Optical Wdm Networks and Multicasting (original) (raw)
Related papers
WDM multicasting in IP over WDM networks
Proceedings. Seventh International Conference on Network Protocols
Supporting WDM multicasting in an IP over WDM network poses interesting problems because some WDM switches may be incapable of switching an incoming signal to more than one output interface. An approach to WDM multicasting based on wavelength-routing, which constructs a multicast forest for each multicast session so that multicast-incapable WDM switches do not need to multicast, was proposed and evaluated in [5]. Such an approach requires global knowledge of the WDM layer. In this paper, we study WDM multicasting in an IP over WDM network under the framework of Multiprotocol Label Switching (MPLS) [10, 11] using optical burst/label switching (OBS/OLS) [6]. We propose a protocol which modifies a multicast tree constructed by distance vector multicast routing protocol (DVMRP) into a multicast forest based on the local information only.
Design Considerations For Efficient multicast WDM Network Scalable Architecture
Transaction on Network …, 2011
In this paper, we present a method for designing a passive optical based single-hop wavelength division multiplexing multicast network architecture that can achieve a scalable structure and form the basis of a wavelength efficient single-hop WDM network. The proposed architecture minimizes the number of wavelengths required for efficient multicast service and also minimizes tunability requirement of the transceivers. The network size scalability is achieved by adding transmitters and receivers to the designated groups. We show that the proposed system can accommodate large tuning delays and keeps with suitable throughput when the number of wavelength is equal to the number of nodes. We also show that the design can lead to a scalable structure while minimizing the number of wavelengths and tunability of the transceivers required for an efficient multicast service resulting in an improved system throughput and delay performance.
Performance Analysis of a Multicast System in WDM Single-hop Broadcast-and-Select Optical Network
2006
In this paper we use an approximate analytical solution to show the influence of tuning delay on the system performance under different network conditions and characteristics such as number of wavelength channels and offered load. We also examine the effect of average packet delay and tuning time on receiver throughput. Finally, we demonstrate the channel blocking probability versus network offered load characteristics.
An efficient mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks
Optical Fiber Technology, 2014
This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated. grooming 1. Introduction 1 As wavelength division multiplexing (WDM) networks are taking over the 2 dominant role in the Internet backbone [1], it is widely believed that IP over 3 WDM networks will be a key component of the next-generation Internet [2, 3]. 4 The emerging networking technologies, such as Multi-Protocol Label Switching 5 (MPLS) [4], Generalized MPLS (GMPLS) [5], User Network Interface (UNI) 6 [6], path computation element (PCE) [7], etc., are also paving the way for such 7 network revolution. 8 An IP/MPLS over WDM network has two different layers. The IP/MPLS 9 layer consisting of label switching routers (LSRs) and label switched paths (L-10 SPs) is the carrier network, and it delivers requests between its end users; the 11 WDM layer consisting of optical-cross-connects (OXCs) and fiber links is the 12 transport network, and it provides dynamic connectivity services to the upper-13 layer client(s) in the form of lightpaths [8]. A lightpath may span several optical 14 links, and it has to be assigned the same wavelength along its route if all OXCs 15 do not have wavelength conversion capability. 16 For the interconnection between the IP/MPLS layer and the WDM layer 17 networks, three architectural alternatives, namely, overlay, peer and augmented 18 models, have been proposed [9]. In the overlay model, the two network layer-19 s are independent of each other, and the only information exchange between 20 them is for service requests and responses. While in the peer model, a unified 21 control plane is maintained, in charge of all network control and management. 22 The augmented model tries to make a compromise between the two by allow-23 ing certain information to be shared between the two layers; however, there 24 is still no consensus on what kind of information should be shared. Adapting 25 a peer-model approach allows the network transmission provisioning problem 26 to be conveniently mapped into a network flow problem with complete topol-27 ogy and capacity information on both layers. In practice, however, since the 28 2 IP-layer and the WDM layer networks are usually owned by different network 29 operators, overlay model is widely accepted as the most practical one for near-30 term deployment [9]. The emergence of service oriented optical networks further 31 demonstrates the feasibility of such model [10]. While extensive work has been 32 done on transmission provisioning in peer model networks [11-16], studies on 33 overlay network model are still relatively limited, and mostly only for handling 34 unicast traffic [17-20]. 35 Multicast is an efficient way of disseminating information from one source to 36 multiple destinations simultaneously [21]. In recent years, as Internet applica-37 tions, such as multi-player gaming, video conferencing and interactive distance 38 learning, etc., are becoming increasingly popular, multicasting becomes one of 39 the essential capabilities in modern networks. In the traditional IP network-40 s, multicast is realized relying on the IP router's copying capability; while in 41 WDM networks, it relies on the OXCs' light-splitting capability. To support 42 physical-layer multicasting in WDM networks, a generalized lightpath concept, 43 named light-tree, was proposed [22]. 