There are a number of ways or topologies of connecting computers each having its own merits and demerits.
The bus topology uses a single cable as a bus to which all computers are connected. The failure of a single node doesn’t disrupt the communication between the remaining nodes.
The star topology uses a central hub to which all nodes are connected. Because network traffic passes through the hub, the entire network fails if the hub fails to work On the other hand, new nodes can be added without disrupting the service.
Nodes using the ring topology are connected in a closed loop without using a hub. Data moves from one node to the next one which examines each packet to determine whether it should be allowed moving further on to the next node. For uni-directional rings, failure of one node causes the network to shut down.
Nodes in a mesh topology are connected to one another, offering a choice of multiple routes for data to travel. When a node breaks down, the packet simply changes its route. This is the most expensive of all the topologies, and is found mainly in corporate networks.
Networks are also classified based on their size. The two most common types are the Local Area Network (LAN) and Wide Area Network (WAN) .
LANs are used by small organizations where the area of operation is confined to one building. They generally use Ethernet technology. The newer Wireless LAN (WLAN), also known as Wi-Fi, has become a serious contender to the wired LAN Standard Ethernet speeds are ruling at 100 Mbps. Wi-Fi networks using 802.11g operate at around 20 Mbps.
WAN’s extend the range used by LANs. It can connect a number of cities or establishments in the same city. Because of the large distances, optic fiber cables, leased telephone lines and radio transmission are used to connect WAN nodes. WANs can also be formed by interconnecting LANs using routers (1.153). Banks, airline and hotel reservation companies use WANs for their real-time operations. The Internet is the largest WAN in the world.
Technology advances have led to the birth of other types of networks. They are briefly discussed as follows
• Metropolitan Area Network (MAN)
This type is sandwiched between LAN and a WAN A MAN is employed for interconnecting computers in the same city.
• Campus Area Network (CAN)
This is smaller than MAN, and it is used to connect an entire university campus.
• Personal Area Network (PAN)
This is the smallest network of all and has only recently come of age. A PAN operates within a range of a few meters. It connects small devices like cellphones and laptops with infrared or Bluetooth technology.
The Internet and internet
The Internet (also called Net) is the largest wide area network on the planet It is a collection of over 50,000 networks that run a special set of network protocols called TCP/IP. Born in 1983 at the behest of the US Ministry of Defence, it is today a self-governing network without an owner The Internet is different from other networks; it grows continuously without disturbing the existing structure.
The hardware technology used by the Internet is no different from any LAN or WAN. For this reason, it is possible to create small networks of this type that can replicate its services, albeit on a much smaller scale. This network that runs the same set of network protocols is called an internet (with lowercase “I” or intranet. Depending on the way it is configured, an internet may or may not have access to the Internet The addresses used by internet nodes are not valid on the Internet