Network nodesĪpart from any physical transmission medium there may be, networks comprise additional basic system building blocks, such as network interface controller (NICs), repeaters, hubs, bridges, switches, routers, modems, and firewalls. In that case the packet is queued and waits until a link is free. Often the route a packet needs to take through a network is not immediately available. Typically, control information is found in packet headers and trailers, with payload data in between. The control information provides data the network needs to deliver the user data, for example: source and destination network addresses, error detection codes, and sequencing information. Packets consist of two kinds of data: control information, and user data (payload).
When one user is not sending packets, the link can be filled with packets from others users, and so the cost can be shared, with relatively little interference, provided the link isn’t overused. With packets, the bandwidth of the transmission medium can be better shared among users than if the network were circuit switched. Once the packets arrive they are reassembled into their original message.
In packet networks, the data is formatted into packets that are sent through the network to their destination. A network packet is a formatted unit of data (a list of bits or bytes, usually a few tens of bytes to a few kilobytes long) carried by a packet-switched network. However, most information in computer networks is carried in packets. Network packetĬomputer communication links that do not support packets, such as traditional point-to-point telecommunication links, simply transmit data as a bit stream. A computer network may be used by computer crackers to deploy computer viruses or computer worms on devices connected to the network, or to prevent these devices from accessing the network via a denial of service attack. Distributed computing uses computing resources across a network to accomplish tasks. Users may access and use resources provided by devices on the network, such as printing a document on a shared network printer. A network allows sharing of network and computing resources. A network allows sharing of files, data, and other types of information giving authorized users the ability to access information stored on other computers on the network. Providing access to information on shared storage devices is an important feature of many networks. PropertiesĬomputer networking may be considered a branch of electrical engineering, telecommunications, computer science, information technology or computer engineering, since it relies upon the theoretical and practical application of the related disciplines.Ī computer network facilitates interpersonal communications allowing users to communicate efficiently and easily via various means: email, instant messaging, chat rooms, telephone, video telephone calls, and video conferencing. carried as payload) over other more general communications protocols. In most cases, application-specific communications protocols are layered (i.e. Two such devices can be said to be networked together when one device is able to exchange information with the other device, whether or not they have a direct connection to each other.Ĭomputer networks differ in the transmission medium used to carry their signals, the communications protocols to organize network traffic, the network’s size, topology and organizational intent.Ĭomputer networks support an enormous number of applications and services such as access to the World Wide Web, digital video, digital audio, shared use of application and storage servers, printers, and fax machines, and use of email and instant messaging applications as well as many others. Nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Network computer devices that originate, route and terminate the data are called network nodes.
The best-known computer network is the Internet. The connections between nodes are established using either cable media or wireless media. In computer networks, networked computing devices exchange data with each other using a data link. Chapter 14: The Dynamics of Digital WorkĬhapter 2: Hardware, Software, and Networking 9 Computer NetworksĪ computer network or data network is a telecommunications network which allows computers to exchange data. Chapter 8: Net Neutrality and the Digital Divideģ5. Cognitive Science & Artificial Intelligence Chapter 2: Hardware, Software, and Networkingġ8. Case Study: Terrorist Usage of Social MediaĢ6. Artificial Intelligence and Machine Learning 2. Information Science Careers and Fields
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