Professor Iain Stewart's Outputs (67)

Reconfigurable routing in data center networks (2025)
Journal Article
Stewart, I., & Kutner, D. (2025). Reconfigurable routing in data center networks. Theoretical Computer Science, 1038, Article 115154

A hybrid network is a static (electronic) network that is augmented with optical switches. The Reconfigurable Routing Problem (RRP) in hybrid networks is the problem of finding settings for the optical switches augmenting a static network so as to ac... Read More about Reconfigurable routing in data center networks.

Reconfigurable routing in data center networks (2024)
Presentation / Conference Contribution
Kutner, D. C., & Stewart, I. A. (2024, September). Reconfigurable routing in data center networks. Presented at 20th International Symposium on Algorithmics of Wireless Networks, ALGOWIN 2024, Egham, UK

A hybrid network is a static (electronic) network that is augmented with optical switches. The Reconfigurable Routing Problem (RRP) in hybrid networks is the problem of finding settings for the optical switches augmenting a static network so as to ac... Read More about Reconfigurable routing in data center networks.

Payment Scheduling in the Interval Debt Model (2024)
Journal Article
Stewart, I., Kutner, D., Friedetzky, T., Trehan, A., & Mertzios, G. (2025). Payment Scheduling in the Interval Debt Model. Theoretical Computer Science, 1028, Article 115028. https://doi.org/10.1016/j.tcs.2024.115028

The network-based study of financial systems has received considerable attention in recent years but has seldom explicitly incorporated the dynamic aspects of such systems. We consider this problem setting from the temporal point of view and introduc... Read More about Payment Scheduling in the Interval Debt Model.

Payment scheduling in the Interval Debt Model (2023)
Presentation / Conference Contribution
Friedetzky, T., Kutner, D., Mertzios, G., Stewart, I., & Trehan, A. (2023, January). Payment scheduling in the Interval Debt Model. Presented at 48th International Conference on Current Trends in Theory and Practice of Computer Science (SOFSEM 2023), Novy Smokovec, Slovakia

The networks-based study of financial systems has received considerable attention in recent years, but seldom explicitly incorporated the dynamic aspects of such systems. We consider this problem setting from the temporal point of view, and we introd... Read More about Payment scheduling in the Interval Debt Model.

Using semidirect products of groups to build classes of interconnection networks (2020)
Journal Article
Stewart, I. (2020). Using semidirect products of groups to build classes of interconnection networks. Discrete Applied Mathematics, 283, 78-97. https://doi.org/10.1016/j.dam.2019.12.014

We build a framework within which we can define a wide range of Cayley graphs of semidirect products of abelian groups, suitable for use as interconnection networks and which we call toroidal semidirect product graphs. Our framework encompasses vario... Read More about Using semidirect products of groups to build classes of interconnection networks.

Variational networks of cube-connected cycles are recursive cubes of rings (2020)
Journal Article
Stewart, I. (2020). Variational networks of cube-connected cycles are recursive cubes of rings. Information Processing Letters, 157, Article 105925. https://doi.org/10.1016/j.ipl.2020.105925

In this short note we show that the interconnection networks known as variational networks of cube-connected cycles form a sub-class of the recursive cubes of rings.

Relating the bisection width of dual-port, server-centric datacenter networks and the solution of edge-isoperimetric problems in graphs (2019)
Journal Article
Erickson, A., Navaridas, J., & Stewart, I. (2020). Relating the bisection width of dual-port, server-centric datacenter networks and the solution of edge-isoperimetric problems in graphs. Journal of Computer and System Sciences, 108, 10-28. https://doi.org/10.1016/j.jcss.2019.08.005

Stellar datacenter networks are a recent generic construction designed to transform a base-graph into a dual-port, server-centric datacenter network. We prove that the S-bisection width of any stellar datacenter network can be obtained from the solut... Read More about Relating the bisection width of dual-port, server-centric datacenter networks and the solution of edge-isoperimetric problems in graphs.

INRFlow: An interconnection networks research flow-level simulation framework (2019)
Journal Article
Navaridas, J., Pascual, J. A., Erickson, A., Stewart, I. A., & Luján, M. (2019). INRFlow: An interconnection networks research flow-level simulation framework. Journal of Parallel and Distributed Computing, 130, 140-152. https://doi.org/10.1016/j.jpdc.2019.03.013

This paper presents INRFlow, a mature, frugal, flow-level simulation framework for modelling large-scale networks and computing systems. INRFlow is designed to carry out performance-related studies of interconnection networks for both high performanc... Read More about INRFlow: An interconnection networks research flow-level simulation framework.

The influence of datacenter usage on symmetry in datacenter network design (2017)
Journal Article
Stewart, I., & Erickson, A. (2018). The influence of datacenter usage on symmetry in datacenter network design. Journal of Supercomputing, 74(6), 2276-2313. https://doi.org/10.1007/s11227-017-2217-1

We undertake the first formal analysis of the role of symmetry, interpreted broadly, in the design of server-centric datacenter networks. Although symmetry has been mentioned by other researchers, we explicitly relate it to various specific, structur... Read More about The influence of datacenter usage on symmetry in datacenter network design.

On the combinatorial design of data centre network topologies (2017)
Journal Article
Stewart, I. (2017). On the combinatorial design of data centre network topologies. Journal of Computer and System Sciences, 89, 328-348. https://doi.org/10.1016/j.jcss.2017.05.015

The theory of combinatorial designs has recently been used in order to build switch-centric data centre networks incorporating a large number of servers, in comparison with the popular Fat-Tree data centre network. We clarify and extend these results... Read More about On the combinatorial design of data centre network topologies.

