Goal of Internet

The main goal of internetworking is to provide a universal service across heterogeneous networks.To provide universal service among all computers on an internet,routers must agree to forward information from a source on one network to the specified destination on the other network.The task is complex because as all we know that different frame formats and different addressing schemes are used by different networks.Hence,to overcome this problem protocol software is needed on computers and routers to make universal service possible.The main task of these internet protocols is to overcome the differences in frame formats and physical addresses to make communication possible among networks that use different technologies.
For knowing more about protocols for internetworking you can visit:
http://networkingconcepts4u.blogspot.com/2009/02/protocol-for-internetworking.html