In communication networks, a node which comes from the Latin word nodus, ‘knot' is a connection point, either a redistribution point or a communication endpoint (some terminal equipment). The definition of a node depends on the network and protocol layer referred to. A physical network node is an active electronic device that is attached to a network, and is capable of sending, receiving, or forwarding information over a communications channel.
Apassive distribution point such as a distribution frame is consequently not a node. In network theory or graph theory, the term node refers to a point in a network topology .
Client
A client runs on different computers interconnected by a computer network. A client sends the receiver a message by the network, hence the client managers local resources such as a display, keyboards and local disks. an example of a client is a banking application that allows a clerk to access the account information on a central database server as it is an extension of the object-base program.
Sever
A server is an application running on a computer that delivers a service. For example, a web server will deliver web pages when requested by a browser (called client in this context). The way a server and a client dialogs is called a protocol. For instance, HTTP is the protocol used between a browser an a web server. Among the many services provided by the Internet servers are:
World Wide Web
the domain name system
e-mail
FTP file transfer
chat and instant messaging
voice communication
streaming audio and video
online gaming
Hub
A network hub or repeater hub is a device for connecting multiple twisted pair or fiber optic Ethernet devices together and thus making them act as a single network segment. Hubs work at the physical layer of the OSI model. The device is thus a form of multiport repeater. Repeater hubs also participate in collision detection, forwarding a jam signal to all ports if it detects a collision.
Hubs also often come with a BNC and/or AUI connector to allow connection to legacy 10BASE2 or 10BASE5 network segments. The availability of low-priced network switches has largely rendered hubs obsolete but they are still seen in older installations and more specialized applications.
Network Interface Cards
A network interface controller (NIC) is a hardware device that handles an interface to a computer network and allows a network-capable device to access that network. The NIC has a ROM chip that contains a unique number, the media access control (MAC) Address that is permanent. The MAC address identifies the device uniquely on the LAN. The NIC exists on both the 'Physical Layer' and the 'Data Link Layer' of the OSI model.
Sometimes the words 'controller' and 'card' are used interchangeably when talking about networking because the most common NIC is the network interface card. Although 'card' is more commonly used, it is less encompassing. The 'controller' may take the form of a network card that is installed inside a computer, or it may refer to an embedded component as part of a computer motherboard, a router, expansion card, printer interface or a USB device.
Network Operating System
A networking operating system is an operating system that contains components and programs that allow a computer on a network to serve requests from other computer for data and provide access to other resources such as printer and file systems.
Distributed prossessing
Distributed processing implies that processing will occur on more than one processor in order for a transaction to be completed. In other words, processing is distributed across two or more machines and the processes are most likely not running at the same time, i.e. each process performs part of an application in a sequence. Often the data used in a distributed processing environment is also distributed across platforms.
Host Computer
In computer networking, a network host, Internet host, host, or Internet node is a computer connected to the Internet - or more generically - to any type of data network. A network host can host information resources as well as application software for providing network services.
Every Internet host has one or more IP addresses uniquely assigned to the host. The addresses are assigned either manually by the computer administrator, or automatically at start-up by means of the Dynamic Host Configuration Protocol (DHCP).
Every host is a physical network node but not every physical network node is a host. Network devices such as modems and network switches are usually not assigned host addresses, and are not considered hosts. Devices such as network printers and hardware routers are assigned IP addresses, but since they are not general-purpose computers, they are sometimes not considered as hosts.
Network Maneger
NetworkManager is a software utility aimed at simplifying the use of computer networks on Linux and other Unix-like operating systems.NetworkManager is designed in two components: a service which manages connections and reports network changes, and a graphical desktop applet which allows the user to manipulate network connections. Both components are intended to be reasonably portable, and the applet is available to desktop environments
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