44 The bandwidth required for a typical multicast session is on the order of 45 megabits per second (Mbps), which is much smaller compared to the 2.5 − 40 46 gigabits per second (Gbps) capacity that can be steadily provided by a sin-47 gle wavelength channel in today's WDM networks. To efficiently utilize the 48 wavelength capacity, several multicast sessions are usually packed together on-49 to wavelength channels for transmission. Such a process is known as multicast 50 traffic grooming [23]. 51 The early-stage work on multicast traffic grooming mainly focused on the 52 static scenario where traffic is known a prior [24-26]. As more agile networking 53 technologies are being adopted in optical networks, however, multicast traffic 54 tends to show its dynamic nature. Hence dynamic multicast traffic grooming 55 problem becomes an important research issue. Different algorithms utilizing 56 either lightpath, or light-tree, or both for dynamic multicast traffic grooming 57 have been proposed [27-37]. 58 Compared to the extensive interests received in peer model networks, dy-59 3 namic multicast traffic grooming in overlay IP over WDM networks, however, 60 has not received much attention in the past years. Since the two layers of the 61 network are managed by independent owners with very limited information ex-62 changes in between, routing decisions made on one layer may lead to inefficient 63 resource utilizations on the other layer. To the best of our knowledge, up till now 64 only two methods have been proposed for tackling this problem. Both methods, 65 which will be reviewed in Section 2, are easy to be implemented, yet not free 66 from the inherent limits caused by limited information exchanges between the 67 two layers. 68 Our previous study [20] on unicast traffic grooming in overlay networks shows 69 that, by letting the two layers agree on a definition of the cost for setting up 70 a new lightpah and allowing the IP/MPLS-layer operator to keep record of the 71 recent service requests that have been supported by the WDM layer network, 72 the IP/MPLS-layer owner can make better routing decisions and improve net-73 work performance significantly [20]. To extend such results to multicast traffic 74 grooming, however, requires nontrivial work. The issues to be studied include 75 the definition of the cost for setting up new connections (not necessarily new 76 lightpaths), the routing method, and more. Further, how to improve the effi-77 ciency of WDM-layer network resource sharing is also an important issue. 78 This paper addresses the dynamic multicast traffic grooming problem in 79 overlay IP/MPLS over WDM networks. To help relax the constraint imposed 80 by limited information exchanges in overlay networks while improving resource 81 sharing in traffic grooming process, an efficient overlay multicast provisioning 82 (OMP) mechanism is proposed. By jointly utilizing a historical data learning 83 (DL) scheme on the IP/MPLS layer for link cost estimation, and a lightpath 84 fragmentation (LPF) based method on the WDM layer for improving resource 85 sharing, OMP aims to minimize the bandwidth blocking ratio (BBR), which is 86 defined as 87 BBR = ∑ Blocked request bandwidth ∑ Bandwidth of all requests 4 Extensive simulation results show that OMP significantly outperforms the exist-88 ing methods under different traffic loads, in networks with limited or unlimited 89 optical port resources. It is also found that the IP-layer DL contributes more 90 to improve network performance than the WDM-layer LPF method. Effects 91 of other factors, including definition of new connection cost and WDM-layer 92 routing method, on OMP performance are also evaluated. 93 The remainder of the paper is organized as follows. Section 2 presents the 94 network model, the definition of the problem, and some most closely related ex-95 isting results. Section 3 describes the proposed OMP mechanism. Performance 96 evaluations are carried out in Section 4. Section 5 concludes the paper. 97 2. Network Models, Previous Work and Problem Statement 98 2.1. Overlay IP/MPLS over WDM Network Model 99 A typical overlay IP/MPLS over WDM network as shown in Fig. 1 is con-100 sidered in the paper. With the overlay architecture, the operations and manage-101 ment of the two layers' networks are independent of each other; the IP/MPLS 102 layer is an integrated service provider (ISP) delivering the service requests be-103 tween its end users, while the WDM layer is the bandwidth provider providing 104 the required connectivity services to its upper layer client(s).
IEICE Transactions on Communications, 2010
We propose a scheme of MultiCast Routing and Wavelength Assignment (MC-RWA) to establish light-tree for dynamic multicast session for the Wavelength Division Multiplex (WDM) network by choosing the wavelength that leads to a reduction in blocking probabilities by using a parameter Δ. Δ is defined as the overall reduction of connectivity of the nodes in the network caused by a wavelength assignment process when using a particular wavelength, and we assign wavelength resources to the multicast session by choosing the Δ which leads to smallest reduction in connectivity. Through computer simulation, we show that the proposed scheme has lower blocking probabilities when compared with minimum cost scheme under the condition that wavelength conversion is not allowed.
