We demonstrate, for the first time, 100Gb/s OTU4 over 400GE PLE (Private Line Emulation) across a packet network with OTN like service over a packet backbone. With the decrease of interest in OTN and emergence of IP over DWDM, PLE is an attractive proposal in the IETF for provisioning leased-lines (which continue to be high-margin services for providers). PLE involves the mapping of high-speed OTN services (OTU4 typically, but also OTU2) on to packets and use a smart signaling infrastructure of the packet switched network to provision pseudo-wires. We developed PLE hardware and interfaces it with IP routers to create 100Gb/s OTU4 over 400Gb/s Ethernet. We showed deterministic latency and low jitter in addition to significant network-wide power saving (up to 50%). Results also conform to the requirements of traditional circuit (OTN) communication.

Network Function Virtualization (NFV) is a promising technology that can transform how internet service providers deliver their services. However, recent studies have identified several challenges in adopting NFV. Two key challenges are central to the operation and capacity planning of NFV Data Centers (DCs): (i) Service Function Chain (SFC) realization —determining if a new request with a known profile can be accommodated—and (ii) Network Function Virtualization (NFV) traffic bounds estimation —estimating the total traffic that a data center can handle considering all service requests and their performance constraints. To address these challenges, we propose a model that leverages stochastic network calculus to effectively dimension an NFV DC while ensuring delay and availability bounds for all service requests. Our theoretical model provides a mathematical framework to assess the realization of a single SFC request without delving into the specifics of the realization process. We utilize established availability-aware Virtual Network Function (VNF) placement patterns to obtain traffic bounds essential to planning data center capacity. We analyze NFV data center traffic under various scenarios over a Fat-tree DC topology. The results demonstrate that data center capacity is significantly influenced by the VNF placement strategy. Additionally, for data centers hosting latency-sensitive services, Service Level Objective (SLO) constraints on availability and delay are crucial in determining the number of such requests that can be accommodated.

We present Vercel, a network verification and automatic fault rectification tool that is based on a computationally tractable, algorithmically expressive, and mathematically aesthetic domain of linear algebra. Vercel works on abstracting out packet headers into standard basis vectors that are used to create a port-specific forwarding matrix$\mathcal {A}$, representing a set of packet headers/prefixes that a router forwards along a port. By equating this matrix$\mathcal {A}$and a vector b (that represents the set of all headers under consideration), we are able to apply least squares (which produces a column rank agnostic solution) to compute which headers are reachable at the destination. Reachability now simply means evaluating if vector b is in the column space of$\mathcal {A}$, which can efficiently be computed using least squares. Further, the use of vector representation and least squares opens new possibilities for understanding network behavior. For example, we are able to map rules, routing policies, what-if scenarios to the fundamental linear algebraic form,$\mathcal {A}x=b$, as well as determine how to configure forwarding tables appropriately. We show Vercel is faster than the state-of-art such as NetPlumber, Veriflow, APKeep, AP Verifier, when measured over diverse datasets. Vercel is almost as fast as Deltanet, when rules are verified in batches and provides better scalability, expressiveness and memory efficiency. A key highlight of Vercel is that while evaluating for reachability, the tool can incorporate intents, and transform these into auto-configurable table entries, implying a recommendation/correction system.

We examine how to provide applications with dedicated bandwidth and guaranteed latency in a programmable mission-critical network. Unlike other SDN approaches such as B4 or SWAN, our system Tuneman optimizes both routes and packet schedules at each node to provide flows with sub-second bandwidth changes. Tuneman uses node-level optimization to compute node schedules in a slotted switch and does dynamic routing using a search procedure with Quality of Service– (QoS) based weights. This allows Tuneman to provide an efficient solution for mission-critical networks that have stringent QoS requirements. We evaluate Tuneman on a telesurgery network using a switch prototype built using FPGAs and also via simulations on India’s Tata Network. For mission-critical networks with multiple QoS levels, Tuneman has comparable or better utilization than SWAN while providing delay bounds guarantees.

This paper proposes Trailnet, a deep reinforcement learning approach to predict the output port (of a router) for an IP packet based on its destination IP address. Trailnet attempts to replace the forwarding table at an IP router with a computational model. To optimally learn each router’s forwarding decisions, we propose to train the Artificial Neural Network (ANN) of Trailnet with value iteration and stochastic gradient descent. Through the value iteration algorithm, Trailnet estimates the cost of IP packet forwarding along different ports of a router and eventually selects a port that optimizes a cost function. We evaluate the generalization capability of the ANN on two sufficiently large service provider’s network topologies containing millions of IP addresses. Our evaluations show that Trailnet achieves high accuracy and fast inference time for predicting the correct output ports for incoming IP packets. Our results support the claim of replacing forwarding tables and distributed protocols (for computing shortest paths) with a computation model while operating at a high line rate in IP routers.

