By taking advantage of statistical multiplexing in the burst level, Optical Burst Switching (OBS) technology enables
optical internet to handle huge volume of data in an efficient manner without requiring optical memories in the optical
domain. However, when the congestion is built in the optical network core, large amount of data can be lost. In this paper,
we propose an efficient burst control algorithm, which operates based on the awareness on future traffic condition.
Through the performance analysis, it is verified that the proposed algorithm effectively decreases the burst loss while
maintaining high throughput as compared to the burst control algorithm based on current information.
Optical Internet carries IP traffic over a WDM optical network by taking advantage of huge bandwidth of optical network. The optical burst switching (OBS) was proposed to enhance the low utilization problem of a wavelength routing (or optical circuit switching) and at the same time, relax the technical difficulty in implementing optical packet switching. The optical burst switched networks consists of the edge routers and the core routers. In particular, the edge routers perform the adaptation function, which interfaces between the electronic layer (IP, ATM, SONET) and the optical layer (OBS networks). One of the key functions of the edge router is the burst assembly, in which the data from the electronic layer assembled into a super packet (called a burst). In this paper, we compare three burst assembly schemes: constant assemble time (CAT), variable assemble time (VAT), and adaptive assemble time (AAT). The performance of burst assemble schemes are compared based on the extensive simulations.
The offset-time-based QoS scheme has been proposed for the next generation Optical Internet as a way to improve current IP's best effort service. For a single node, it has been shown that the offset-time-based scheme efficiently achieves service differentiation without requiring any buffer at the WDM layer. In this paper, the offset-time-based scheme is applied to the multi-hop base. To this end, we consider various policies to handle blocked bursts such as drop, retransmission, deflection routing and buffering in the multi-hop very high performance Backbone Network Service (vBNS), and compare their performance in terms of average wavelength utilization, the average wavelength efficiency and the average end-to-end extra delay. It is shown that the buffering policy is useful with scarce network resource (e.g., bandwidth), but the dropping policy in conjunction with the offset-time-based scheme is good enough with abundant resources.
Optical burst switching (OBS) is a new paradigm proposed to efficiently support the ever-growing broadband multimedia traffic either directly or indirectly (e.g., via IP) over all optical WDM networks. In this paper, we propose a new prioritized OBS protocol based on Just-Enough-Time which can provide Quality of Service in buffer-less WDM optical networks. Specifically, we apply OBS to support two traffic classes: real-time and non-real-time, such that each burst belonging to the former is assigned a higher priority by simply using an additional offset time between the burst and its corresponding control (set-up) packet. We analyze the lower and upper bounds on the blocking probability of each traffic class, and evaluate the performance of the proposed prioritized OBS protocol through analysis and simulation. We show that real-time traffic can achieve a significantly reduced blocking probability by using a reasonable amount of additional offset time. In addition, the overall blocking probability and throughput can be maintained regardless of the additional offset time used.
An optical backbone network based on WDM (or OTDM) technology may become an economical choice for providing future broadband services. To achieve a balance between the coarse-grain optical circuit switching (via wavelength routing) and fine- grain optical packet/cell switching, optical burst switching is proposed. We study a one-way reservation protocol called just-enough-time (JET), which is suitable for switching bursty traffic in a high speed optical backbone network. The JET protocol has two unique, integrated features, namely, the use of delayed reservation (DR) and buffered burst multiplexers (BBM). By virtue of DR, the JET protocol not only increases the bandwidth utilization, but also facilitates intelligent buffer management in BBMs, and consequently results in a high through-put. Both analysis and simulation results show that the JET protocol can significantly outperform other one-way reservation protocols lacking one or both of these features.
Conference Committee Involvement (1)
Network Architecture, Management, and Applications IV
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