Comparative Study Of Offset Time Schemes Over Optical Burst Switching (OBS)

Abstract

Penggunaan internet yang meluas dan berterusana menyebabkan kenaikan trafik dalam talian. Teknik Optical Burst Switching (OBS) boleh dikatakan sebagai penyelesaian kepada masalah trafik di dalam rangkaian internet. Namun demikian, terdapat beberapa isu dalam rangkaian OBS. Salah satu isunya adalah untuk meminimakan offset masa tunda dan untuk mengatasi masalah ini, terdapat banyak penyelidikan dilakukan menggunakan berbagai cara dan teknik. Laporan ini menyediakan penerangan mengenai skema yang telah digunakan disamping menghuraikan mengenai kelebihan dan kekurangan skema yang telah sedia ada. Kata kunci: OBS; offset time The dramatic and continuous use of the Internet has increased the network traffic that is needed to be transferred through the Internet network. Optical Burst Switching (OBS) has met the requirements of such demands and is considered as a solution of the issues present in Internet networks. However, there are still some issues in OBS network have not been solved. Minimizing offset time delay is one of these concerns and a lot of research has been introduced in order to solve this issue through using various ways or schemes. In this paper, a description of these schemes and their advantages and disadvantages is presented. Key words: OBS; offset time

Hybrid offset‐time and burst assembly algorithm (H‐OTBA) for delay sensitive applications over optical burst switching networks

“…In some of these schemes, loss rate is highly affected. Fixed offset-time scheme comes from OBS protocol Just-Enough-Time [3,21]. In this protocol, offset-time is fixed and equals the sum of the total processing time of all the intermediate OBS hops, the switch fabric configuration time of the egress OBS node.…”

“…Extra offset-time is assigned to bigger burst in order to get a high isolation degree among bursts that have different sizes in adaptive offset-time scheme [21,22]. Also, an isolation degree of 1 can be achieved if the offset-time differentiation equals the burst size.…”

“…The offset-time is reduced by forwarding the control packet that contains estimation for the burst length before the burst assembly period ends [21,23]. This method is effective because it does not cause extra offset-time delay and the transmission of the burst is achieved more quickly than the conventional method.…”