Multi-path routing in optical WDM networks: Even versus uneven split bandwidth allocation
18 Jul 2010-pp 1-5
TL;DR: The performance analysis shows that the uneven splitting mechanism can substantially improve performance in terms of blocking probability (and other metrics) compared to the even splitting mechanism.
Abstract: In this paper, we investigate the design and performance of multi-path routing in optical wavelength division multiplexed (WDM) networks, that support traffic grooming. A circuit-switched network is considered, where connection requests arriving to the network have to be allotted an end-to-end path carrying the requested bandwidth. Traffic grooming implies that the capacity of a wavelength on a fiber link (e.g. OC-48) will be shared among several lower capacity connections (e.g. OC-3). In order to increase the network performance in terms of improved blocking probability and also to support survivable operation, a connection is split into multiple smaller sub-streams and carried on multiple sub-paths from source to destination. This is based on the Virtual Concatenation (VCAT) mechanisms used in SONET/SDH networks. One important constraint is that the differential delay among the sub-paths should be limited (e.g. 25 ms, 45 ms, etc.). In this paper, we consider mechanisms for splitting a connection request while maintaining the differential delay constraint. In particular, we study two schemes: even splitting of connection bandwidth among the constituent sub-paths; and uneven splitting of connection bandwidth. The work also considers sub-paths that are not necessarily link-disjoint. The performance analysis shows that the uneven splitting mechanism can substantially improve performance in terms of blocking probability (and other metrics) compared to the even splitting mechanism.
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TL;DR: Simulation results show that the multi-path VCAT scheme can efficiently utilize the overall spectrum resources with low blocking and confirm that migration from a pure fixed grid optical network to a pure flexible grid will be desirable for better network capacity utilization.
Abstract: A novel strategy is presented to operate a mixed fixed/flexible grid optical network which may be used to gradually migrate from a fixed to a flexible mode of operation. Routing and spectrum allocation (RSA) in an optical network where fixed and flexible grids co-exist using a multi-path sub-band virtual concatenation (VCAT) or split spectrum (SS) technique is considered. Mixed integer linear programming models and an efficient heuristic algorithm based on spectrum window planes are proposed for the RSA optimization. The results obtained for the static traffic demand indicate that it is operationally more convenient to use the multi-path VCAT only by itself in a mixed grid optical network to guarantee performance comparable to that of the joint multi-path and single-path VCAT case. Network performance is also evaluated in terms of bandwidth blocking probability (BBP) under a dynamic traffic demand. Simulation results show that the multi-path VCAT scheme can efficiently utilize the overall spectrum resources with low blocking. The results of studies with both static and dynamic traffic demands also confirm that migration from a pure fixed grid optical network to a pure flexible grid will be desirable for better network capacity utilization.
20 citations
Cites background from "Multi-path routing in optical WDM n..."
...[19] studied the performance of uneven and even traffic splitting mechanisms for multi-path routing in traffic groomed optical WDM mesh networks and showed that uneven splitting can help reduce blocking probability....
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TL;DR: This paper investigates approaches for the traffic grooming problem that consider connection holding-times and bandwidth availability and proposes algorithms that significantly reduce the blocking of connection requests yet promote a fair distribution of the network resources in relation to the state-of-the-art solutions.
12 citations
Cites background from "Multi-path routing in optical WDM n..."
...The work in [22] investigated the impact of uneven splitting of connections on the multipath traffic grooming problem....
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Proceedings Article•
20 Jul 2011TL;DR: Different approaches to achieve survivability in communication networks are surveyed, including link protection and path protection methodologies, and protection of mesh networks using p-cycles is covered.
Abstract: In this paper, we survey different approaches to achieve survivability in communication networks. Due to volume and throughput of data on optical networks, and catastrophic consequences of failures in those networks, we focus on survivability in optical Wavelength Division Multiplexing (WDM) networks. However, some of the techniques studied here are used in other types of networks as well. We will review the trade offs between protection switching versus dynamic restoration; and survivability in electronic layer versus optical layer. We go over link protection and path protection methodologies. We cover protection of mesh networks using p-cycles. Cross-layer design for survivability is considered; and problem of lightpath embedding is reviewed. Failure of a single link in the physical topology will not propagate to higher-level logical network, when we use such approaches. We tackle the problem of survivability in Shared Risk Link Groups (SRLGs) and Probabilistic SRLGs in face multiple network failures∗.
