The central issue this paper focuses on is developing a protocol to facilitate the interconnection of heterogeneous networks. The principal contribution, then, is the development of the Transmission Control Program for implementing datagram communication. The proposed protocol has risen to ubiquity and has facilitated a revolution in information technology. The findings of this paper were thus of great importance and will be for some time.
The key main ideas cited in this paper relate to solving the interconnection problem. First, the authors propose a gateway architecture to support interoperability among internally heterogeneous networks. End to end processing, along with the gateways, will provide transmission control by implementing an addressing scheme, datagram formatting, routing, and retransmission or duplicate detection. By way of rating these ideas, one is forced to confer 'breakthrough' status as the ideas in this paper have contributed to a global transformation.
One issue not addressed in this paper is support for different types of internetwork services to be provided. The handshake connections and duplicate / retransmission detection represent significant overhead which may not be necessary for all communications. The addressing and routing scheme, of course, eventually separated from this reliable protocol to provide for such unreliable communications. In addition, the authors state the eight bits to allow up to 256 distinct networks should be sufficient. Clearly, the scope of their idea far exceeded even the authors own expectations.