Routers, Switches, Hubs, Servers, Clients and NIC's
What is a network?
A computer network, or simply a network, is a collection of computers and other hardware devices interconnected by communication channels that allow sharing of resources, data formats and information. Where at least one process in one device is able to send/receive data to and from at least one computer or hardware device once this has happened and devices can send and receive data and information, then the two devices are said to be in a network. Another definition of a network is a group of devices connected to each other via many forms of communication systems.
What is a router?
A router is specialized computer connected to more than one network running software that allows the router to move data from one network to another. Routers operate at the network core for internet and broadband. The primary function of a router is to connect networks together and keep certain kinds of broadcast traffic under control. There are several companies that make routers: Cisco, Juniper, Nortel, BT and HP are just a few.
What is a network switch?
A network switch is a computer networking device that links network segments or network devices. A switch is a telecommunication device that receives a message from any device connected to it and then transmits the message only to the device for which the message was meant. This makes the switch a more intelligent device than a hub (which receives a message and then transmits it to all the other devices on its network). The network switch plays a very important part in most modern Ethernet local area networks (LANs). Mid-to-large sized LANs contain a number of linked switches. A switch basically means you can run a whole network on many many computers without having to set a different one up each time, so a switch can supply networks from 2 - 100s of computers depending on how many ports it has.
What is a hub?
An Ethernet hub, active hub, network hub, repeater hub, multiport repeater or hub is a device for connecting multiple Ethernet devices together and making them act as a single network. It has multiple input/output (I/O) ports, in which a signal introduced at the input of any port appears at the output of every port except the original incoming. A network hub is an unsophisticated device in comparison with, for example, a switch. A hub does not examine or manage any of the traffic that comes through it: any packet entering any port is rebroadcast on all other ports.
What are servers?
In most common use, a server is a physical computer (a computer hardware system) dedicated to run one or more services (as a host), to serve the needs of the users of other computers on a network. Depending on the computing service that it offers it could be a database server, file server, mail server, print server, web server, gaming server, or some other kind of server.
In the context of client server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the server performs some computational task on behalf of "clients." The clients either run on the same computer, or they connect through the network. Servers often provide essential services across a network, either to private users inside a large organization or to public users via the internet. A network server is a computer designed to process requests and deliver data to other (client) computers over a local network or the Internet. Network servers typically are configured with additional processing, memory and storage capacity to handle the load of servicing clients.
What are clients?
A client is a piece of computer hardware or software that accesses a service made available by a server. The server is often (but not always) on another computer system, in which case the client accesses the service by way of a network. A client is a computer program that, as part of its operation, relies on sending a request to another computer program (which may or may not be located on another computer). The term "client", however, may also be applied to computers or devices that run the client software or users that use the client software. For example, web browsers are clients that connect to web servers and retrieve web pages for display. Email clients retrieve email from mail servers. Online uses a variety of clients, which vary depending on the chat protocol being used. Multiplayer or online video games may run as a client on each computer.
what is a NIC?
A network interface controller (also known as a network interface card, network adapter, LAN adapter and by similar terms) is a computer hardware component that connects a computer to a computer network. Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus; the low cost of the Ethernet standard means that most newer computers have a network interface built into the motherboard.