NETWORK TOPOLOGY

The network topology defines the way in which computers, printers, and other devices are connected, physically and logically. A network topology describes the layout of the wire and devices as well as the paths used by data transmissions. Commonly used topologies include:

• Bus
• Star
• Tree (hierarchical)
• Linear
• Ring
• Mesh
• partially connected
• fully connected (sometimes known as fully redundant)

The network topologies mentioned above are only a general representation of the kinds of topologies used in computer network and are considered basic topologies.

WIRELESS NETWORKS ( WLAN ,WWAN )

A wireless network is basically the same as a LAN or a WAN but there are no wires between hosts and servers. The data is transferred over sets of radio transceivers. These types of networks are beneficial when it is too costly or inconvenient to run the necessary cables. For more information, see Wireless LAN and Wireless wide area network. The media access protocols for LANs come from the IEEE.

The most common IEEE 802.11 WLANs cover, depending on antennas, ranges from hundreds of meters to a few kilometers. For larger areas, either communications satellites of various types, cellular radio, or wireless local loop (IEEE 802.16) all have advantages and disadvantages. Depending on the type of mobility needed, the relevant standards may come from the IETF or the ITU.

 

METROPOLITAN AREA NETWORK

A metropolitan network is a network that is too large for even the largest of LAN's but is not on the scale of a WAN. It also integrates two or more LAN networks over a specific geographical area ( usually a city ) so as to increase the network and the flow of communications. The LAN's in question would usually be connected via "backbone" lines.

WIDE AREA NETWORK(WAN)

A wide area network is a network where a wide variety of resources are deployed across a large domestic area or internationally. An example of this is a multinational business that uses a WAN to interconnect their offices in different countries. The largest and best example of a WAN is the Internet, which is a network comprised of many smaller networks. The Internet is considered the largest network in the world. The PSTN (Public Switched Telephone Network) also is an extremely large network that is converging to use Internet technologies, although not necessarily through the public Internet.

A Wide Area Network involves communication through the use of a wide range of different technologies. These technologies include Point-to-Point WANs such as Point-to-Point Protocol (PPP) and High-Level Data Link Control (HDLC), Frame Relay, ATM (Asynchronous Transfer Mode) and Sonet (Synchronous Optical Network). The difference between the WAN technologies is based on the switching capabilities they perform and the speed at which sending and receiving bits of information (data) occur.

LOCAL AREA NETWORK (LAN)

A local area network is a network that spans a relatively small space and provides services to a small number of people.

    A peer-to-peer or client-server method of networking may be used. A peer-to-peer network is where each client shares their resources with other workstations in the network. Examples of peer-to-peer networks are: Small office networks where resource use is minimal and a home network. 

    A client-server network is where every client is connected to the server and each other. Client-server networks use servers in different capacities. 

    These can be classified into two types:

           1. Single-service servers

           2. print server,

    where the server performs one task such as file server, ; while other servers can not only perform in the capacity of file servers and print servers, but they also conduct calculations and use these to provide information to clients (Web/Intranet Server). Computers are linked via Ethernet Cable, can be joined either directly (one computer to another), or via a network hub that allows multiple connections.

NETWORKING METHODS

Networking is a complex part of computing that makes up most of the IT Industry. Without networks, almost all communication in the world would cease to happen. It is because of networking those telephones, televisions, the internet, etc. work.

One way to categorize computer networks is by their geographic scope, although many real-world networks interconnect Local Area Networks (LAN) via Wide Area Networks (WAN)and wireless networks[WWAN]. 

HISTORY OF COMPUTER NETWORKING

Before the advent of computer networks that were based upon some type of telecommunications system, communication between calculation machines and early computers was performed by human users by carrying instructions between them. Many of the social behavior seen in today's Internet was demonstrably present in nineteenth-century telegraph networks, and arguably in even earlier networks using visual signals.

In September 1940 George Stibitz used a teletype machine to send instructions for a problem set from his Model K at Dartmouth College in New Hampshire to his Complex Number Calculator in New York and received results back by the same means. Linking output systems like teletypes to computers was an interest at the Advanced Research Projects Agency (ARPA) when, in 1962, J.C.R. Licklider was hired and developed a working group he called the "Intergalactic Network", a precursor to the ARPAnet.

In 1964, researchers at Dartmouth developed the Dartmouth Time Sharing System for distributed users of large computer systems. The same year, at MIT, a research group supported by General Electric and Bell Labs used a computer (DEC's PDP-8) to route and manage telephone connections.

Throughout the 1960s Leonard Kleinrock, Paul Baran and Donald Davies independently conceptualized and developed network systems which used data grams or packets that could be used in a packet switched network between computer systems.

1965 Thomas Merrill and Lawrence G. Roberts created the first wide area network(WAN).

The first widely used PSTN switch that used true computer control was the Western Electric 1ESS switch, introduced in 1965.

In 1969 the University of California at Los Angeles, SRI (in Stanford), University of California at Santa Barbara, and the University of Utah were connected as the beginning of the ARPANet network using 50 kbit/s circuits. Commercial services using X.25, an alternative architecture to the TCP/IP suite, were deployed in 1972.

Computer networks, and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks from the researcher to the home user.

Today, computer networks are the core of modern communication. For example, all modern aspects of the Public Switched Telephone Network (PSTN) are computer-controlled, and telephony increasingly runs over the Internet Protocol, although not necessarily the public Internet. The scope of communication has increased significantly in the past decade and this boom in communications would not have been possible without the progressively advancing computer network.