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M.H.M. Nizam

Bio: M.H.M. Nizam is an academic researcher from University of Strathclyde. The author has contributed to research in topics: Network packet & Wavelength-division multiplexing. The author has an hindex of 3, co-authored 6 publications receiving 392 citations.

Papers
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Journal ArticleDOI
TL;DR: A photonic packet switching testbed is detailed which will allow the ideas developed within WASPNET to be tested in practice, permitting the practical problems of their implementation to be determined.
Abstract: WASPNET is an EPSRC-funded collaboration between three British Universities: the University of Strathclyde, Essex University, and Bristol University, supported by a number of industrial institutions. The project which is investigating a novel packet-based optical WDM transport network-involves determining the management, systems, and devices ramifications of a new network control scheme, SCWP, which is flexible and simplifies optical hardware requirements. The principal objective of the project is to understand the advantages and potential of optical packet switching compared to the conventional electronic approach. Several schemes for packet header implementation are described, using subcarrier multiplexing, separate wave lengths, and serial transmission. A novel node design is introduced, based on wavelength router devices, which reduce loss, hence reducing booster amplifier gain and concomitant ASE noise. The fabrication of these devices, and also wavelength converters, are described. A photonic packet switching testbed is detailed which will allow the ideas developed within WASPNET to be tested in practice, permitting the practical problems of their implementation to be determined.

294 citations

Journal ArticleDOI
TL;DR: In this article, a performance comparison between coherent optical code-division multiple access (OCDMA) and OTDMA systems is carried out, both of them using narrow-pulse laser sources.
Abstract: As the wavelength resource in mainstream wavelength-division multiple-access (WDMA) systems becomes exhausted, and the bit-rate limitation within a single wavelength bandwidth is reached, alternative approaches to implementing a high-capacity optical fiber network need to be investigated. Coherent optical code-division multiple-access (OCDMA) systems, that can access many users simultaneously and asynchronously (or synchronously) across the single wavelength and same timeslot via spread spectrum techniques, are one alternative. In the longer term, the advantages of OCDMA in tandem with WDMA (OCDMA/WDMA) networks are compelling and worthy of further investigation in the goal of realising an extensive, flexible, high throughput and easily managed optical telecommunication infrastructure. In this paper, coherent OCDMA systems are introduced, and the issues of the system implementation within high-capacity optical fiber networks are discussed. A performance comparison between OCDMA and OTDMA systems is then carried out, both of them using narrow pulse laser sources. An optical fiber network utilizing coherent OCDMA techniques as one layer of a multiplexing hierarchy, in tandem with WDMA, is illustrated and a possible hybrid OCDMA/WDMA network architecture (and its performances and advantages) is described.

90 citations

Proceedings ArticleDOI
17 Jun 1998
TL;DR: WASPNET as mentioned in this paper is an EPSRC-funded collaboration between Strathclyde, Essex, and Bristol Universities, with the aim of designing a flexible packet-based transport network.
Abstract: WASPNET is an EPSRC-funded collaboration between Strathclyde, Essex, and Bristol Universities, with the aim of designing a flexible packet-based transport network. It supports both conventional optical paths for the transport of SDH and also switches optical packets, thus providing a smooth upgrade path from SDH over WDM while still supporting legacy SDH equipment. A key feature of this network is the use of multiple wavelengths to help resolve packet contention and hence reduce the size of optical buffers that are required. This is advantageous since large optical buffers will be expensive and difficult to build. This paper describes some of the developments in WASPNET. Two possible control architectures have been studied, namely scattered wavelength path (SCWP) and shared wavelength path (SHWP). SCWP is the most suitable as it can distribute the load more efficiently and it requires a lower buffer size. Two possible node designs are then addressed; one based on feedback delays and one on feed forward delays, followed by a description of the sub-system components and their advantages and limitations. Finally the decoding of subcarrier modulated headers is covered. (6 pages)

