April 28th, 2009 | Published in Google Research
[adapted from the speech given on the occasion of the honoris causa ceremony
at the Universidad Politecnico de Madrid]
The Internet is largely a software artifact and a layered one as my distinguished colleague, Sir Tim Berners-Lee has observed on many occasions. The layering has permitted a remarkable versatility in the implementation of the Internet and its applications. New technology can be used to implement each layer and as long as the interfaces between the layers remain static, the changes do not affect the functionality of the system. In this way, the Internet has evolved and adapted new transmission and switching technology into its lower layers and has supported new upper layers such as the HTTP, HTML and SSL protocols of the World Wide Web.
In recent years, the term “cloud computing” has emerged to make reference to the idea that from the standpoint of a device, say a laptop, on the Internet, many of the applications appear to be operating somewhere in the network “cloud.” Google, Amazon, Microsoft and others, as well as enterprise operators, are constructing these cloud computing centers. Generally, each cloud knows only about itself and is unaware of the existence of other cloud computing facilities. In some ways, cloud computing is like the networks of the 1960s when my colleagues and I began to think about connecting computers together on networks. Each network was typically proprietary. IBM had Systems Network Architecture; Digital Equipment Corporation had its DECNET; Hewlett-Packard had its Distributed System. These networks were specific to each manufacturer and did not interconnect nor even have a way to express the idea of connecting to another network. The Internet was the solution that Robert Kahn and I developed to allow all such networks to be interconnected in a uniform way.
Cloud computing is at the same stage. Each cloud is a system unto itself. There is no way to express the idea of exchanging information between distinct computing clouds because there is no way to express the idea of “another cloud.” Nor is there any way to describe the information that is to be exchanged. Moreover, if the information contained in one computing cloud is protected from access by any but authorized users, there is no way to express how that protection is provided and how information about it should be propagated to another cloud when the data is transferred.
Interestingly, my colleague, Sir Tim Berners-Lee, has been pursuing ideas that may inform the so-called “inter-cloud” problem. His idea of data linking may prove to be a part of the vocabulary needed to interconnect computing clouds. The semantics of data and of the actions one can take on the data, and the vocabulary in which these actions are expressed appear to me to constitute the beginning of an inter-cloud computing language. This seems to me to be an extremely open field in which creative minds everywhere can be free to contribute ideas and to experiment with new concepts. It is a new layer in the Internet architecture and, like the many layers that have been invented before, it is an open opportunity to add functionality to an increasingly global network.
There are many unanswered questions that can be posed about this new problem. How should one reference another cloud system? What functions can one ask another cloud system to perform? How can one move data from one cloud to another? Can one request that two or more cloud systems carry out a series of transactions? If a laptop is interacting with multiple clouds, does the laptop become a sort of “cloudlet”? Could the laptop become an unintended channel of information exchange between two clouds? If we implement an inter-cloud system of computing, what abuses may arise? How will information be protected within a cloud and when transferred between clouds. How will we refer to the identity of authorized users of cloud systems? What strong authentication methods will be adequate to implement data access controls?
Because the Internet is primarily a software artifact, there seems to be no end to its possibilities. It is an endless frontier, open to exploration by virtually anyone. I cannot guess what will be discovered in these explorations but I am sure that we will continue to be surprised by the richness of the Internet’s undiscovered territory in the decades ahead.