Performance analysis of asynchronous best-effort traffic coexisting with TDM reservations in polymorphous OBS networks (original) (raw)

Performance analysis of an optical burst switching (OBS) network

2008 International Conference on Electrical and Computer Engineering, 2008

The development of wavelength division multiplexing opens a new horizon in optical networks and promises to be one of the best solutions for the high demand of the bandwidth. However, with this technology, many problems arise, especially those related to the architecture to be used in optical networks to take advantage of the huge potential of this technique. Many approaches and architectures have been proposed in literatures to carry information in optical domain. Among them, optical burst switching (OBS) and wavelength routed network seems to be the most successful. We propose a new novel architecture that uses both methods in order to overcome the limitations imposed by each approach. The proposed architecture deploys bursty traffic in a hybrid fashion where implicitly predicted and explicitly pre-booked traffic are dynamically allocated reserved end-to-end paths, inheriting the spirit of conventional wavelength routing; whilst, the non-predicted traffic is transmitted via classical OBS reservation mechanism(s) with the best efforts support. The complete network structure alongwith load-balancing prior reservation strategy is presented. Simulation results reveal the performance of the proposed work by examining the blocking probability and delay characteristics. The encouraging results provide stimulation for further work on optimal traffic placement, QoS provisioning, and various apriori resource reservation strategies.

Performance Evaluation and Design of Polymorphous OBS Networks With Guaranteed TDM Services

Journal of Lightwave Technology, 2000

In Polymorphous Optical Burst-Switched (POBS) networks, the Burst Control Packets (BCPs) of conventional Just-Enough-Time based signalling OBS networks are given extended properties which enable them not only to reserve fixed time-slots for asynchronous data bursts, but also to allocate TDM reservations for periodic streams of data, and even a complete wavelength for high-bandwidth demanding services. This allows POBS to provide a flexible, yet transparent, approach for supporting the idiosyncrasies of today's most popular services over the same underlying network architecture. In POBS, the spare gaps in between synchronous TDM reservations can be used for the allocation of best-effort data bursts, leading to a more efficient utilisation of the optical capacity.

Analysis and design of optical burst switching networks

2005

Optical Burst Switching (OBS) is a hybrid technique between coarse grain optical circuit switching and fine grain optical packet switching. In OBS networks, user data is switched entirely in the optical domain, while control and management functions are performed in the electrical domain. This separation of the data plane and the control plane allows OBS networks to provide reasonably high levels of utilization while circumventing the need for optical buffering. In spite of OBS favorable features, several issues need to be addressed before OBS can be deployed in the Internet backbone. The objectives of this thesis are twofold: devise new methods for quality-of-service (QoS) provisioning in OBS networks, and develop new wavelength scheduling algorithms for enhancing the blocking probability in OBS networks. QoS provisioning is a major research problem in OBS networks. This is mainly because of the absence of the concept of "packet queues" in OBS networks. This thesis proposes two approaches for QoS provisioning in OBS networks. The first approach is a simple, yet effective scheme, called preemptive prioritized just enough time (PPJET). PP JET provides better service for high priority traffic by dropping reservations belonging to lower priority traffic using a new channel scheduling algorithm called preemptive latest Abstract in available unused channel with void filling (PLAUC-VF). Simulation results show that PPJET outperforms offset-based QoS schemes both in terms of dropping probability and end-to-end delay. As a second approach for solving the QoS problem in OBS networks, we present a detailed architecture for providing quantitative QoS guarantees with respect to endto-end delay, throughput, and packet loss probability in labeled OBS networks. The architecture describes a novel approach for applying fair scheduling algorithms in both the data plane of labeled OBS edge nodes and the control plane of core nodes without the need for optical buffering. In addition, we present analytical results for delay, throughput, and blocking probability in the proposed architecture. Simulation results demonstrate that the proposed architecture provides accurate and controllable service differentiation in labeled OBS networks. The absence of optical buffers in OBS nodes, coupled with the one way nature of OBS signaling protocols, drives the blocking probability to become the main performance measure in OBS networks. This give rise to the need for analytical models for calculating the blocking probability in OBS networks. In this thesis we present an approximate analytical model for calculating the blocking probability in OBS networks. The proposed analytical model takes into consideration the peculiar characteristics of OBS networks. To verify its accuracy, we compared the model results with results from a discrete-event simulation model. The proposed model results are in satisfactory agreement with simulation results.

Hybrid Resource Reservation Mechanism for Optical Burst Switched Networks

This paper proposes a novel hybrid resource reservation mechanism that can operate with existing Optical Burst Switching (OBS) architectures, providing an efficient infrastructure for multi-service "bandwidth on demand" transport. It proposes deploying bursty traffic in a hybrid fashion where implicitly predicted and explicitly pre-booked traffic are dynamically allocated reserved end-to-end paths, inheriting the spirit of conventional wavelength routing; whilst, the non-predicted traffic is transmitted via classical OBS reservation mechanism(s) with the best efforts support. The complete network structure is presented and an explicit coarse-interval load-balancing prior reservation strategy is also described in detail. Simulation results reveal the performance of the proposed work by examining the blocking probability, end-to-end delay, and the wavelength deployment characteristics. The encouraging results should provide stimulation for further work on optimal traffic pla...