Multicast traffic grooming in WDM networks
OptiComm 2003: Optical Networking and Communications, 2003
This paper considers the problem of grooming multicast traffic in WDM networks, with arbitrary mesh topologies. The problem is different from grooming of unicast traffic, since traffic can be delivered to destinations through other destinations in the same set, or through branching points. The paper presents an optimal Integer Linear Programming (ILP) formulation in order to minimize the cost of the network in terms of the number of SONET Add/Drop Multiplexers (ADM). The formulation also minimizes the number of wavelength channels used in the network, and does not allow bifurcation of traffic. Since the ILP formulation is able to solve limited size problems, the paper also introduces a heuristic approach to solve the problem. Telephone: 1 515 294 2295 * Without loss of generality, in this paper we will assume that the Synchronous Optical Networks (SONET) is being used as a higher layer in WDM networks. † This can be shown by considering a counter example of a two node, one fiber network, where the fiber has two wavelengths. If the wavelength capacity is three units, and there are three demands between the two nodes, each of two units, all demands will be accommodated, hence allowing bifurcation.
A Survey on Wavelength Division Multiplexing (WDM) Networks
ICTACT Journal on Communication Technology
Communication networks have emerged as a source of empowerment in today's society. At the global level, the Internet is becoming the backbone of the modern economy. The new generations in developed countries cannot even conceive of a world without broadband access to the Internet. The inability of the current Internet infrastructure to cope with the wide variety and ever growing number of users, emerging networked applications, usage patterns and business models is increasingly being recognized worldwide. The dynamic growth of Internet traffic and its bursty nature requires high transmission rate. With the advances and the progress in Wavelength Division Multiplexing (WDM) technology, the amount of raw bandwidth available in fiber links has increased to high magnitude. This paper presents a survey on WDM networks from its development to the current status. Also an analysis on buffer size in optical networks for real time traffic was performed.
Multicast Capacity of Packet-Switched Ring WDM Networks
IEEE Transactions on Information Theory, 2000
Packet-switched unidirectional and bidirectional ring wavelength division multiplexing (WDM) networks with destination stripping provide an increased capacity due to spatial wavelength reuse. Besides unicast traffic, future destination stripping ring WDM networks also need to support multicast traffic efficiently. This article examines the largest achievable transmitter throughput, receiver throughput, and multicast throughput of both unidirectional and bidirectional ring WDM networks with destination stripping. A probabilistic analysis evaluates both the nominal capacity, which is based on the mean hop distances travelled by the multicast packet copies, and the effective capacity, which is based on the ring segment with the highest utilization probability, for each of the three throughput metrics. The developed analytical methodology accommodates not only multicast traffic with arbitrary multicast fanout but also unicast and broadcast traffic. Numerical investigations compare the nominal transmission, receiver, and multicast capacities with the effective transmission, receiver, and multicast capacities and examine the impact of number of ring nodes and multicast fanout on the effective transmission, reception, and multicast capacity of both types of ring networks for different unicast, multicast, and broadcast traffic scenarios and different mixes of unicast and multicast traffic. The presented analytical methodology enables the evaluation and comparison of future multicast-capable medium access control (MAC) protocols for unidirectional and bidirectional ring WDM networks in terms of transmitter, receiver, and multicast throughput efficiency.
Multicasts on WDM all-optical multistage interconnection networks
Proceedings. Eighth International Conference on Parallel and Distributed Systems. ICPADS 2001, 2001
Wavelength-division multiplexing (W D M) optical networks provide huge bandwidth by allowing multiple data streams transmitted simultaneously along the same optical fiber, with each stream assigned a distinct wavelength. A key issue o n W D M optical networks is to minimize the number of wavelengths f o r realizing a routing request. Let W be the number of wavelengths supported by a W D M optical network. For a routing request R which needs 1 wavelengths, i f I 5 W then R can be realized in one round of routing. However, when 1 > W , multiple rounds of routing f o r R are required. I n this case, it is important t o minimize the number of routing rounds. Multicast is to transmit a data stream f r o m one input t o multiple outputs (one-to-many), a fundamental communication pattern in many applications. I n this paper, we study the problem of minimizing the number of wavelengths and the number of routing rounds f o r realizing a set R = { (u , v) } of multicasts, where each output v receives a data stream f r o m exactly one input U , o n the n-dimensional W D M all-optical multistage interconnection networks (MINs). For the network with wavelength converters, we show that any set of multicasts can be realized by 2 r (n-1) f (k + ') 1 wavelengths in k rounds of routing. For one round of routing, the upper bound 2r(n-1)f21 is tight to the lower bound. W e also give algorithms f o r multicasts o n the network without wavelength converters. Computer simulation results show that any set of multicasts can be realized in at most two rounds of routing o n the network with practical size.
Multisource multicasting in IP/MPLS over WDM networks
Photonic Network Communications, 2010
Multicasting applications such as multimedia conferencing, online multiplayer interactive games, and distance learning are becoming increasingly popular. With multiprotocol label switching, Internet protocol networks can offer quality of service and traffic engineering capabilities. This article introduces several approaches for multisource multicast sessions in the context of IP over WDM networks and evaluates their performance in terms of blocking probability, time complexity, and memory consumption. Our simulation study shows that among all the approaches, the newly proposed approach, known as one Bidirectional Tree with Just enough bandwidth reserved on each link of the tree, achieves the best overall performance.