Packet - A piece of a message transmitted over a packet-switching network. See under packet switching. One of the key features of a packet is that it contains the destination address in addition to the data. In IP networks, packets are often called datagrams.

Local Area Network - (LAN) technologies connect many devices that are relatively close to each other, usually in the same building. The library terminals that display book information would connect over a local area network.

Wide Area Network - (WAN) technologies connect a smaller number of devices that can be many kilometers apart.

An IP (Internet Protocol) Address - is an alphanumeric label assigned to computers and other devices that connect to a network using an internet protocol. This address allows these devices to send and receive data over the internet. Every device that is capable of connecting to the internet has a unique IP address.

Token - In programming languages, a single element of a programming language. For example, a token could be a keyword, an operator, or a punctuation mark. In networking, a 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. There is only one token for each network, so there is no possibility that two computers will attempt to transmit messages at the same time.

Tree - 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. The protocol determines the following:

Peer-to-Peer Architectures - a type of network in which each workstation has equivalent capabilities and responsibilities. This differs from client/server architectures, in which some computers are dedicated to serving the other machines in the system. Peer-to-peer networks are generally simpler, but they usually do not offer the same performance under heavy loads.

Client-server architecture (client/server) is a network architecture in which each computer or process on the network is either a client or a server.