Q. Show Network Topology in digital system?

This deals with the geometrical arrangement of nodes (endpoints consisting of physical devices such as terminals, printers, PCs, andmainframes) interconnected by links (transmission channels). Network topologies may be classified as bus topology (multidrop topology), star topology, ring topology, tree topology, and distributed (mesh or hybrid) topology, as illustrated in Figure. Bus topology is used predominantly by LANs, whereas star topology is commonly used by private-branch exchange (PBX) systems. Ring topology may have centralized control (with one node as the controller) or decentralized control (with all nodes having equal status). Tree topology is used in most of the remote-access networks, whereas distributed topology is common in public and modern communications networks. A fully distributed network allows every set of nodes to communicate directly with every other set through a single link and provides an alternative route between nodes.

The Internet is physically a collection of packet switching networks interconnected by gateways along with protocols that allow them to function logically as a single, large, virtual network. Gateways (often called IP routers) route packets to other gateways until they can be delivered to the final destination directly across one physical network. Figure shows the structure of physical networks and gateways that provide interconnection. Gateways do not provide direct connections among all pairs of networks. The TCP/IP is designated to provide a universal interconnection among machines, independent of the particular network to which they are attached. Besides gateways that interconnect physical networks, as shown in Figure, Internet access software is needed on each host (any end-user computer system that connects to a network) to allow application programs to use the Internet as if it were a single, real physical network. Hosts may range in size from personal computers to supercomputers.