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32
Subpath Protection for Scalability and Fast Recovery in Optical . . .
, 2004
"... This paper investigates survivable lightpath provisioning and fast protection switching for generic meshbased optical networks employing wavelengthdivision multiplexing (WDM). We propose subpath protection, which is a generalization of sharedpath protection. The main ideas of subpath protection ..."
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Cited by 24 (5 self)
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This paper investigates survivable lightpath provisioning and fast protection switching for generic meshbased optical networks employing wavelengthdivision multiplexing (WDM). We propose subpath protection, which is a generalization of sharedpath protection. The main ideas of subpath protection are: 1) to partition a large optical network into smaller domains and 2) to apply sharedpath protection to the optical network such that an intradomain lightpath does not use resources of other domains and the primary/backup paths of an interdomain lightpath exit a domain (and enter another domain) through a common domainborder node. We mathematically formulate the routing and wavelengthassignment (RWA) problem under subpath protection for a given set of lightpath requests, prove that the problem is NPcomplete, and develop a heuristic to find efficient solutions. Comparisons between subpath protection and sharedpath protection on a nationwide network with dozens of wavelengths per fiber show that, for a modest sacrifice in resource utilization, subpath protection achieves improved survivability, much higher scalability, and significantly reduced faultrecovery time.
On Disjoint Path Pairs with Wavelength Continuity Constraint in WDM Networks
 in WDM networks; IEEE Infocom’2004
, 2004
"... In a WDM optical network, each fiber link can carry a certain set of wavelengths #= }. ..."
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Cited by 19 (6 self)
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In a WDM optical network, each fiber link can carry a certain set of wavelengths #= }.
Traffic Grooming for Survivable WDM Networks  Shared Protection
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
, 2003
"... This paper investigates the survivable trafficgrooming problem for optical mesh networks employing wavelengthdivision multiplexing (WDM). In the dynamicprovisioning context, a typical connection request may require bandwidth less than that of a wavelength channel, and it may also require protect ..."
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Cited by 17 (3 self)
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This paper investigates the survivable trafficgrooming problem for optical mesh networks employing wavelengthdivision multiplexing (WDM). In the dynamicprovisioning 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 groomingnode architecture, we propose three approaches—protectionatlightpath (PAL) level, mixed protectionatconnection (MPAC) level, and separate protectionatconnection (SPAC) level—for grooming a connection request with shared protection. In sharedmesh 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 existence version of the problem for provisioning one connection request with shared protection is N Pcomplete, we propose effective heuristics. Our findings are as follows. Under today’s typical connectionbandwidth distribution where lower bandwidth connections outnumber higher bandwidth connections, 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; and 3) protecting each specific lightpath—i.e., PAL—achieves the best performance when the number of grooming ports is moderate or small.
An InformationTheoretic View of Network Management
 IEEE TRANSACTIONS ON INFORMATION THEORY
, 2005
"... We present an informationtheoretic framework for network management for recovery from nonergodic link failures. Building on recent work in the field of network coding, we describe the input–output relations of network nodes in terms of network codes. This very general concept of network behavior as ..."
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Cited by 15 (2 self)
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We present an informationtheoretic framework for network management for recovery from nonergodic link failures. Building on recent work in the field of network coding, we describe the input–output relations of network nodes in terms of network codes. This very general concept of network behavior as a code provides a way to quantify essential management information as that needed to switch among different codes (behaviors) for different failure scenarios. We compare two types of recovery schemes, receiverbased and networkwide, and consider two formulations for quantifying network management. The first is a centralized formulation where network behavior is described by an overall code determining the behavior of every node, and the management requirement is taken as the logarithm of the number of such codes that the network may switch among. For this formulation, we give bounds, many of which are tight, on management requirements for various network connection problems in terms of basic parameters such as the number of source processes and the number of links in a minimum source–receiver cut. Our results include a lower bound for arbitrary connections and an upper bound for multitransmitter multicast connections, for linear receiverbased and networkwide recovery from all single link failures. The second is a nodebased formulation where the management requirement is taken as the sum over all nodes of the logarithm of the number of different behaviors for each node. We show that the minimum nodebased requirement for failures of links adjacent to a single receiver is achieved with receiverbased schemes.
