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Journal ArticleDOI

Design and analysis of partial protection mechanisms in groomed optical WDM mesh networks

01 Jun 2008-Journal of Optical Networking (Optical Society of America)-Vol. 7, Iss: 6, pp 617-634
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.
Citations
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Book ChapterDOI
01 Jan 2012
TL;DR: This chapter provides upper bounds on how much primary capacity a network can provide if it uses a link based protection strategy to guarantee survivability for one or more link failures.
Abstract: Achieving low blocking probability and connection restorability in the presence of a link failure is a major goal of network designers. Typically fault tolerant schemes try to maintain low blocking probability by maximizing the amount of primary capacity in the network. In this chapter, we assume the total capacity on each link is fixed, and then it is allocated into primary or backup capacity. The distribution of primary capacity affects blocking probability for dynamic traffic. This can be seen by simulating dynamic traffic with different ways to distribute capacities in a network. A Hamiltonian p-cycle is a capacity optimal way of allocating primary and backup capacity. However, different Hamiltonian p-cycle may deliver different blocking probability for dynamic traffic. In general, more evenly distributing the backup and primary capacity lowers the blocking probability. This chapter provides upper bounds on how much primary capacity a network can provide if it uses a link based protection strategy to guarantee survivability for one or more link failures. Using integer linear programs we show that requiring preconfiguring carries a cost in terms of capacity if the solution is structured as a set of cycles. DOI: 10.4018/978-1-61350-426-0.ch007

2 citations

01 Jan 2012
TL;DR: This dissertation proposes robust architectures, capacity migration strategies, and novel service frameworks for next-generation hybrid circuit/packet architectures, and investigates techniques to dynamically migrate capacity between the circuit and packet sections by exploiting traffic variations over a day.
Abstract: Internet traffic is increasing rapidly at an annual growth rate of 35% with aggregate traffic exceeding several Exabyte’s per month. The traffic is also becoming heterogeneous in bandwidth and quality-of-service (QoS) requirements with growing popularity of cloud computing, videoon-demand (VoD), e-science, etc. Hybrid circuit/packet networks which can jointly support circuit and packet services along with the adoption of high-bit-rate transmission systems form an attractive solution to address the traffic growth. 10 Gbps and 40 Gbps transmission systems are widely deployed in telecom backbone networks such as Comcast, AT&T, etc., and network operators are considering migration to 100 Gbps and beyond. This dissertation proposes robust architectures, capacity migration strategies, and novel service frameworks for next-generation hybrid circuit/packet architectures. In this dissertation, we study two types of hybrid circuit/packet networks: a) IP-over-WDM networks, in which the packet (IP) network is overlaid on top of the circuit (optical WDM) network and b) Hybrid networks in which the circuit and packet networks are deployed side by side such as US DoE’s ESnet. We investigate techniques to dynamically migrate capacity between the circuit and packet sections by exploiting traffic variations over a day, and our methods show that significant bandwidth savings can be obtained with improved reliability of
Journal ArticleDOI
TL;DR: Simulation results show that the proposed schemes could well provide differentiated reliability with PSRLG constraint and achieve a good balance between reliability and resource efficiency without sacrificing reliability compared to the ICSR scheme.
Abstract: A multilink failures model, i.e., probabilistic-shared risk link group (PSRLG), is adopted to investigate the problem of differentiated quality-of-protection (QoP) provisioning for flexi-grid optical networks. As a metric, service failure probability (SFP) is introduced to exactly examine the feasibility of differentiated QoP schemes, which denotes the failure probability of a connection during transmission. According to different reliability require- ments, connection requests are divided into three classes, i.e., class high, class middle, and class low. Then two differentiated QoP provisioning schemes are proposed based on the class division, i.e., intraclass-shared re- source scheme (ICSR scheme) and cross-class-shared resource scheme (CCSR scheme). The former allows a connection to share backup resources only with those connections in the same class, whereas the latter enables the connections in different classes to share backup resources. Simulation results show that our proposed schemes could well provide differentiated reliability with PSRLG constraint and achieve a good balance between reliability and resource efficiency. Moreover, the CCSR scheme achieves lower blocking probability, lower re- source redundancy, and higher spectrum utilization without sacrificing reliability compared to the ICSR scheme. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in

Cites background from "Design and analysis of partial prot..."

  • ...× ðPSB;Ci PSB;s1 PSB;s2 · · · PSB;snÞ: (6)...

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  • ...1(d), when PSRLG r5 occurs, link (5, 6) on PW2 and link (6, 9) on PB2 may fail simultaneously; the second one is caused by the failure in competing for the backup resource....

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  • ...53(6) Optical Engineering 53(6), 066111 (June 2014)...

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References
More filters
01 Jan 2002
TL;DR: Various network and node architectures for different traffic -grooming scenarios are compared and discussed and it is expected that there will be much more interest on the mesh topology suitable for long-haul, widearea networks.
Abstract: The transmission capacity of a link in today’s optical networks has increased significantly due to wavelength-division multiplexing (WDM) technology. The network performance is now mainly limited by the processing capability of the network elements, which are mainly electronic. By efficiently grooming low-speed traffic streams onto high-capacity optical channels, it is possible to minimize this electronic processing and eventually increase the network performance. Traffic grooming is an emerging topic that has been gaining more research and commercial attention. Most previous research on traffic grooming is mainly based on the ring network topology. It is expected that there will be much more interest on the mesh topology suitable for long-haul, widearea networks. This paper reviews most of the recent research work on traffic grooming in WDM ring and mesh networks. Various network and node architectures for different traffic -grooming scenarios are compared and discussed. * This work has been supported by the National Science Foundation (NSF) under Grant Nos. NCR-9508239 andANI-9805286, and by Sprint Advanced Technology Laboratories (ATL).

