |
| A layer 2 address associated with a particular network device. Most |
| devices that connect to a LAN have a MAC address assigned to them |
| as they are used to identify other devices in a network. MAC addresses |
| are 6 bytes long. |
MDI | Medium Dependent Interface. An Ethernet port connection where the |
| transmitter of one device is connected to the receiver of another |
| device. |
| Medium Dependent Interface |
| where the internal transmit and receive lines are crossed. |
multicast | A packet sent to a specific group of endstations on a network. |
NIC | Network Interface Card. A circuit board installed in an endstation that |
| allows it to be connected to a network. |
POST | Power On Self Test. An internal test that a Switch carries out when it is |
| |
protocol | A set of rules for communication between devices on a network. The |
| rules dictate format, timing, sequencing and error control. |
repeater | A simple device that regenerates LAN traffic so that the transmission |
| distance of that signal can be extended. Repeaters are used to connect |
| two LANs of the same network type. |
router | A device that provides WAN links between geographically separate |
| networks. |
RPS | Redundant Power System. A device that provides a backup source of |
| power when connected to a Switch. |
segment | A section of a LAN that is connected to the rest of the network using a |
| switch or bridge. |