Qualityofservice and qualityofprotection issues in preplanned recovery schemes using redundant trees
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATION
, 2003
"... In this paper, we study qualityofservice (QoS) and qualityofprotection (QoP) issues in redundant tree based preplanned recovery schemes for a singlelink failure in twoedge connected graphs and for a singlenode failure in twoconnected graphs. We present schemes (to be called GMFBG schemes) ..."
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Cited by 13 (0 self)
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In this paper, we study qualityofservice (QoS) and qualityofprotection (QoP) issues in redundant tree based preplanned recovery schemes for a singlelink failure in twoedge connected graphs and for a singlenode failure in twoconnected graphs. We present schemes (to be called GMFBG schemes) that generalize the schemes (to be called MFBG schemes) developed by Médard et al. to construct a pair of redundant trees, called red and blue trees, which guarantees fast recovery from any singlelink/node failure, as long as the failed node is not the root node. Using the GMFBG schemes, we study QoS issues relating to red/blue trees. We present effective heuristics for computing a pair of redundant trees with low average delay or small total cost. We develop an optimal algorithm for computing a pair of red/blue trees with maximum bandwidth. Furthermore, a pair of red/blue trees guarantees fast recovery from simultaneous multiple failures if it satisfies certain properties. This leads us to define the concept of QoP of a pair of red/blue trees. We present an effective heuristic to construct a pair of red/blue trees with high QoP. The paper concludes with a discussion of computational results that demonstrate the effectiveness of the different algorithms presented.
Fast Optical Layer Mesh Protection Using PreCrossConnected Trails
 IEEE/ACM Trans. Netw
, 2004
"... Abstract. Conventional optical networks are based on SONET rings, but since rings are known to use bandwidth inefficiently, there has been much research into shared mesh protection, which promises significant bandwidth savings. Unfortunately, most shared mesh protection schemes cannot guarantee that ..."
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Cited by 11 (0 self)
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Abstract. Conventional optical networks are based on SONET rings, but since rings are known to use bandwidth inefficiently, there has been much research into shared mesh protection, which promises significant bandwidth savings. Unfortunately, most shared mesh protection schemes cannot guarantee that failed traffic will be restored within the 50 ms timeframe that SONET standards specify. A notable exception is the pcycle scheme of Grover and Stamatelakis. We argue, however, that pcycles have certain limitations, e.g., there is no easy way to adapt pcycles to a pathbased protection scheme, and pcycles seem more suited to static traffic than to dynamic traffic. In this paper we show that the key to fast restoration times is not a ringlike topology per se, but rather the ability to precrossconnect protection paths. This leads to the concept of a precrossconnected trail or PXT, which is a structure that is more flexible than rings and that adapts readily to both pathbased and linkbased schemes and to both static and dynamic traffic. The PXT protection scheme achieves fast restoration speeds, and our simulations, which have been carefully chosen using ideas from experimental design theory, show that the bandwidth efficiency of the PXT protection scheme is comparable to that of conventional shared mesh protection schemes. 1.
Linear time construction of redundant trees for recovery schemes enhancing qop and qos
 IN PROCEEDINGS OF IEEE INFOCOM
, 2005
"... ... elegant recovery scheme (known as the MFBG scheme) using redundant trees. Xue, Chen and Thulasiraman extended the MFBG scheme and introduced the concept of quality of protection (QoP) as a metric of multifailure recovery capabilities for single failure recovery schemes. In this paper, we present ..."