Improved routing algorithms in the dual-port datacenter networks HCN and BCN (2017)
Journal Article
Erickson, A., Stewart, I., Pascual, J., & Navaridas, J. (2017). Improved routing algorithms in the dual-port datacenter networks HCN and BCN. Future Generation Computer Systems, 75, 58-71. https://doi.org/10.1016/j.future.2017.05.004

We present significantly improved one-to-one routing algorithms in the datacenter networks HCN and View the MathML source in that our routing algorithms result in much shorter paths when compared with existing routing algorithms. We also present a mu... Read More about Improved routing algorithms in the dual-port datacenter networks HCN and BCN.

The stellar transformation: from interconnection networks to datacenter networks (2016)
Journal Article
Erickson, A., Stewart, I., Navaridas, J., & Kiasari, A. (2017). The stellar transformation: from interconnection networks to datacenter networks. Computer Networks, 113, 29-45. https://doi.org/10.1016/j.comnet.2016.12.001

The first dual-port server-centric datacenter network, FiConn, was introduced in 2009 and there are several others now in existence; however, the pool of topologies to choose from remains small. We propose a new generic construction, the stellar tran... Read More about The stellar transformation: from interconnection networks to datacenter networks.

Sufficient conditions for Hamiltonicity in multiswapped networks (2016)
Journal Article
Stewart, I. (2016). Sufficient conditions for Hamiltonicity in multiswapped networks. Journal of Parallel and Distributed Computing, 101, 17-26. https://doi.org/10.1016/j.jpdc.2016.10.015

OTIS networks are interconnection networks amenable to deployment as hybrid networks containing both electronic and optical links. Deficiencies as regards symmetry led to the subsequent formulation of biswapped networks which were later generalized t... Read More about Sufficient conditions for Hamiltonicity in multiswapped networks.

An Optimal Single-Path Routing Algorithm in the Datacenter Network DPillar (2016)
Journal Article
Erickson, A., Kiasari, A., Navaridas, J., & Stewart, I. (2016). An Optimal Single-Path Routing Algorithm in the Datacenter Network DPillar. IEEE Transactions on Parallel and Distributed Systems, 28(3), 689-703. https://doi.org/10.1109/tpds.2016.2591011

DPillar has recently been proposed as a server-centric datacenter network and is combinatorially related to (but distinct from) the well-known wrapped butterfly network. We explain the relationship between DPillar and the wrapped butterfly network be... Read More about An Optimal Single-Path Routing Algorithm in the Datacenter Network DPillar.

Edge-pancyclicity and edge-bipancyclicity of faulty folded hypercubes (2016)
Journal Article
Kuo, C., & Stewart, I. (2016). Edge-pancyclicity and edge-bipancyclicity of faulty folded hypercubes. Theoretical Computer Science, 627, 102-106. https://doi.org/10.1016/j.tcs.2016.02.029

Let F v and Fe be sets of faulty vertices and faulty edges, respectively, in the folded hypercube FQn so that |F v | + |Fe | ≤ n − 2, for n ≥ 2. Choose any fault-free edge e. If n ≥ 3 then there is a fault-free cycle of length l in FQn containing e,... Read More about Edge-pancyclicity and edge-bipancyclicity of faulty folded hypercubes.

Routing packets on DPillar data centre networks (2015)
Presentation / Conference Contribution
Kiasari, A., Navaridas, J., & Stewart, I. (2015, December). Routing packets on DPillar data centre networks. Presented at 15th International Conference on Algorithms and Architectures for Parallel Processing, ICA3PP, Zhangjiajie, China

An efficient shortest path routing algorithm in the data centre network DPillar (2015)
Presentation / Conference Contribution
Erickson, A., Kiasari, A., Navaridas, J., & Stewart, I. (2015, December). An efficient shortest path routing algorithm in the data centre network DPillar. Presented at 9th Annual International Conference on Combinatorial Optimization and Applications, COCOA, Houston, USA

DPillar has recently been proposed as a server-centric data centre network and is combinatorially related to the well-known wrapped butterfly network. We explain the relationship between DPillar and the wrapped butterfly network before proving a symm... Read More about An efficient shortest path routing algorithm in the data centre network DPillar.

On the mathematics of data centre network topologies (2015)
Presentation / Conference Contribution
Stewart, I. (2015, August). On the mathematics of data centre network topologies. Presented at 20th International Symposium on Fundamentals of Computation Theory, Gdańsk, Poland

In a recent paper, combinatorial designs were used to construct switch-centric data centre networks that compare favourably with the ubiquitous (enhanced) fat-tree data centre networks in terms of the number of servers within (given a fixed server-to... Read More about On the mathematics of data centre network topologies.

Routing algorithms for recursively-defined data centre networks (2015)
Presentation / Conference Contribution
Erickson, A., Kiasari, A., Navaridas, J., & Stewart, I. (2015, December). Routing algorithms for recursively-defined data centre networks. Presented at 13th IEEE International Symposium on Parallel and Distributed Processing with Applications, Helsinki

The server-centric data centre network architecture can accommodate a wide variety of network topologies. Newly proposed topologies in this arena often require several rounds of analysis and experimentation in order that they might achieve their full... Read More about Routing algorithms for recursively-defined data centre networks.

Improved routing in the data centre networks HCN and BCN (2014)
Presentation / Conference Contribution
Stewart, I. (2014, December). Improved routing in the data centre networks HCN and BCN. Presented at 2nd International Symposium on Computing and Networking - Across Practical Development and Theoretical Research, Shizuoka, Japan