IP/ATM solution for accelerating Internet services

Abstract

The Internet consists of IP routers which communicate with each other by means of distributed routing protocols. Routers use the collected information in order to make appropriate decisions regarding forwarding. On the Internet, Web navigation, file downloading and e-mail use the same protocol. Indeed, as regards IP routers, all these operations use IP datagrams. Routers have two main functions: path determination and packet routing (forwarding). Path determination is a function including the collection of network data, the preliminary processing of paths and the storage in a routing local table of the information specifying the next node on the way to its destination. The network information type depends on the routing protocol that is used. Distance-vector protocols (i.e. RIP, Routing Information Protocol) compute the number of routers before reaching the destination, whereas link-state protocols (i.e. OSPF, Open Shortest Path First) set up a local topological map of the used network that is aimed at sorting out the shortest path. The routing table is a list of all the destination networks that are declared (i.e. some masked IP addresses) with their immediate adjacent matching routers. Forwarding consists of taking a packet, looking at its destination address, consulting the routing table, and sending the packet to the appropriate output port according to the routing table information.