Mike J. O'Mahony

Bio: Mike J. O'Mahony is an academic researcher from University of Essex. The author has contributed to research in topics: Packet switching & Optical burst switching. The author has an hindex of 21, co-authored 83 publications receiving 2400 citations.

Transmission impairments in WDM networks

Abstract: Summary form only given. In recent years there has been increased activity in studying the application of WDM techniques to networking in addition to straight point-to-point systems. In particular, attention has been paid to optical transport and access networking, using modeling and experiment to understand the benefits of such approaches. Optical networks have different and more complex characteristics than point-to-point systems and hence understanding the transmission limitations associated with such networks requires more complex modeling. The network end-to-end performance is a function of many variables, which may have different statistical properties, and is also dependent on the size and topology of the network. Examples of major network related issues are given: crosstalk; amplifier gain flatness and equalization; wavelength converter impairment; active switches; filter cascades and stability; gated amplifiers.

Designing a High Speed Optical Packet Switched Network

Abstract: Optical packet switching is foreseen as a future-proof technology for next generation optical networks, as it provides a solution for more efficient bandwidth utilization. Design issues concerning technological and architectural approaches for the deployment of optical packet switching in high-speed networks are examined. First the two different types of packet routers for the edge and the core are identified and the required elements are presented. Then issues concerning the header encoding extraction and switch control are discussed. Finally, a fast optical packet switch that can route asynchronous data traffic with variable length packets at 40 Gb/s is presented. The developed techniques for the header extraction scheme, the advanced control mechanism and the bit rate transparent and widely tunable wavelength conversion scheme are shown in detail. Keywords: Optical packet switched networks, optoelectronic design, wave mixing, DPSK header decoding.

An All-Optical Time-Slot Interchange Architecture

Abstract: A novel, bit-rate scaleable and transparent Time-Slot Interchange architecture is proposed and experimental results demonstrate error-free performance at 40Gbit/s. The proposed architecture can be used in an OTDM-based optical cross-connect node.

An efficient and fully-scalable architecture applied to bufferless photonic nodes with DiffServ

Abstract: A general-purpose multistage architecture to simultaneously tackle component count and scalability is proposed. Manufacturing, maintenance, and reliability are also benefited by its modular structure. Crosspoints saving is analysed. A three-step switch upgrade under prioritised traffic is briefly discussed.

Optical burst switching (OBS) - a new paradigm for an optical Internet

Abstract: To support bursty traffic on the Internet (and especially WWW) efficiently, optical burst switching (OBS) is proposed as a way to streamline both protocols and hardware in building the future gener...

On Global Electricity Usage of Communication Technology: Trends to 2030

Abstract: This work presents an estimation of the global electricity usage that can be ascribed to Communication Technology (CT) between 2010 and 2030. The scope is three scenarios for use and production of consumer devices, communication networks and data centers. Three different scenarios, best, expected, and worst, are set up, which include annual numbers of sold devices, data traffic and electricity intensities/efficiencies. The most significant trend, regardless of scenario, is that the proportion of use-stage electricity by consumer devices will decrease and will be transferred to the networks and data centers. Still, it seems like wireless access networks will not be the main driver for electricity use. The analysis shows that for the worst-case scenario, CT could use as much as 51% of global electricity in 2030. This will happen if not enough improvement in electricity efficiency of wireless access networks and fixed access networks/data centers is possible. However, until 2030, globally-generated renewable electricity is likely to exceed the electricity demand of all networks and data centers. Nevertheless, the present investigation suggests, for the worst-case scenario, that CT electricity usage could contribute up to 23% of the globally released greenhouse gas emissions in 2030.

Advances in photonic packet switching: an overview

Abstract: The current fast-growing Internet traffic is demanding more and more network capacity every day. The concept of wavelength-division multiplexing has provided us an opportunity to multiply network capacity. Current optical switching technologies allow us to rapidly deliver the enormous bandwidth of WDM networks. Photonic packet switching offers high-speed, data rate/format transparency, and configurability, which are some of the important characteristics needed in future networks supporting different forms of data. In this article we present some of the critical issues involved in designing and implementing all-optical packet-switched networks.