Design implementation and measurement of a collision avoidance multiple broadcast tree network

Packet collisions and their resolution create a performance bottleneck in random access LANs. Collision avoidance switches are a hardware solution to this problem [1, 2]. Collision avoidance switches allow the implementation of random access protocols without the penalty of collisions among packets.In this paper, we describe a design and implementation of a local area network architecture based on collision avoidance, called the Collision Avoidance Multiple Broadcast (CAMB) tree network. Our implementation follows the protocol layering architecture of the IEEE 802 local area networks, and includes CAMB tree switches, station/network interface boards, and support of transport protocols. We also present the performance measurements of our experimental CAMB tree network

A critical look at power law modelling of the Internet

This paper takes a critical look at the usefulness of power law models of the Internet. The twin focuses of the paper are Internet traffic and topology generation. The aim of the paper is twofold. Firstly it summarises the state of the art in power law modelling particularly giving attention to existing open research questions. Secondly it provides insight into the failings of such models and where progress needs to be made for power law research to feed through to actual improvements in network performance.Comment: To appear Computer Communication

Transition to High-Speed Networks — SuperJANET Experience

For the time being, trials to establish the Information Superhighway are booming. In Britain, JANET has provided wide-area computer communication, and has recently been upgraded to SuperJANET, increasing the throughput by a factor of five to 10 Mb/s, with some sites having PDH access at n × 34 Mb/s. In this paper, the technological changes seen from a user perspective are addressed. A multimedia communication-based distance learning project on SuperJANET is introduced and the network performance measurements for this project are presented. These measurements suggest the employment of reservation protocol and packet scheduling. We also provide a mechanism for on-the-fly playback of continuous media

An Energy and Performance Exploration of Network-on-Chip Architectures

In this paper, we explore the designs of a circuit-switched router, a wormhole router, a quality-of-service (QoS) supporting virtual channel router and a speculative virtual channel router and accurately evaluate the energy-performance tradeoffs they offer. Power results from the designs placed and routed in a 90-nm CMOS process show that all the architectures dissipate significant idle state power. The additional energy required to route a packet through the router is then shown to be dominated by the data path. This leads to the key result that, if this trend continues, the use of more elaborate control can be justified and will not be immediately limited by the energy budget. A performance analysis also shows that dynamic resource allocation leads to the lowest network latencies, while static allocation may be used to meet QoS goals. Combining the power and performance figures then allows an energy-latency product to be calculated to judge the efficiency of each of the networks. The speculative virtual channel router was shown to have a very similar efficiency to the wormhole router, while providing a better performance, supporting its use for general purpose designs. Finally, area metrics are also presented to allow a comparison of implementation costs

Development of a building information modelling (BIM) migration path model for construction professionals

The construction professionals have the notion that by implementing Building Information Modelling (BIM) in construction could overcome problems such as delay, cost overrun, clashes in project design and undesirable quality in construction. However, they failed to take the advantages of the BIM benefit as they are still trying to find the best way to take on board the BIM into current practices. Most of the professionals do not know ‘when’ and ‘how’ to apply BIM throughout the construction lifecycle. Several research models related to BIM has been developed to improve and encourage BIM implementation. Nevertheless, the developed models have limitations in highlighting the steps involved that could assist the construction professionals in implementing BIM effectively in Malaysia. Therefore, this research is aimed to develop a model that would be able to assist Malaysian construction professionals in implementing BIM in a structured way. A semi-structured interview was carried out with respondents that have various experienced and currently involved in BIM projects in the Malaysian construction industry. Findings show that the construction professionals are lacking in knowledge and experience in using BIM in various stages of construction. Thus, they were unable to fully capitalise the benefit of 3D models. Migration path model was proposed and evaluated as a strategic approach for BIM implementation in the Malaysian construction industry. The identification of five (5) activities (BIM Awareness, Develop BIM Strategy, Implement BIM, Monitor BIM and Expand BIM Implementation) with the three (3) enablers (BIM work contract, BIM work process and BIM technology) in the model is expected to be able to assist construction professionals to implement BIM with the right BIM concept and later, the benefit could be obtained for improving construction project. The proposed model could be as a guideline for construction professionals in implementing BIM, specifically in countries that new in BIM. The model is also expected to be able to fill the gap in BIM implementation by supporting the initiatives by the Malaysian government for increasing productivity in construction projects by using new technology like BIM