Review: The Design Philosophy of the DARPA Internet Protocols

The paper, “The Design Philosophy of the DARPA Internet Protocols” by David D. Clark [1] presents the reasons, perhaps the goals which explain the Internet's current architecture. The fundamental goal of the Internet base on the paper is: “...to develop an effective technique for multiplexed utilization of existing interconnected networks.” For multiplexing to be made possible, packet switching technique is used, a fundamental component of the Internet architecture.

Moreover, a list of second level goals is also established as a guide for Internet's architecture and each item is discussed in detail. The list consists of 7 additional goals mentioned in order of importance:

1. Internet communication must continue despite loss of networks or gateways.

2. The Internet must support multiple types of communications service.

3. The Internet architecture must accommodate a variety of networks.

4. The Internet architecture must permit distributed management of its resources.

5.The Internet architecture must be cost effective.

6. The Internet architecture must permit host attachment with a low level of effort.

7. The resources used in the Internet architecture must be accountable.

The first second level goal is achieved using an approach called “fate-sharing” in which only the end-hosts maintain the state information about their connection. The top level goals (first 3) resulted in the development and use of datagrams as transporters across the network while the remaining low level goals are taken into minimum account. The paper concludes by upholding the success of the current Internet architecture because of its wide range of military and commercial utilization. Also, it suggests further development of the current datagram to achieve the low level goals (resource management and accountability) as well.

The author of the paper clearly stated the reasons why the Internet was designed in that certain way. He also did a great job of introducing a protocol feature and expounding it for each goal such as packet switching and the use of a datagram as a building block. I especially commend him for suggesting that a better building block might be suited for the next generation of architecture. He is aware of the fact that indeed datagrams came from the requirements of the DARPA project.

Today, we must look at the usage of the Internet very differently from the date that it was constructed. An example would be the increasing multimedia traffic and mobility services. We must again question Internet's design and look for what best suits the needs of today's network community.

Reference:

[1] David D. Clark, "The Design Philosopy of of the DARPA Internet Protocols." ACM SIGCOMM Computer Communications Review, vol.18, issue 4, August 1998.