273 citations

Journal ArticleDOI
TL;DR: This work investigates the survivable traffic-grooming problem for optical mesh networks employing wavelength-division multiplexing (WDM), and proposes effective heuristics for grooming a connection request with shared protection.
Abstract: We investigate the survivable traffic-grooming problem for optical mesh networks employing wavelength-division multiplexing (WDM). In the dynamic provisioning context, a typical connection request may require bandwidth less than that of a wavelength channel, and it may also require protection from network failures, typically fiber cuts. Based on a generic grooming-node architecture, we propose three approaches for grooming a connection request with shared protection: protection-at-lightpath level (PAL); mixed protection-at-connection level (MPAC); separate protection-at-connection level (SPAC). In shared-mesh protection, backup paths can share resources as long as their corresponding working paths are unlikely to fail simultaneously. These three schemes explore different ways of backup sharing, and they trade-off between wavelengths and grooming ports. Since the existing version of the problem for provisioning one connection request with shared protection is NP-complete, we propose effective heuristics. Under today's typical connection-bandwidth distribution where lower bandwidth connections outnumber higher bandwidth connections, we find the following: 1) it is beneficial to groom working paths and backup paths separately, as in PAL and SPAC; 2) separately protecting each individual connection, i.e., SPAC, yields the best performance when the number of grooming ports is sufficient; 3) protecting each specific lightpath, i.e., PAL, achieves the best performance when the number of grooming ports is moderate or small.

171 citations

Proceedings ArticleDOI
07 Nov 2002
TL;DR: The results show that the use of TDM provides substantial gains, especially for multi-fiber networks, and simulation based analyses are used to compare the proposed TDM architecture to traditional WR networks, both with and without wavelength conversion.
Abstract: We study routing and wavelength assignment for a circuit-switched time division multiplexed (TDM) wavelength-routed (WR) optical WDM network. In a conventional WR network, an entire wavelength is assigned to a given session (or circuit). This can lead to lower channel utilization when the individual sessions do not need the entire channel bandwidth. We consider a TDM-based approach to reduce this inefficiency. In this architecture, each wavelength is partitioned in the time-domain into fixed-length time-slots organized as a TDM frame. Multiple sessions are multiplexed on each wavelength by assigning a sub-set of the TDM slots to each session. Thus, given a session request with a specified bandwidth, the goal is to determine the route, wavelength and time-slot assignment (RWTA) that meets the request. This is similar to routing and wavelength assignment in WR networks. We present a family of RWTA algorithms and study the blocking performance. We use the existing shortest-path routing algorithm with a new link cost function, least resistance weight (LRW) function, that incorporates wavelength utilization information. We employ the known least loaded (LL) wavelength selection and present three variations of the least-loaded time-slot (LLT) algorithm. Simulation based analyses are used to compare the proposed TDM architecture to traditional WR networks, both with and without wavelength conversion. The goal is to compare the benefits of TDM and wavelength conversion towards improving performance in WR networks. The results show that the use of TDM provides substantial gains, especially for multi-fiber networks.

120 citations

Proceedings ArticleDOI
09 Aug 2001
TL;DR: A quantitative framework for best- effort protection of the optical layer is discussed, providing a way to bridge the gap between two known protection grades of fully protected connections vis-a-vis unprotected protection.
Abstract: In this paper we discuss a quantitative framework for best- effort protection of the optical layer. This framework provides a way to bridge the gap between two known protection grades of fully protected connections vis-a-vis unprotected protection. The framework allows to specify the probability with which the connection will be protected, providing the customer with a full range of protection guarantees at possibly different prices. Since connections may be partially protected, the required protection bandwidth can be reduced. The amount of protection bandwidth is shown to depend on an 'equivalent survivable bandwidth.' The framework also extends to preemptable (low priority) connections and to different ring architectures.

112 citations

Proceedings ArticleDOI
09 Aug 2001
TL;DR: A dynamic algorithm to obtain the optimal spare capacity on a wavelength on a link when a number of backup traffic streams are multiplexed onto it is presented.
Abstract: This paper addresses the problem of dynamically establishing dependable low-rate traffic stream connections in WDM mesh networks with traffic grooming capabilities. To establish a dependable connection, we set up link-disjoint primary and backup traffic stream paths between the source and destination and use backup multiplexing to reduce the overhead of backup traffic streams. We present a dynamic algorithm to obtain the optimal spare capacity on a wavelength on a link when a number of backup traffic streams are multiplexed onto it. We propose two schemes for grooming traffic streams onto wavelengths: Mixed Primary-Backup Grooming Policy (MGP) and Segregated Primary-Backup Grooming Policy (SGP). We illustrate how these schemes can be applied in a WDM mesh network scenario along with a routing and wavelength assignment algorithm. We conduct simulation experiments to evaluate the effectiveness of the proposed schemes on different network topologies, using different routing and wavelength assignment methods. The effect of change in granularity and change in the number of alternate paths on the grooming policies are also presented. From the simulation results, it is inferred that SGP is useful in network topologies, such as mesh-torus, characterized by good connectivity and a good amount of traffic switching and mixing at the nodes. On the other hand, MGP is useful in network topologies, such as a ring, characterized by low connectivity and high load correlation.

91 citations