10 citations
01 Jan 2019
TL;DR: This paper summarizes the research status of SDON at home and abroad from the aspects ofSDON development overview, architecture and virtualization technology, and analyzes and forecast the challenges and development trends of the Software-Defined Optical Network.
Abstract: The development of optical networks has promoted the implementation of high-speed, broadband, long-distance and ultra-large-capacity transmission. However, with the avalanche growth of network scale and data traffic, traditional optical networks have been unable to carry various data center and cloud-based services. There is an urgent need for a more intelligent "brain" in the optical network. The Software-Defined Optical Network (SDON) proposes to solve the above problems effectively. This paper summarizes the research status of SDON at home and abroad from the aspects of SDON development overview, architecture and virtualization technology. And analyze and forecast the challenges and development trends of SDON.
2 citations
17 Apr 2012
TL;DR: The Passive Optical Network (PON) and Gigabit Passive optical Network (GPON) provide such a large bandwidth that it will never gives efficiency problem in a network.
Abstract: The dramatic increase of internet users and development of new high volume internet applications has a profound impact on design of next generation passive optical network (NG-PON). Today, most of the available networks are quite busy networks and as the number of nodes increases in the network, the communication over the network also increases. A reliable end packet delivery is always one of the basic requirements of a user as well as network. When the data is transferred over the network there are many major causes that can result packet loss, such as congestion over the network. Any kind of active or the passive attack over the network can make packet loss while transferring the data and also, heavy traffic over any network gives the problems like congestion, degradation in throughput. The Passive Optical Network (PON) and Gigabit Passive Optical Network (GPON) resolve most of the above defined problem. As it provide such a large bandwidth that it will never gives efficiency problem in a network. PON also resolve the bottleneck problem along with delay analysis over bottleneck congested network.
2 citations
References
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Book•
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13 Jan 2006
TL;DR: This paper presents a meta-modelling architecture for smart grids that automates the very labor-intensive and therefore time-heavy and expensive and expensive process of laying out and managing optical networks.
Abstract: Optical Networking: Principles and Challenges.- Enabling Technologies: Building Blocks.- Local, Access, and Metro Networks.- Single-Hop Networks.- Multihop Networks.- Optical Access Networks.- Optical Metro Networks.- Wavelength-Routed (Wide-Area) Optical Networks.- Routing and Wavelength Assignment.- Elements of Virtual-Topology Design.- Advanced Topics in Virtual-Topology Optimization.- Wavelength Conversion.- Survivable WDM Networks.- Light-Tree: Optical Multicasting.- Traffic Grooming.- Advanced Topics in Traffic Grooming.- All-Optical Impairment-Aware Routing.- Network Control and Management.- Optical Packet Switching (OPS).- Optical Burst Switching (OBS).
670 citations
"Multi-path routing in optical WDM n..." refers background or methods in this paper
...To provide these services efficiently, technologies such as Virtual Concatenation (VCAT) and Link Capacity Adaptive Scheme (LCAS) are currently employed in SONET/SDH networks [1], [5]....
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...Each wavelength is shared among multiple connections – this is referred to as “traffic grooming” [1]....
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TL;DR: This work surveys available bandwidth efficiency techniques for data transport, examines two relatively new mechanisms known as virtual concatenation and link capacity adjustment scheme (LCAS) that address inefficiencies and inflexibilities of SDH contiguous concatenations, and presents several potential applications for these technologies.
Abstract: Synchronous optical network (SONET) and synchronous digital hierarchy (SDH) contiguous concatenation have enabled high-speed networking in both metro and core networks for many narrow-band and broadband services including digital subscriber loop (DSL), cable, and Ethernet. Ironically, the tremendous success and rise of data traffic have, in part, put the focus on some of the inefficiencies and inflexibilities of SDH contiguous concatenation. Here I examine these shortcomings, survey available bandwidth efficiency techniques for data transport, examine two relatively new mechanisms known as virtual concatenation and link capacity adjustment scheme (LCAS) that address these issues, and finally present several potential applications for these technologies.
43 citations
"Multi-path routing in optical WDM n..." refers methods in this paper
...To provide these services efficiently, technologies such as Virtual Concatenation (VCAT) and Link Capacity Adaptive Scheme (LCAS) are currently employed in SONET/SDH networks [1], [5]....
