Computer Network

A network is a group of computers connected together in a way that allows information to be exchanged between the computers.

Packet

 A piece of a message transmitted over a packet-switching network.

Local Area Network (LAN)

Connects many devices that are relatively close to each other, usually in the same building. 

Wide Area Network (WAN)

Connects a smaller number of devices that can be many kilometers apart. 

Node

A node is anything that is connected to the network. While a node is typically a computer, it can also be something like a printer or CD-ROM tower.

Media Access Control (MAC)

This is the physical address of any device -- such as the NIC in a computer -- on the network. 

IP Address

Is an identifier for a computer or device on a TCP/IP network. 



Bus Topology

Each node is daisy-chained (connected one right after the other) along the same backbone. Information sent from a node travels along the backbone until it reaches its destination node. Each end of a bus network must be terminated with a resistor to keep the signal that is sent by a node across the network from bouncing back when it reaches the end of the cable.

Ring Topology

The end of the network comes back around to the first node, creating a complete circuit. In a ring network, each node takes a turn sending and receiving information through the use of a token. The token, along with any data, is sent from the first node to the second node, which extracts the data addressed to it and adds any data it wishes to send. Then, the second node passes the token and data to the third node, and so on until it comes back around to the first node again. Only the node with the token is allowed to send data. All other nodes must wait for the token to come to them.

Network Token

A token is a special series of bits that travels around a token-ring network. 



Star Topology

In a star network, each node is connected to a central device called a hub. The hub takes a signal that comes from any node and passes it along to all the other nodes in the network. A hub does not perform any type of filtering or routing of the data. It is simply a junction that joins all the different nodes together.

Tree Topology

A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable.

Protocol

An agreed-upon format for transmitting data between two devices. 

Peer-Peer Architecture

A type of network in which each workstation has equivalent capabilities and responsibilities. 

Client/Server Architecture

Is a network architecture in which each computer or process on the network is either a client or a server.