Computer Network - A set of computers connected together for the purpose of sharing resources.

Packet - A piece of a message transmitted over a packing-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) - computer network that extends over a large geographical distance

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. The MAC address, which is made up of two equal parts, is 6 bytes long. The first 3 bytes identify the company that made the NIC. The second 3 bytes are the serial number of the NIC itself.

IP Address - it is an identifier for a computer or device on a TCP/IP network. Networks using the TCP/IP protocol route messages based on the IP address of the destination. 

Bus Topology - Each node is connected one right after the other along the same backbone, similar to Christmas lights. 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.

Network Token - is a special series of bits that travels around a token-ring network. As the token circulates, computers attached to the network can capture it. The token acts like a ticket, enabling its owner to send a message across the network. 

Star Topology - 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. The hub is simply a junction that joins all the different nodes together.

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. The protocol determines the following:

The type of error checking to be used, data compression method, how the sending device will indicate that it has finished sending, how the receiving device will indicate that it has received a message.

Peer-to-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.