scispace - formally typeset
Search or ask a question
Author

Mahesh Sivakumar

Bio: Mahesh Sivakumar is an academic researcher from University of Maryland, College Park. The author has contributed to research in topics: Mesh networking & Network planning and design. The author has an hindex of 2, co-authored 2 publications receiving 10 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: The mechanism proposed to counter backup contention is seen to provide an average of 120% reduction in the contention among backup paths of connections traversing a link, especially when the number of wavelengths in each link is small.
Abstract: We consider the problem of survivable network design in traffic-groomed optical WDM mesh networks that support subwavelength capacity connections. In typical survivable network designs, individual sessions are provided either full protection or no protection. We consider a quality of protection (QoP) framework where a connection is provided partial protection, i.e., when a link failure occurs on the primary path, the protection bandwidth provided on the backup path is less than or equal to the primary bandwidth. Each connection request specifies the primary bandwidth and a minimum backup bandwidth required. The network will guarantee at least the minimum backup bandwidth and, if capacity is available, higher backup bandwidth up to the primary path's bandwidth. The advantage of such a model is that it can reduce backup capacity requirements based on connection needs leading to lower blocking probability and lower network costs. We consider two scenarios: (i) a network with static traffic that is designed using an integer linear program (ILP) formulation and (ii) a network with dynamic traffic for which we present a heuristic connection admission control algorithm that prevents backup resource contention during recovery from a link failure. The results quantify the gain in blocking probability for different partial protection scenarios. The mechanism proposed to counter backup contention is seen to provide an average of 120% reduction in the contention among backup paths of connections traversing a link, especially when the number of wavelengths in each link is small.

8 citations

Journal ArticleDOI
TL;DR: This work considers the problem of traffic grooming in optical wavelength division multiplexed (WDM) mesh networks under static traffic conditions and proposes a limited conversion-based grooming architecture for optical WDM mesh networks.
Abstract: In this article, we consider the problem of traffic grooming in optical wavelength division multiplexed (WDM) mesh networks under static traffic conditions. The objective of this work is to minimize the network cost and in particular, the electronic port costs incurred for meeting a given performance objective. In earlier work, we have shown the benefits of limited grooming switch architectures, where only a subset of wavelengths in a network are equipped with expensive SONET Add Drop Multiplexers (SADM) that provide the grooming functionality. In this work, we also consider the wavelength conversion capability of such groomers. This can be achieved using a digital cross-connect (DCS) in the grooming switch to switch low-speed connections between the SADMs (and hence, between wavelengths). The grooming switch thus avoids the need for expensive optical wavelength converters. Based on these observations, we propose a limited conversion-based grooming architecture for optical WDM mesh networks. The local ports at every node in this architecture can be one of three types: an add-drop port, a grooming port that allows wavelength conversion or a grooming port that does not allow wavelength conversion. The problem studied is: given a static traffic model, where should the different ports be placed in a network? We formulate this as an optimization problem using an Integer Linear Programing (ILP) and present numerical results for the same. We also present a heuristic-based approach to solve the problem for larger networks.

2 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: This work proposes a mixed-integer-linear-program (MILP) solution and a computationally efficient heuristic, and considers two partial-protection models to support degraded services in mixed-line-rate networks.
Abstract: Traffic in optical backbone networks is increasing and becoming more heterogeneous with respect to bandwidth and QoS requirements due to the popularity of high-bandwidth services (such as cloud computing, e-science, telemedicine, etc.), which need to coexist with traditional services (HTTP, etc.). Mixed-line-rate (MLR) networks that support lightpaths of different rates such as 10, 40, 100 Gb/s, etc., are being studied to better support the heterogeneous traffic demands. Here, we study the important topic of degraded services in MLR networks, where a service can accept some degradation (i.e., reduction) in bandwidth in case of a failure in exchange for a lower cost, a concept called partial protection. Network operators may wish to support degraded services to optimize network resources and reduce cost. We propose using multipath routing to support degraded services in MLR networks, a problem that has not been studied before and is significantly more challenging than in single-line-rate (SLR) networks. We consider minimum-cost MLR network design (i.e., choosing which transponder rates to use at each node), considering the opportunity to exploit multipath routes to support degraded services. We propose a mixed-integer-linear-program (MILP) solution and a computationally efficient heuristic, and consider two partial-protection models. Our illustrative numerical results show that significant cost savings can be achieved due to partial protection versus full protection and is highly beneficial for network operators. We also note that multipath routing in MLR networks exploits volume discount of higher-line-rate transponders by cost-effectively grooming requests over appropriate line rates to maximize transponder reuse versus SLR.

