10BASE-T: The specification for running Ethernet on UTP. This stands for 10 Mbps, baseband signaling (the signaling method used by Ethernet networks), over twisted pair cable.

10BASE-5: An Ethernet specifications, which uses a thick coaxial cable. 10BASE-5 is seldom installed in new Ethernet networks today.

10BASE-2: An Ethernet specification that uses a thin coaxial cable medium. 10BASE-2 is only used in very small office networks.

Asynchronous Transfer Mode (ATM): A type of switching technology in which the switches are small, fixed-length cells containing data.

Backbone: A segment of network that links several individual workgroup or department LANs together in a single building. It is also used to link several building LANs together in a campus environment.

Bridges: Bridges filter packets between LANs by making a simple forward/don't forward decision on each packet they receive from any of the networks to which they are connected.

Cache: Is fast ram that the processor uses to speed up its processing.

Carrier Sense Multiple Access with Collision Detection (CSMA/CD): An element defined by the 802.3 specifications. It is an access method, which is used by stations connected to an Ethernet LAN. In this method each station contends for access to the shared medium.

CD-ROM: Is a drive that is used for installing additional software from a CD or compact disk much like the one that is used for music. The CD-ROM will also play music CDs.

Collision: When two stations try to send packets at the same time. In Ethernet networks, collisions are considered normal events and the CSMA/CD access method is designed to quickly restore the network to normal activity after a collision occurs.

Ethernet: The most popular LAN technology in use today.

Fiber Distributed Data Interface (FDDI): LAN technology that runs at 100 Mbps, a much higher data rate than Ethernet or Token Ring. Originally FDDI networks required fiber optic cable, but today they can be run on UTP as well.

Floppy Drive and Floppy Disks: Can be used to store and transport documents and email very small programs between two systems.

Gig or Gigabytes (Gb): A gig is also a measure of storage capacity typically associated with hard drives. A gig is approximately a billion characters or bytes of data. One letter can be stored in one byte.

Hard Drive: The hard drive is where your programs and documents are saved. The hard drive is for long-term storage and holds it's information even when the computer is off.

IEEE 802.3: An Ethernet specification commonly defined by the Institute of Electrical and Electronic Engineers (IEEE). The 802.3 specification covers rules for configuring Ethernet LANs, the types of media that can be used, and how the elements of the network should interact.

Intelligent Hubs: Intelligent hubs are wiring concentrators, which can be monitored and managed by network operators.

LAN Internetwork: Connecting disparate and geographically dispersed local area networks together to form an enterprise system.

Local Area Network (LAN): A LAN is a high-speed communications system designed to link computers and other data processing devices together within a small geographic area such as a workgroup, department, or a single floor of a multi-story building.

Manageable Hubs: Another definition for intelligent hubs. Each of the ports on the managed hub can be configured, monitored, and enabled or disabled by a network operator from a hub management console.

Meg or Megabyte (Mb): A meg is a measure of storage capacity typically associated with ram, approximately one million Bytes or characters of data or program space. Imagine each letter of a book taking up one byte.

Modems: A modem allows a computer to communicate over the phone lines to Internet service providers, fax machines and bulletin board services.

Modular Hubs: A modular hub starts with a chassis, or card cage, with multiple card slots, each of which can accept a communications card, or module. Each module acts like a stand-alone hub; when the communications modules are placed in the card slots in the chassis, they connect to a high-speed communications backplane that links them together so that a station connected to a port on one module can easily communicate with a station on another module.

Network Interface Card (NIC): The physical connection from the computer to the network is made by putting a network interface card (NIC) inside the computer and connecting it to the shared cable.

Open Systems Interconnect Reference Model (OSI): A communications model developed by the International Standards Organization (ISO) to define all of the services a LAN should provide. This model defines seven layers, each of which provides a subset of all of the LAN services. This layered approach allows small groups of related services to be implemented in a modular fashion that makes designing network software much more flexible.

Packet: In a shared media network, when one station wishes to send a message to another station it uses the network software to put the message in an envelope. This envelope is called a packet.

Processor or CPU (Central Processing Unit): The heart of the computer is the CPU. It carries out the instructions that it pulls from RAM.

RAM (Random Access Memory): Is memory where loaded programs and data reside. This memory is empty when the system is off. Most software manufacturers will tell you how much memory their programs require when running and much hard drive space they take up.

Routers: Routers are more complex internetworking devices and are also typically more expensive than bridges. They use Network Layer Protocol Information within each packet to route it from one LAN to another.

Shared Media: Shared media technology means that all of the devices attached to the LAN share a single communications medium, usually a coaxial, twisted pair or fiber optic cable.

Shielded twisted pair (STP): Cable that comes with a shielding around the cable to provide more protection against electromagnetic inter-ference (EMI).

Software: Anything that occurs on the computer is done by lists of instructions called software.

Stackable Hubs: Stackable hubs look and act like stand-alone hubs except that several of them can be "stacked" or connected together, usually by short lengths of cable. When they are linked, they act like a modular hub in that they can be managed as a single unit.

Stand-alone Hubs: Single box-level products with a number of ports. Stand-alone hubs usually include some method of linking them to other stand-alone hubs - either by connecting them together with a length of 10BASE-5 coaxial cable or cascading them using twisted pair between individual ports on each hub.

Token Ring: A major LAN technology in use today. Token Ring rules are defined in the IEEE 802.5 specification. Like Ethernet, the Token Ring protocol provides services at the Physical and Data Link Layers of the OSI model. Token Ring networks can be run at two different data rates, 4 Mbps or 16 Mbps.

Unshielded Twisted Pair (UTP): UTP cable is similar to telephone cable, but has somewhat more stringent specifications regarding its suscept-ibility to outside EMI than common telephone wire. UTP is used much more often than STP.