The internet Concept

• With all the different approaches to networking we have considered, it should be clear that one of the problems facing the effective use of networks is simply that there are too many kinds of networks.

• To provide the sort of global communication possible through the Internet, we need to provide mechanisms that enable machines connected to networks based on distinct technologies and protocols to communicate.

• IEEE 802.1 bridges represent a modest effort in this direction, but:

  • They depend on the fact that the networks they may interconnect are not too dissimilar (i.e. same address formats).

  • They depend on algorithms that limit the usable portions of the extended networks topology.

  • They represent an approach that would not scale well.

    • To make it possible to interconnect N different types of networks, one would need to market N(N-1) different types of bridges.

• The Internet is based on a different approach to interconnecting dissimilar networks.

  • Rather than simply translating frames of one existing protocol format to another, the Internet is based on defining a new "virtual network" protocol -- the iP (or internet protocol).

  • Given the common language represented by the iP, one only needs 2N converters. N that convert from the existing protocols to iP and N that convert from iP to the existing protocols.