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Cited by 10 (0 self)
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... elegant recovery scheme (known as the MFBG scheme) using redundant trees. Xue, Chen and Thulasiraman extended the MFBG scheme and introduced the concept of quality of protection (QoP) as a metric of multifailure recovery capabilities for single failure recovery schemes. In this paper, we present three linear time algorithms for constructing redundant trees for single link failure recovery in 2edge connected graphs and for single node failure recovery in 2connected graphs. Our first algorithm aims at high QoP for single link recovery schemes in 2edge connected graphs. The previous best algorithm has a running time of O(n 2 (m + n)), wherenand m are the number of nodes and links in the network. Our algorithm has a running time of O(m + n), with comparable performance. Our second algorithm aims at high QoS for single link recovery schemes in 2edge connected graphs. Our algorithm improves the previous best algorithm with O(n 2 (m + n)) time complexity to O(m + n) time complexity with comparable performance. Our third algorithm aims at high QoS for single node recovery schemes in 2connected graphs. Again, our algorithm improves the previous best algorithm with O(n 2 (m + n)) time complexity to O(m + n) time complexity with comparable performance. Simulation results show that our new algorithms outperform previously known linear time algorithms significantly in terms of QoP or QoS, and outperform other known algorithms in terms of running time, with comparable QoP of QoS performance.
Capacity design studies of spanrestorable mesh transport networks with sharedrisk link group (SRLG) effects
, 2002
"... We study the total capacity requirements of spanrestorable mesh network designs as the percentage of all possible dual failure combinations incident on a common node is increased. Our interest is in questions such as: Are there any guidelines or insights as to how many such SRLGs can be sustained b ..."
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Cited by 10 (0 self)
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We study the total capacity requirements of spanrestorable mesh network designs as the percentage of all possible dual failure combinations incident on a common node is increased. Our interest is in questions such as: Are there any guidelines or insights as to how many such SRLGs can be sustained before the capacity penalty becomes severe? Can we diagnose which SRLGs are the most limiting to overall network efficiency? When would it be worthwhile to take physical measures to eliminate a certain SRLG? In addressing these questions we provide a design formulation and procedure for planning any spanrestorable network for a known set of SRLGs. One finding of interest is that if all dual failure combinations incident to a common node are allowed for in the design, then nearly all other dual span failure combinations (any two spans in the network) will also be restorable. We also produce experimental results showing how total capacity depends on the relative number or frequency of coincident SRLGs and quantify how the type of SRLG will impact design costs.
An Information Theoretic View of Network Management
, 2003
"... We present an information theoretic framework for network management for nonergodic link failures. Building on recent work in the field of network coding, we describe the inputoutput relations of network nodes as codes and quantify network management by the logarithm of the number of different cod ..."
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Cited by 9 (2 self)
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We present an information theoretic framework for network management for nonergodic link failures. Building on recent work in the field of network coding, we describe the inputoutput relations of network nodes as codes and quantify network management by the logarithm of the number of different codes needed for different failure scenarios. We give bounds on network management requirements for various network connection problems in terms of basic parameters such as the number of source processes and the number of links in a minimum sourcereceiver cut. This is the first paper to our knowledge that looks at network management for general connections.
A directed cyclebased columnandcut generation method for capacitated survivable network design
 Networks
"... A network is said to be survivable if it has sufficient capacity for rerouting all of its flow under the failure of any one of its edges. Here, we present a polyhedral approach for designing survivable networks. We describe a mixedinteger programming model, in which sufficient slack is explicitly i ..."
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Cited by 8 (0 self)
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A network is said to be survivable if it has sufficient capacity for rerouting all of its flow under the failure of any one of its edges. Here, we present a polyhedral approach for designing survivable networks. We describe a mixedinteger programming model, in which sufficient slack is explicitly introduced on the directed cycles of the network while flow routing decisions are made. In case of a failure, flow is rerouted along the slacks reserved on directed cycles. We give strong valid inequalities that use the survivability requirements. We present a computational study with a columnandcut generation algorithm for designing capacitated survivable