Part 1: The Goals of the Internet Architecture

Currently there is considerable interest (real and hype) in blockchain systems as a promising technology for the future infrastructure of a global value-exchange network – or whatsome refer to as the “Internet of value”. The original blockchain idea of Haber and Stornetta is now a fundamental construct within most blockchain systems, starting with the Bitcoin system which first adopted the idea and deployed it in a digital currency context.

Many parallels have been made between blockchain systems and the Internet. However,many comparisons often fail to understand the fundamental goals of the Internet architecture as promoted and led by DARPA, and thus fail to fully appreciate how these goals have shaped the Internet to achieve its success as we see it today. There was a pressing need in the Cold War period of the 1960s and 1970s to develop a new communications network architecture that did not previously exist, one that would allow communications to survive in the face of attacks.

If blockchain technology seeks to be a fundamental component of the future global distributed network of commerce and value, then its architecture must also satisfy the same fundamental goals of the Internet architecture.

In considering the future direction for blockchain systems generally, it is useful to recall and understand goals of the Internet architecture as defined in the early 1970s as a project funded by DARPA. The definition of the Internet as view in the late 1980s is the following: it is “a packet switched communications facility in which a number of distinguishable networks are connected together using packet switched communications processors called gateways which implement a store and forward packet-forwarding algorithm”.

It is important to remember that the design of the ARPANETand the Internet  favored  military values (e.g. survivability, flexibility, and high performance) over commercial goals (e.g. low cost, simplicity, or consumer appeal), which in turn has affected how the Internet has evolved and has been used. This emphasis was understandable given the Cold War backdrop to the packet-switching discourse throughout the 1960s and1970s.

The DARPA view at the time was that there are seven (7) goals of the Internet architecture, with the first three being fundamental to the design, and the remaining four being second level goals. The following are the fundamental goals of the Internet in the order of importance:

1. Survivability: Internet communications must continue despite loss of networks or gateways. This is the most important goal of the Internet, especially if it was to be the blueprint for military packet switched communications facilities. This meant that if two entities are communicating overthe Internet, and some failure causes the Internet to be temporarily disrupted and reconfigured to reconstitute the service, then the entities communicating should be able to continue without having to reestablish or reset the high level state of their conversation. Therefore to achieve this goal, the state information which describes the on-going conversation must be protected. But more importantly, in practice this explicitly meant that it is acceptable to lose the state information associated with an entity  if, at the same time, the entity itself is lost.
2. Variety of service types: The Internet must support multiple types of communications service. What was meant by “multiple types” is that at the transport level the Internet architecture should support different types of services distinguished by differing requirements for speed, latency and reliability. Indeed it was this goal that resulted in the separation into two layers of the TCP layer and IP layer, and the use of bytes (not packets) at the TCP layer for flow control and acknowledgement.
3. Variety of networks: The Internet must accommodate a variety of networks. The Internet architecture must be able to incorporate and utilize a wide variety of network technologies, including military and commercial facilities.

The remaining four goals of the Internet architecture are: (4) distributed management of resources, (5) cost effectiveness, (6) ease of attaching hosts, and (7) accountability in resource usage.Over the following decades these second level goals have been addressed in in different ways.

[The latest version of the full paper can be downloaded here]