7 citations

Proceedings ArticleDOI
07 Oct 1998
TL;DR: In this article, the authors describe the development of an optical packet transport network, known as WAvelength Switched Photonic NETwork (WASPNET), a collaboration between Strathclyde, Essex and Bristol Universities as well as BT, Fujitsu and GPT.
Abstract: This paper describes the development of an optical packet transport network, known as WAvelength Switched Photonic NETwork (WASPNET)--a collaboration between Strathclyde, Essex and Bristol Universities as well as BT, Fujitsu and GPT. One of its main objectives is to reduce packet contention at each node. Normally, this is resolved using node deflection routing or optical delay loops (i.e. the solution is focused at the node design strategy). However in WASPNET, this problem is considered not only as a node design problem but also as a network control and management issue. Although suitable node design can reduce packet loss performance, an appropriate network control can reduce the probability of contentions, hence, improve the network throughput and node cost. This suggests that the network management strategy also influences the node design. A possible network control methodology, the SCattered- Wavelength-Path (SCWP), has been identified to support WASPNET implementation. The paper presents some of the comparison studies that were carried out. These include comparing its limitations, control complexity, packet loss performance and buffer requirements against another technique--the Shared-Wavelength-Path. It highlights solutions to problems encountered by the SCWP. Although the studies performed were intended for WASPNET transport system, the findings are invaluable for those involved in WDM network design.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: Some of the critical issues involved in designing and implementing all-optical packet-switched networks are presented.
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.

637 citations

Journal ArticleDOI
TL;DR: In this article, advanced optical burst switching (OBS) and optical packet switching (OPS) technologies and their roles in the future photonic Internet are discussed and discussed in detail.
Abstract: This paper reviews advanced optical burst switching (OBS) and optical packet switching (OPS) technologies and discusses their roles in the future photonic Internet. Discussions include optoelectronic and optical systems technologies as well as systems integration into viable network elements (OBS and OPS routers). Optical label switching (OLS) offers a unified multiple-service platform with effective and agile utilization of the available optical bandwidth in support of voice, data, and multimedia services on the Internet Protocol. In particular, OLS routers with wavelength routing switching fabrics and parallel optical labeling allow forwarding of asynchronously arriving variable-length packets, bursts, and circuits. By exploiting contention resolution in wavelength, time, and space domains, the OLS routers can achieve high throughput without resorting to a store-and-forward method associated with large buffer requirements. Testbed demonstrations employing OLS edge routers show high-performance networking in support of multimedia and data communications applications over the photonic Internet with optical packets and bursts switched directly at the optical layer

509 citations

Journal ArticleDOI
TL;DR: This article focuses on the concept of an optical packet router as an edge network device, functioning as an interface between the electronic and optical domains, that may provide greater flexibility and efficiency than an electronic terabit router with reduced cost.
Abstract: Telecommunication networks are experiencing a dramatic increase in demand for capacity, much of it related to the exponential takeup of the Internet and associated services. To support this demand economically, transport networks are evolving to provide a reconfigurable optical layer which, with optical cross-connects, will realize a high-bandwidth flexible core. As well as providing large capacity, this new layer will be required to support new services such as rapid provisioning of an end-to-end connection under customer control. The first phase of network evolution, therefore, will provide a circuit-switched optical layer characterized by high capacity and fast circuit provisioning. In the longer term, it is currently envisaged that the bandwidth efficiency associated with optical packet switching (a transport technology that matches the bursty nature of multimedia traffic) will be required to ensure economic use of network resources. This article considers possible network application scenarios for optical packet switching. In particular, it focuses on the concept of an optical packet router as an edge network device, functioning as an interface between the electronic and optical domains. In this application it can provide a scalable and efficient IP traffic aggregator that may provide greater flexibility and efficiency than an electronic terabit router with reduced cost. The discussion considers the main technical issues relating to the concept and its implementation.

447 citations

Journal ArticleDOI
TL;DR: A survey of two new technologies which are still in the experimental stage-optical packet switching and optical burst switching-and comment on their suitability for transporting IP traffic.
Abstract: Wavelength-division multiplexing appears to be the solution of choice for providing a faster networking infrastructure that can meet the explosive growth of the Internet. Several different technologies have been developed so far for the transfer of data over WDM. We survey two new technologies which are still in the experimental stage-optical packet switching and optical burst switching-and comment on their suitability for transporting IP traffic.

413 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a comprehensive study of contention resolution schemes in a multi-wavelength optical packet-switched network, which include contention resolution in wavelength, time, and space dimensions.
Abstract: This paper presents a comprehensive study of contention-resolution schemes in a multiwavelength optical packet-switched network. This investigation aims to provide a unified study of a network of optical routers, which include contention resolution in wavelength, time, and space dimensions. Specifically, we show: 1) how to accommodate all three dimensions of contention resolution in an integrated optical router; 2) how the performance of the three dimensions compare with one another; and 3) how various combinational schemes can be designed and how they perform. With the representative architectures and network topologies studied in this paper, the simulation experiment results capture the characteristics of different contention-resolution schemes, and they quantify the upper-bound average offered transmitter load for these schemes. The combinational contention resolution schemes are shown to effectively resolve packet contention and achieve good network performance under light to intermediate load.

325 citations