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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. 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.
Multicast
A single packet sent to a specific group of endstations on a network.
Port monitoring
The ability to monitor the traffic passing through a port on a device to analyze network characteristics and perform
troubleshooting.
Port speed
The speed that a port on a device uses to communicate with another device or the network.
Port trunking
The ability to combine multiple ports on a device to create a single, high-bandwidth connection.
Protocol
A set of rules for communication between devices on a network.
Quality of Service
A term to describe delay, throughput, bandwidth, and other factors that measure the service quality provided to a
user.
Segment
A section of a LAN that is connected to the rest of the network using a switch, bridge, or repeater.
SNMP
Simple Network Management Protocol. An IETF standard protocol for managing devices on a TCP/IP network.
Spanning Tree
A technique that detects loops in a network and logically blocks the redundant paths, ensuring that only one route
exists between any two LANs.
Spanning Tree Protocol
(STP)
A protocol that finds the most efficient path between segments of a multi-looped, bridged network. STP allows
redundant switches and bridges to be used for network resilience, without the broadcast storms associated with
looping. If a switch or bridge falls, a new path to a redundant switch or bridge is opened.
Switch
A device that interconnects several LANs to form a single logical LAN that comprises of several LAN segments.
Switches are similar to bridges, in that they connect LANs of a different type; however they connect more LANs
than a bridge and are generally more sophisticated.
TCP/IP
Transmission Control Protocol/Internet Protocol. This is the name for two of the most well-known protocols
developed for the interconnection of networks. Originally a UNIX standard, TCP/IP is now supported on almost all
platforms, and is the protocol of the Internet.
TCP relates to the content of the data traveling through a network — ensuring that the information sent
arrives in one piece when it reaches its destination.
IP relates to the address of the endstation to which data is being sent, as well as the address of the
destination network.
Traffic prioritization
Giving time-critical data traffic a higher quality of service over other, non-critical data traffic.
Unicast
A packet sent to a single endstation on a network.
VLAN
Virtual LAN. A logical association that allows users to communicate as if they were physically connected to a single
LAN, independent of the actual physical configuration of the network.
