IJEEE, Vol. 1, Issue 6 (December, 2014)
e-ISSN: 1694-2310 | p-ISSN: 1694-2426
PERFORMANCE EVALUATION AND OPTIMIZATION OF BLOCKING PROBABILITY IN PASSIVE OPTICAL BURST SWITCHING NETWORK 1 1,2 1
Bharti Tagra, 2Sukhvinder Kaur, 3Dr. Amit Wason
Swami Devi Dyal Institute of Engineering and Technology, Haryana, India 3 Ambala College of Engineering & Applied Research, Haryana, India
tagra.bharti@gmail.com,
2
er1971sukhvinderkaur@rediffmail.com,
Abstract- The generalized Engset model can be applied to evaluate the blocking probability in the Passive Optical Burst Switching Network. We provide a wide range of simulation and numerical results to validate our method and demonstrate various effects on Blocking Probability such as Number of Wavelength, Round Trip Delay and Mean Packet interarrival Time. Keyword- Optical Network, Passive Optical Network, Optical Burst Switching Network, Engset Model, Blocking Probability. I. INTRODUCTION All-Optical Networks are seen as a way to accommodate the continued exponential growth in Internet Traffic. For all-optical networks to be feasible, they must be both stable and sufficient [2]. A Passive Optical Network is a single, shared optical fiber that uses inexpensive optical splitters to divide the single fiber into separate strands feeding individual subscribers. Optical Networks are called “passive� because other than at the CO and subscriber endpoints, there are no active electronics within the access network. A Passive Optical Network includes an optical line terminal (OLT) and an optical network unit (ONU). The OLT resides in the CO (POP or local exchange). This would typically be an Ethernet switch or Media Converter platform. The ONU resides at or near the customer premise. It can be located at the subscriber residence, in a building, or on the curb outside. The ONU typically has an 802.3ah WAN interface, and an 802.3 subscriber interface. Passive Optical Networks is configured in full duplex mode (no CSMA/CD) in a single fiber point-to-multipoint (P2MP) topology [1]. Optical Burst Switching (OBS) is a technology that facilitates one-way dynamic resource reservation of data flows suited to all-optical networks. In OBS networks, data packets with the same destination are aggregated at ingress node and form bursts. A control packet is sent ahead of a burst to reserve a wavelength channels along the burst transmission path. Since the wavelength channels are reserved hop by hop, the reservation time ahead of data transmission is shorter than in an end-to-end reservation scheme used in optical circuit switching (OCS). Another benefit of OBS over OCS is that an OBS lightpath is fully utilized during a burst transmission. OBS is also compared to OCS and optical flow switching (OFS), where end-towww.ijeee-apm.com
3
wasonamit13@gmail.com
end network resources are reserved in advance, so that payload sent always reaches its destination. In OBS, a burst may be blocked and dumped after utilizing some network resources [6]. Performance studies of OBS networks have focused on Blocking Probability defined as the ratio of the bursts that are lost to the bursts that are sent and utilization [6]. This paper is organized in three sections. Introduction on Optical Network, Passive Optical Network and OBS Network is presented in section I. Section II describes the overview of related work done regarding Optical Burst Switching Network and its related research papers. Section III describes the Proposed Model. Finally Results and conclusion is given in section IV and V. II. LITERATURE REVIEW Jayant Baligaet. al [2], developed a new analytical model for the estimation of blocking probabilities in OPS and OBS networks which was used to analyze the performance of a new deflection method and gives network designers greater control over the performance of the network and demonstrated that multiple link reservation thresholds give network designers more control over network performance. Eric W.M. Wong et. al [3] considered an optical hybrid switch that can function as an optical burst switch and/or optical circuit switch and proposed and described a new implementation whereby circuits have non-preemptive priority over bursts. Also presented an analysis based on a 3-D Markov chain that provided exact results for the blocking probabilities of bursts and circuits, the proportion of circuits that were delayed and the mean delay of the circuits that were delayed. Extensive numerical results had demonstrated the accuracy of the approximations. Eric W.M. Wong et. al [4] proposed a new state dependent approximation for a special case of the generalized Engset model that considers packet/burst dumping and demonstrated that the new approximation was accurate. VyacheslavAbramovet. al [5] proposed to use an asymptotic approximation A-EFPA where the EFPA solution was unattainable, for the blocking probability and demonstrated savings of many orders of magnitudes in computation time for blocking probability approximation in realistically sized networks with large number of circuits per link and also demonstrated for NSFNet and internet2 accurate calculations of the blocking probability using simulations, EFPA and A-EFPA, where each of these three International Journal of Electrical & Electronics Engineering 5