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01 Dec 2004
TL;DR: This work considers the problem of minimizing the differential delay in a virtually concatenated Ethernet over SONET (EoS) system by suitable path selection by proposing two algorithms based on a modified link metric that linearly combines the original link weight and the inverse of that weight.
Abstract: We consider the problem of minimizing the differential delay in a virtually concatenated Ethernet over SONET (EoS) system by suitable path selection. The link capacity adjustment scheme (LCAS) enables network service providers to dynamically add STS-n channels to or drop them from a virtually concatenated group (VCG). A new STS-n channel can be added to the VCG provided that the differential delay between the new STS-n channel and the existing STS-n channels in the VCG is within a certain bound that reflects the available memory buffer supported by the EoS system. We model the problem of finding such a STS-n channel as a constrained path selection problem where the cost of the required (feasible) path is constrained not only by an upper bound but also by a lower bound. We propose two algorithms to find such a path. Algorithm I uses the well-known k-shortest-path algorithm. Algorithm II is based on a modified link metric that linearly combines the original link weight (the link delay) and the inverse of that weight. The theoretical properties of such a metric are studied and used to develop a highly efficient heuristic for path selection. Simulations are conducted to evaluate the performance of both algorithms in terms of the miss rate and the execution time (average computational complexity)
40 citations
"Multi-path routing in optical WDM n..." refers background or methods in this paper
...In [2], the authors present a K-shortest path algorithm and a minimum-cost flow based algorithm to select DD-constrained paths for routing....
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...In [4], the concept of Cumulative Differential Delay (CDDR) was introduced in order to better the exact memory requirements....
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...This gives rise to the problem of Differential Delay [2]....
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...6) Average Differential Delay: Table III presents the maximum number of sub-paths used and the average maximum differential delay of each connection....
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...Differential Delay (DD) is the difference between the propagation delays of the longest and shortest sub-paths....
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13 Mar 2005
TL;DR: This paper introduces the differential delay aware routing problem and shows that it is not only NP-complete but is also provably hard to approximate within a constant factor, but by transforming it into a flow routing formulation, it can derive effective, practical solutions.
Abstract: The virtual concatenation protocol in SONET/SDH has ushered in a novel routing paradigm that enables a circuit to be "split" and routed over multiple paths. However, this diverse routing causes differential delay among the paths which can impact service if not accounted for in the routing. In this paper, we introduce the differential delay aware routing problem and show that it is not only NP-complete but is also provably hard to approximate within a constant factor. However, by transforming it into a flow routing formulation, we can derive effective, practical solutions. We present various algorithms and use extensive simulations to show that they are a good match to an "ideal" integer linear programming formulation. We also highlight how the differential delay data allows individual link delays to be reverse-engineered. We propose three algorithms to derive link delays including one that leverages the flexibility in the virtual concatenation protocol bits. Given the rise of next-generation applications such as online games where latency information is key, this knowledge of link delays, heretofore only loosely approximated, enables the telecom infrastructure to be more effective in supporting these applications.
39 citations
11 Jun 2006
TL;DR: This paper extends the previous work on differential delay aware routing problem and shows that existing schemes do not accurately model the memory requirements of the network elements and develops a precomputation based algorithm that fares extremely well with the "ideal" integer linear programming formulation.
Abstract: The introduction of Virtual Concatenation protocol in SONET/SDH has enabled an efficient transport of various data rates by allowing the traffic to be split and routed over multiple paths. However, diverse routing of circuits introduces a differential delay among the member paths capable of impacting service if not compensated at the sink node or accounted during routing. In this paper, we extend the previous work on differential delay aware routing problem and show that existing schemes do not accurately model the memory requirements of the network elements. We introduce the concept of Cumulative differential delay to address the shortcomings of the previous approaches. We also incorporate the concept of flow awareness in differential delay routing and combine it with the cumulative differential delay concept to define Cumulative differential delay routing (CDDR) problem. We study the theoretical complexity of the CDDR problem and show that it is not only NP-complete but is also provably hard to approximate within a constant factor. However, we develop a precomputation based algorithm and show that it is extremely efficient and effective in practice. We use simulations to show that it fares extremely well with the "ideal" integer linear programming formulation.
35 citations
"Multi-path routing in optical WDM n..." refers methods in this paper
...In [4], the concept of Cumulative Differential Delay (CDDR) was introduced in order to better the exact memory requirements....
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