Modular expansion and reconfiguration of shufflenets in multi-star implementations.

by Philip Pak-tung To.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.Includes bibliographical references (leaves 57-60).Chapter 1 --- Introduction --- p.1Chapter 2 --- Modular Expansion of ShuffleNet --- p.8Chapter 2.1 --- Multi-Star Implementation of ShuffleNet --- p.10Chapter 2.2 --- Modular Expansion of ShuffleNet --- p.21Chapter 2.2.1 --- Expansion Phase 1 --- p.21Chapter 2.2.2 --- Subsequent Expansion Phases --- p.24Chapter 2.3 --- Discussions --- p.26Chapter 3 --- Reconfigurability of ShuffleNet in Multi-Star Implementation --- p.33Chapter 3.1 --- Reconfigurability of ShuffleNet --- p.34Chapter 3.1.1 --- Definitions --- p.34Chapter 3.1.2 --- Rearrangable Conditions --- p.35Chapter 3.1.3 --- Formal Representation --- p.38Chapter 3.2 --- Maximizing Network Reconfigurability --- p.40Chapter 3.2.1 --- Rules to maximize Tsc and Rsc --- p.41Chapter 3.2.2 --- Rules to Maximize Z --- p.42Chapter 3.3 --- Channels Assignment Algorithms --- p.43Chapter 3.3.1 --- Channels Assignment Algorithm for w = p --- p.45Chapter 3.3.2 --- Channels Assignment Algorithm for w = p. k --- p.46Chapter 3.3.3 --- Channels Assignment Algorithm for w=Mpk --- p.49Chapter 3.4 --- Discussions --- p.51Chapter 4 --- Conclusions --- p.5

Designing a multi-hop regular virtual topology for ultrafast optical packet switching : node placement optimisation and/or dilation minimisation?

This paper studies the design of multi-hop regular virtual topologies to facilitate optical packet switching in networks with arbitrary physical topologies. The inputs to the virtual topology design problem are the physical topology, the traffic matrix and the regular topology. In this paper, this problem is tackled directly and also by decomposition into two sub-problems. The first sub-problem, dilation minimisation, uses only the physical topology and the virtual topology as optimisation inputs. The second sub-problem considers the traffic matrix and virtual topology as optimisation inputs. The solutions of these two sub-problems are compared with each other and against the results obtained when the global problem is optimised (using all three possible input parameters) for a variety of traffic scenarios. This gives insight into the key question of whether the physical topology or the traffic matrix is the more important parameter when designing a regular virtual topology for optical packet switching. Regardless of the approach taken the problem is intractable and hence heuristics must be used to find (near) optimal solutions in reasonable time. Five different optimisation heuristics, using different artificial intelligence techniques, are employed in this paper. The results obtained by the heuristics for the three alternative design approaches are compared under a variety of traffic scenarios. An important conclusion of this paper is that the traffic matrix plays a less significant role than is conventionally assumed, and only a marginal penalty is incurred by disregarding it in several of the traffic cases considered

Nodal distribution strategies for designing an overlay network for long-term growth

Scope and Method of Study:This research looked at nodal distribution design issues associated with building an overlay network on top of an existing legacy network with overlay network switches and links not necessarily matching the switch and link locations of the underlying network. A mathematical model with two basic components, switch costs and link costs, was developed for defining the total cost of a network overlay. The nature of the underlying legacy topology determines the dominant factor, link or switch costs to the total cost function as well as the unit cost for switches and links.Findings and Conclusions:The three design heuristics presented first, locate overlay switches at nodes in the center of the legacy network as opposed to the periphery; second, locate overlay switches at legacy nodes with high connectivity; and third, locate overlay switches at legacy nodes with high traffic flow demands, can be used to help point to the direction of keeping costs under control when design changes are required. Applying the concept of efficient frontiers to the world of network design and building a suite of best designs gives the network designer greater insight into how to design the best network in the face of changing real-world constraints. For the cost model and the case studies evaluated using the design strategies in this study, distributed approaches generally tend to be a good choice when the link costs dominate the total cost function because total path distances and therefore link costs need to be minimized in preference over switch costs. A distributed overlay tends to have lower link costs because there is usually a greater probability that total path distances can be minimized because of greater connectivity. More connections set up the potential for more traffic flow path choices allowing each traffic flow to be sent along shorter paths. In legacy network topology designs that have many nodes with high connectivity, the overlay link costs can be relatively similar between designs and the switch costs can have a large impact upon total cost