Thomas Phillip Knudsen

Topological routing in large-scale networks

A new routing scheme, Topological Routing, for large-scale networks is proposed. It allows for efficient routing without large routing tables as known from traditional routing schemes. It presupposes a certain level of order in the networks, known from. Structural QoS. The main issues in applying Topological Routing to large-scale networks are discussed. Hierarchical extensions are presented along with schemes for shortest path routing, fault handling and path restoration. Further research in the area is discussed and perspectives on the prerequisites for practical deployment of Topological Routing in large-scale networks are given.

Applying 4-regular grid structures in large-scale access networks

4-Regular grid structures have been used in multiprocessor systems for decades due to a number of nice properties with regard to routing, protection, and restoration, together with a straightforward planar layout. These qualities are to an increasing extent demanded also in large-scale access networks, but concerning protection and restoration these demands have been met only to a limited extent by the commonly used ring and tree structures. To deal with the fact that classical 4-regular grid structures are not directly applicable in such networks, this paper proposes a number of extensions concerning restoration, protection, scalability, embeddability, flexibility, and cost. The extensions are presented as a tool case, which can be used for implementing semi-automatic and in the longer term full automatic network planning tools.

Combining wired and wireless networks for a QoS-aware broadband infrastructure

We show how integrated planning of wired and wireless infrastructures can be used to build a QoS-aware broadband infrastructure. The outset is a case study of the municipality of Hals, a rural community in Denmark, where the objective is to establish a broadband infrastructure reaching all households and businesses. Two factors are considered particularly important when designing an infrastructure: the chosen technology must allow for sufficient bandwidth, and the physical network structures must allow for independent paths between any pair of nodes. A final solution is obtained by using fiber to the home for primary connections and fixed wireless access for backup. This is implemented over 15 years, during which temporary solutions ensure sufficient QoS and reliability for all users. These temporary solutions form parts of the final solutions.

Reliability demands in FTTH access networks

In this paper reliability and bandwidth demands of existing, new and expected classes of applications running over Fiber To The Home (FTTH) networks to private users and small enterprises are analysed and discussed. Certain applications such as home security and telemedicine are likely to require high levels of reliability in the sense that the demands for network availability are high; even short times without connectivity are unacceptable. To satisfy these demands, physical redundancy in the networks is needed. It seems to be the case that-at least in the short term-most reliability-critical applications do not require much bandwidth. This implies that redundancy do not need to be by fiber, but can be ensured by e.g. coax, copper or wireless solutions. However, implementing these solutions need careful planning to ensure the physical redundancy. In the long term, it is more likely that physical redundancy by fiber will be requested, either due to reliability-critical bandwidth-critical applications or due to the general dependency on network connections. The paper is ended by a discussion and suggestions for further research. In particular, further research in combined wired/wireless networks and implementations of fiber redundancy is encouraged

Scenario based network infrastructure planning

The paper presents a method for IT infrastructure planning that take into account very long-term developments in usages. The method creates a scenario for a final, time independent stage in the planning process. The method abstracts relevant modeling factors from available information; this includes available statistical information and a short survey of emerging technologies. A scenario for Denmark is presented and consequences are discussed

Designing broadband access networks with triple redundancy

An architecture is proposed for designing broadband access networks, which offer triple redundancy to the end users, resulting in networks providing connectivity even in case of any two independent node or line failures. Two physically independent connections are offered by fiber, and the last provided by some wireless solution. Based on experience with planning Fiber To The Home, the architecture is designed to meet a number of demands, making it practicable and useful in real-world network planning. The proposed wired topology is planar, and suitable for being fitted onto the road network without compromising line independency, and it can be implemented step-wise, the first step being based on a simple ring/tree topology. The double ring is used for the distribution network, ensuring 3-connectivity and making it feasible to use for connecting the base stations of the wireless network. Another advantage of using the double ring is that it allows for embedding other more advanced topologies such as the generalized Petersen graphs without changing ducts and placement of nodes.