25 citations

Proceedings ArticleDOI
01 Dec 2011
TL;DR: A multipath routing scheme to support degraded services in MLR networks is developed, and illustrative examples show that significant cost savings can be achieved vs. full protection.
Abstract: Traffic in optical backbone networks is increasing and becoming heterogeneous with respect to bandwidth and QoS requirements due to the popularity of high-bandwidth services such as cloud computing, e-science, telemedicine, etc which need to coexist with traditional services (HTTP, etc) Mixed-line-rate (MLR) networks which support lightpaths of different rates are being studied to support the heterogeneous traffic demands Here, we study the important topic of degraded services in MLR networks, where a service can accept degradation in bandwidth to a certain extent in case of a failure for lower cost, a concept called partial protection Network operators may wish to support degraded services to optimize network resources and reduce cost We develop a multipath routing scheme to support degraded services in MLR networks, and our illustrative examples show that significant cost savings can be achieved vs full protection

6 citations

Proceedings ArticleDOI
20 Nov 2009
TL;DR: It is proposed that the main traffic types of today's applications should be carried using the following features: connection-oriented service, traffic grooming to fill those connection oriented pipes, and forward error recovery with protection provided in the physical layer.
Abstract: Today networks are too cumbersome due to the incoherent integration of various technologies developed over time. Convergence of data, voice, and video has caused the retro-fitting of a network to support non-native traffic types and this has led to sub-par performance for every traffic type. Fundamental changes are warranted to support high bandwidth traffic. The network must guarantee end-to-end delivery and provide inherent protection within the physical structure. We propose that the main traffic types of today's applications should be carried using the following features: connection-oriented service, traffic grooming to fill those connection oriented pipes, and forward error recovery with protection provided in the physical layer. We present some of our research results.

5 citations

Journal ArticleDOI
TL;DR: The proposed SPXP algorithm reduces the recovery time by ensuring that backup resources are pre‐configured along each backup segment and, hence, is readily available upon a failure.
Abstract: We propose a new approach for developing segment-based schemes for protection against single link/node failure in wavelength division multiplexing (WDM) mesh networks. In the proposed approach, every request is allocated a pair of link disjoint but most coupled primary and backup paths. Two paths are said to be most coupled if they share the maximum number of end nodes of some existing requests. Coupled paths reduce the total number of hops need to be traversed by a failure signal and, hence, potentially reduces the overall recovery time. We show that the problem of finding a pair of disjoint and most coupled paths is NP-complete. Accordingly, we propose an efficient and fast protection algorithm called SPXP—Segment Pre-Cross-Connected Protection, to allocate disjoint and most coupled paths. The proposed SPXP algorithm reduces the recovery time by ensuring that backup resources are pre-configured along each backup segment and, hence, is readily available upon a failure. Simulation results for different incremental traffic models and network topologies show that, for most cases, the proposed SPXP exhibits better performance in terms of blocking probability, resource usage, and recovery time compared with existing protection schemes. Copyright © 2010 John Wiley & Sons, Ltd.

3 citations

Proceedings ArticleDOI
02 Nov 2009
TL;DR: It is proposed that the main traffic types of today's applications should be carried using the following features: connection-oriented service, traffic grooming to fill those connection oriented pipes, and forward error recovery with protection provided in the physical layer.
Abstract: Internet services and applications require high reliability and different bandwidth that need to be supported over the high capacity wavelength channels. We will present a short overview of issues in design of wavelength division multiplexing, efficient protection, and access and grooming mechanisms to make the network transparent, scalable, reliable, and simple. Article not available.

3 citations