OPS or OBS in the Core Network? -A Comparison of Optical Packet-and Optical Burst Switching

Optical Packet Switching (OPS) and Optical Burst Switching (OBS) are optically switched networks architectures aiming to serve higher layer packetbased communication protocols. This paper gives a rationale for introducing these switching schemes in telecommunication networks, and discusses transparency and channel count in the context of contention resolution. Focusing on asynchronous operation with variable length optical packets/bursts, we review the latest work on OPS and OBS designs, contention resolution methods and OBS reservation mechanisms. The performance of both OPS and OBS is reviewed and held up against design complexity.

Efficient resource reservation for optical burst switching networks

2009 IEEE Global Telecommunications Conference, GLOBECOM 2009

Optical burst switching (OBS) is one promising method for data transfer in photonic networks based on a WDM (Wavelength Division Multiplexing) technology. In the OBS scheme, the wavelength is exclusively reserved along the source and destination nodes, when the burst data is generated at the source. Then, efficient data transfer is expected. However, its performance is heavily dependent on the number of links that the lightpath goes through. TCP-based applications account for a majority of data traffic in the Internet; thus understanding and improving the performance of TCP over OBS networks is critical. In this paper, we present a new parallel wavelength reservation method for optical burst switching (OBS) networks based on adapting the set of potential wavelengths with the number of hops in the path. The uniqueness of this work when compared to existing works is that buffering resources, which consist of Optical Delay Lines (ODLs), are considered in the reservation mechanism. The consequence of this is that the time made by the segments in the various buffers across the selected path is taken into consideration. Various simulation experiments have been conducted to evaluate the performance of the scheme. It is found that our approach has better performance than previous related works reported in the literature. http://ieeexplore.ieee.org/xpls/abs\_all.jsp?arnumber=5425688

Performance analysis of the Sent-But-Sure strategy for Optical Burst and Packet Switched Networks

Performance Evaluation, 2011

This work proposes an analytical model to characterize the performance of a loss-free transmission strategy for Optical Burst and Packet Switched Networks, which ensures that a burst/packet will successfully reach its destination once it has been scheduled in the first link of its path. In this paper this strategy is called Sent-But-Sure (SBS) because it avoids losses in any intermediate node. The SBS strategy combines a routing and wavelength assignment scheme with simple contention resolution mechanisms. As a result, new burst/packet allocation attempts in an intermediate node only contend with bursts/packets in transit coming from a single input link. Moreover, bursts/packets in transit always have priority over bursts/packets whose transmission has not been scheduled yet. These two main features of the SBS strategy allow us to develop an analytical model based on a twopriority M/G/1 queueing model to characterize the network performance. A. Agustí et al. / Performance Evaluation 68 (2011) 1-20 service requirements, and the deployment of new services, is increasing the need for developing more efficient switching techniques at the sub-wavelength granularity.

Burst-Switched Optical Networks Supporting Legacy and Future Service Types

2011

Focusing on the principles and the paradigm of OBS an overview addressing expectable performance and application issues is presented. Proposals on OBS were published over a decade and the presented techniques spread into many directions. The paper comprises discussions of several challenges that OBS meets, in order to compile the big picture. The OBS principle is presented unrestricted to individual proposals and trends. Merits are openly discussed, considering basic teletraffic theory and common traffic characterisation. A more generic OBS paradigm than usual is impartially discussed and found capable to overcome shortcomings of recent proposals. In conclusion, an OBS that offers different connection types may support most client demands within a sole optical network layer.

The use of a triangular estimator to improve scheduling in optical burst switched networks

International Journal of Communication Systems, 2010

In an optical burst switched network, variable-sized data bursts are switched on the fly using bandwidth previously reserved by their control packets. A key problem in OBS networks is the assignment of wavelengths to incoming bursts, that is, the scheduling of bursts. This paper proposes a new class of burst scheduling algorithms based on a triangular estimator. The proposed tool reduces the complexity of the scheduling scheme (measured in channel checks) without compromising its performance (measured by the burst drop ratio). Simulation results demonstrate both the accuracy and the efficiency of the estimator in a variety of scenarios and under self-similar network traffic. Figure 1. A general architecture of an OBS network.

Analysis of blocking probability in optical burst switched networks

Photonic Network Communications, 2008

In this article, we study the blocking probability in a wavelength division multiplexing (WDM) based asynchronous bufferless optical burst switched (OBS) network, equipped with a bank of wavelength converters. Our analysis encloses two wavelength reservation schemes JIT (just-intime) and JET (just-enough-time), and two-class data rate. The contribution of our work includes: (i) derivation of an accurate model for blocking probability of lower priority bursts in case of a non-preempted model; (ii) provision of the analytical model for blocking probability calculation in the OBS network, which includes these variables: two signaling schemes, partial wavelength conversion, two-class data, traffic intensity, cross-connect speed, number of wavelengths in WDM fiber, number of fibers in the node, number of wavelength converters, and number of nodes in the path; (iii) simulation results, which show that partial wavelength conversion provide quite satisfactory quality of service. We compare performance in a single OBS node, under various sets of parameter values. The OBS network shows great flexibility in terms of used multiclass data, and there is no dependence on the used higher layer protocol.