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.

MDI-X

Medium Dependent Interface Cross-over. An Ethernet port connection

 

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

 

powered-up.

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.

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3Com 3C16987A manual Loop, Multicast, Protocol, Repeater, Router, Segment