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. 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)

 Local area network (LAN) technologies connect many devices that are relatively close to each other, usually in the same building.

Wide Area Network (WAN)

Wide area network(WAN) technologies connect 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. 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

IP address is short for Internet Protocol (IP) address. An 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

Like a bus network, rings have the nodes daisy-chained. The difference is that 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.

Token

 A token could be a keyword, an operator, or a punctuation mark,a special series of bits that travels around a token-ring network, or a small device the size of a credit card that displays a constantly changing ID code

Star Topology

Star bus combines elements of the star and bus topologies to create a versatile network environment. Nodes in particular areas are connected to hubs (creating stars), and the hubs are connected together along the network backbone (like a bus network). Quite often, stars are nested within stars

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-to-peer architecture

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 others. Peer-to-peer networks are generally simpler, but they usually do not offer the same performance under heavy loads.

Client-server architecture 

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