Computer Network system

The fundamental purpose of computer networks is to provide access to shared resources, most notably printers and data storage (both disk drives and tape drives). Local Area Networks (LANs) involve several primary components:

• Network interconnection (for example, copper wire, fiber optic cable, infrared, or radio).
• Network Interface Circuitry (NIC) in the individual personal computers, connected to the network. This circuitry may be part of the system motherboard or it may be on a separate plug-in card.
• The shared resources themselves, each with their own NIC connected to the network.
• Software on the individual personal computers that uses the NIC to access the shared resources. This software is typically arranged to present the appearance to the rest of the operating system that these resources are directly connected. In the jargon, "emulating local disks and printers."
• Software on the shared resource that coordinates with the software on the individual machines to provide access to the shared resources for the users of the multiple individual personal computers. This software is typically running on a computer system ("the server") to which the shared resources are directly attached, and is a multi-user operating system.

The most common case is for the server to be the same sort of personal computer hardware as the individual personal computers on the network (Intel or Macintosh). In this case, the operating system is called a "network operating system" to emphasize the difference from the single-user operating system of the personal computer. Novell is perhaps the most striking example of this approach.

Telecommunication Network system

A telecommunications network is a network telecommunication of links and nodes arranged so that messages may be passed from one part of the network to another over multiple links and through various nodes.

Telecommunications network links (including their endpoints or "nodes") may in turn be built out of hierarchical transmission systems.

Examples of telecommunications networks are:

• Computer networks
• Internet Network- The internet network is a global ‘network of networks’. The internet is connected via an Internet Service Provider (ISP) and then becomes part of a network. This network then connects to a larger corporate network that interconnects with several other similar networks through Network Access Points (NAPs).
• The public telecommunication network
• the global Telex network
• the aeronautical ACARS network

Telecommunication Network Components

All telecommunication networks are made up of five basic components that are present in each network environment regardless of type or use. These basic components include terminals, telecommunications processors, telecommunications channels, computers, and telecommunications control software.

Components used in Computer Network systems

Gateway

The internet is a communications system that routes packets based on internet addresses. A network's protocol specifies a common set of rules and/or signals which the networked devices use to communicate with each other. Gateways offer the advantage of IP telephony by bridging between the traditional telephone network and the Internet. Network firewalls provide important safeguards for any network connected to the Internet. A network gateway act as a firewall is that filters packets and separates an Intranet from Internet. A gateway acts as the interface between proximity local area protocols and wide area protocols. The internet gateway transfers the packets to the internet where internet routers forward the packets based on the internet address.

Router

A network router joins two computer networks together. DSL and cable modem routers are often used in homes and small businesses, while other types of network routers are also used on the Internet.

Linksys is one of the leading manufacturers of network routers for homes and small businesses. Linksys offers a wide range of networking products including both Ethernet and wireless routers.

Switch

Switch is a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. So unlike a hub a switch splits the network traffic and sends it to different destinations rather than to all systems on the network.

Hub

A special type of network device called the hub can be found in many home and small business networks. Though they've existed for many years, the popularity of hubs has exploded recently, especially among people relatively new to networking. A hub is a small rectangular box, often made of plastic, which receives its power from an ordinary wall outlet. A hub joins multiple computers (or other network devices) together to form a single network

Firewall

Firewall is a piece of hardware or software put on the network to prevent some communications forbidden by the network policy. A network firewall guards a computer network against unauthorized incoming messages or undesired outgoing messages. Network firewalls may be hardware devices, software programs, or a combination of the two.

Network Interface Card

A NIC, or Network Interface Card, is a circuit board or chip, which allows the computer to communicate to other computers on a Network. This board, when connected to a cable or other method of transferring data such as infrared, can share resources, information and computer hardware.

Local or Wide area networks are generally used for large businesses as well as are beginning to be found in homes as home users begin to have more than one computer. Utilizing network cards to connect to a network allow users to share data such as companies being able to have the capability of having a database that can be accessed all at the same time, send and receive e-mail internally within the company, or share hardware devices such as printers.

Server

In computing, a server is any combination of hardware or software designed to provide services to clients. When used alone, the term typically refers to a computer which may be running a server operating system, but is commonly used to refer to any software or dedicated hardware capable of providing services.

The word server is used quite broadly in information technology. Despite the many Server branded products available (such as Server editions of Hardware, Software and/or Operating Systems), in today's mass markets like Apple and Microsoft.