Architectural Description based Overlay Networks

Abstract

Overlay Networks’ have been gaining popularity with an increasing number of applications being developed using them. Overlay networks follow heterogeneous architectures such as Peer to Peer, Client Server and Hybrid/Hierarchical Peer to Peer. In this work, the primary objective was to abstract the Overlay Network architecture into an ‘Architectural Description’. An Architectural Description document may contain the ‘Roles’ and the ‘Relationships’ of a particular Overlay Architecture. The Architectural Description documents may be exchanged among the nodes and executed by themselves. Upon execution, appropriate Roles and Relationships are adopted by the nodes. The Overlay Networks formed using the Roles and Relationships assigned by the Architectural Descriptions are called Architectural Description (AD) based Overlay Networks. In order to exchange the Architectural Descriptions among the nodes, a ‘Facilitating Network’ is used, which is again an Overlay Network. AD based Overlay Networks open many new possibilities in Overlay Networking, as it would substantially improve on the dynamic nature and the adaptability of Overlay Networks. A key advantage of using this approach is that it, allows Overlay Networks operating under heterogeneous architectures to work collaboratively. The nodes playing multiple roles can ‘glue together’ otherwise isolated Overlay Networks to facilitate this inter-operability. Also, the AD based approach would make it possible for the same set of nodes to run applications that operate on different Overlay Architectures, either simultaneously or at different time intervals. This would greatly improve the dynamic nature of Network Overlays, harnessing the full potential in them. Thus, working towards this interoperability is a key objective of this project. Another natural outcome of this approach is that multiple Overlays may be super-imposed on top of each other. This would enable the same set of nodes to belong to several Overlays simultaneously. Depending on the application that is being run, each node would have the ability to pick and choose the respective role from the available set of roles. Also, using this approach, the same set of nodes may follow heterogeneous Overlays at different time intervals depending on varying requirements. These features would increase the re-use of computing resources and make Overlay Networks more efficient and user-centric. Architectural Descriptions may also include Security Descriptions (Encryption algorithm, Key Size), which would be used to create ‘Security Roles’ that are adopted by the nodes. This would facilitate the Overlay Networks that are following different security settings, to collaborate, via the nodes that follow multiple Security Roles. Apart from that, Architectural Descriptions provide an effective means of security key exchange among the nodes, at the time of Overlay Network formation. With the above possibilities, AD based Overlay Networks open up exciting new avenues in Overlay Networking. In this work, the concept of AD based Overlay Networks was developed in order to explore the usages of such networks. A prototype framework and an application set were also developed to further demonstrate the possible applications of this approach. In the prototype, a distributed network of nodes was emulated in a PC environment. A separate client application was developed to observe the status of the nodes and the Overlays, and also to control the behavior of the nodes using AD documents and application-level commands. v In the prototype, each node would communicate with other nodes and the client application via Sockets. A node would have the ability to play multiple roles and be part of multiple relationships at the same time. As a result, it was possible to try out the original objectives of the project with regard to exploring the dynamic changing of Overlays, by changing the executed AD document. The prototype supports one Asymmetric and one Symmetric key encryption algorithm. Therefore, the prototype could be used for integrating AD based Overlays with heterogeneous security settings, and trying out different key distribution methods. An iterative approach was followed in developing the Prototype, focusing on one feature of AD based Overlays at a single iteration. This methodology helped in improving on the conceptual groundwork that was necessary to identify the key areas where this approach would be useful. While developing the prototype, several modifications were done on the initial idea of an Architectural Description. Thus, the prototype not only helped as a demonstration tool but also a tool for validating and improving on the concept of AD based Overlay Networks. This work lays preliminary groundwork of what could be a useful methodology that can be used in Overlay Networking, and Networking in general. Much more effort is needed to bring this concept into a real-world application framework. In doing so, bulk of the source code, techniques and practices that were used to develop the prototype framework may also be re-used. Moreover, strong emphasis was given on identifying the possible future improvements and exploring how this approach would be used in real-world applications, within the course of this project.