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Table of contents
of the current issue

Selected Highlights
The Future
Internet -
Challenges and initiatives

EU approach
towards the
Future Internet

EIFFEL - Shaping
the Future

Trilogy -
Architecting the Future Internet

France Telecom -
A possible vision
of the Future

Telenor - Where should the
Internet be

Interview with
online media
expert Philippe Martineau


Architecting the Future Internet

The Trilogy Project

Matthew Ford
BT Group plc

Philip Eardley
BT Group plc

The Internet is out-growing its original design. Evidence for this is widespread and the problem is affecting all the various stakeholders in different ways. End-users are plagued by spam and security worries; operators are spending ever more effort to mitigate the effects of address space depletion and the limitations of current inter-domain routing protocols; enterprises face complex trade-offs when trying to ensure resilience through multi-homing or protection from distributed denial-of-service attacks, and application developers have a mountain to climb in order to circumvent the presence of middleboxes in the end-to-end path. It is now the right time to develop a new design that is cognisant of the competing technical, economic and social demands that must be met by the global information network.

To re-architect the Internet in this way is no small undertaking, but that is precisely what the Trilogy project has set out to do. Launched at the beginning of 2008, Trilogy has a vision of a coherent, integrated and future-proof architecture that unifies the heterogeneous network, offering immediate deployment rewards coupled with long-term stability.

The Trilogy concept: architecture for change

There are two key ideas behind the Trilogy concept. The first is technical; the traditional separation between congestion control, routing mechanisms, and business demands (as reflected in policy) is the direct cause of many of the problems which are leading to a proliferation of control mechanisms, fragmentation of the network into walled gardens, and growing scalability issues. Re-architecting these mechanisms into a more coherent whole is essential if these problems are to be tackled (see figure 1).

Figure 1: Trilogy concept: architecture for change

The second key idea is more abstract, but fundamental. It recognises that the success of the Internet derives not directly from its transparency and self-configuration, but from the fact that it is architected for change. The Internet seamlessly supports evolution in application use and adapts to configuration changes; deficiencies have arisen where it is unable to accommodate new types of business relationship. To make the Internet richer and more capable will require more sophistication in its control architecture, but without imposing a single organisational model. Therefore, Trilogy’s key principles are to retain the ubiquity enabled by the hourglass model (see figure 2), and take the self-configuration philosophy one level further: we seek a control architecture for the new Internet that can adapt in a scalable, dynamic, autonomous and robust manner to local operational and business requirements.

Figure 2: The Internet's hourglass

Conclusion: an Internet hourglass for control

The design principles that have enabled the ubiquity and robustness of the Internet are simplicity and transparency: IP over everything and everything over IP. It has thus been simple to link any new network to the Internet, providing instant benefits resulting from the interconnectivity with a huge range of communicating peers; and the transparency of the Internet has facilitated the deployment of successively more complex network-agnostic applications and services. Together, these two attributes characterise the hourglass approach to network architecture. For the Internet, this hourglass approach has led directly to a virtuous circle of increased network reach enabling new styles of usage and vice versa (see figure 3).

Figure 3: A virtuous circle of new applications and network reach

Unfortunately, this hourglass picture omits the mechanisms needed for control, and while such mechanisms have proliferated, they are typically imprecise and inelegant solutions that work against the original benefits of the hourglass approach. Trilogy therefore seeks to design an hourglass control architecture for the Internet supporting extremes of commercial, social and technical control. The objective is bold: to re-architect the world’s ICT infrastructure by delivering a coherent set of changes solving technical and commercial problems together. You can find more information on Trilogy at

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