Network slicing is a key enabler for next-generation 5G services. Slices are designed to offer different services by conjoining virtual network functions (VNFs) through a logical network. We propose a dynamic slicing algorithm, which is based on utility theory and facilitates the growth, provisioning, dimensioning and deletion of network slices. The proposed algorithm is based on a utility model that regulates the virtual topology of VNFs in data-centers. The algorithm optimizes the number of slices as well as instantiated VNFs, thereby creating/modifying and destroying network slices of appropriate granularity. In addition, we also propose a stochastic optimization formulation, which handles uncertainty in service requests. We simulate the algorithm for a multi-data-center model with a large set of slices. Our results indicate dynamism, robustness and scalability of the proposed algorithm.

We consider the availability of applications in a large provider network environment. Our primary goal is to design a service provider network for high-availability using multiple components that have different availability. Initially, we model a modern provider architecture that is spread across the access, metro and core regions. We want to answer the specific question as to what amount of over-the-top (OTT) services can be provisioned over a given network while achieving a predesired availability value. To this end, we formulate a constrained optimization model whose objective is revenue maximization subject to availability measures. Two heuristics are also proposed that fathom the breadth of the virtual network function (VNF) deployment parameters: VNF licensing cost and server utilization. A simulation model presents comparative data for efficiency and server utilization as well as validates our optimization model. The results stress the importance of our optimization model in planning the network, as well as planning VNF placement ahead in time.

SDNs could be a game changer for next generation provider networks. OpenFlow (OF) - the dominant SDN protocol, is rigid in its South Bound Interface (SBI) - any new protocol field that the hardware must support, must await complete OF standardization. In contrast, OF alternatives such as protocol oblivious forwarding (POF) and ForCES have simpler schemes for insertion of new protocol identifiers. Even with these there is an inherent limitation on network hardware - the tables must support specific table format and configuration at each node as per protocol semantics. We ask the question - can we design an open system - one that is carrier-class, yet able to meet the requirements of any protocol forwarding/action with a minimal set of dataplane function. We propose bitstream, a low-latency, source-routing based scheme that can support new protocols, be compatible with existing protocols and facilitate a minimum semantic set for acting on a packet. A prototype is built to show bitstream working.

Network Function Virtualization (NFV) has the potential to transform the way providers do business. In particular, NFV can be an ideal solution for the current provider situation - whereby revenue is decreasing (due to competition), bandwidth requirements are increasing and the cost of provisioning increases with the bandwidth requirements. In such a situation, NFV can be a real game-changer, in terms of providing alternate avenues towards saving CapEx and OpEx, while also facilitating a new set of portfolio services to the end user. We model a realistic service provider and measure the impact of NFV on current network deployment. We then compute price-points at which it would start to make sense for a provider to indulge in NFV. Our simulations and optimizations study has built-in robustness that facilitate stability of the results across traffic variations as well as provider types.

We propose a scalable data-center architecture and associated protocol using the double use of optics in both the backplane as well as the frontplane, segregated by an electrical SDN switch. The advantage of our architecture is seemingly infinite scalability in conjunction with the ability to transport large chunks of data (with full bisection bandwidth) between servers across the data center. We present the architecture, system design, scalability issues as well as power profiles. Further, we present a protocol that facilitates software defined networking and communication within the data center. A simulation model is shown that validates the architecture for different manifestations of the data-center using various services and variations of the architecture. The proposed architecture results in low latency and excellent throughput, while reducing total cost of wiring within the data-center.

As a major driving force for adopting cloud computing, continuous cost reduction has been constantly pursued by cloud users. For a group of users with heterogeneous cloud resource demands, it may be possible for them to buy resources in a collaborative way in order to save the purchase cost, which is known as group-buying in business. While group-buying can benefit cloud users in principle, the question is how to design an implementation scheme to support group-buying on the cloud market. In this paper, we address the question by studying a coalition formation game, aiming to design a way under which the users can form stable coalitions for group-buying. It turns out that group-buying on the cloud market is challenging in that most popular solution concepts may fail to constitute stable coalitions. In order to sustain group-buying for cloud services, we propose a new solution concept, contractually group stable, which is an extension of an existing concept in the literature. We show that this new solution concept can guarantee the existence of stable coalitions, making group-buying always possible on the cloud market. We also develop computing algorithms for solving the coalition formation game under our concept. Computational experiments show that our concept can bring in substantial cost reduction for cloud users.

Software Defined Networking (SDN) has brought a paradigmatic shift in the networking industry and has led to significant benefits in the data-center and enterprise network domains. The service provider networks that form the largest segment of networking industry, are now evaluating SDN technologies for adoption. In this paper, we present a SDN framework for service provider networks and report the first field trial of SDN in a tier-1 service provider domain. The proposed SDN framework is built using Carrier Ethernet and augmented with recently proposed Segment Routing paradigm manifested through Software Defined-Carrier Ethernet Switch Routers (SD-CESRs). Carrier Ethernet on account of its distinct, programmable control plane and Segment Routing through its source routing capabilities facilitates SDN implementation. The SD-CESRs are deployed in a tier-1 service provider network in the metropolis of Mumbai. The SDN framework is extended through specific APIs to enhance revenue bearing services portfolio of the service provider and performance results from the field are shown to validate the benefits of SDN adoption.

Segment routing has recently been proposed in the IETF towards making IP/MPLS networks service-oriented and efficient. Segment routing involves identifying paths at the source node using adjacency identifiers conjoined together to create a source-routed path. To this end, we propose a transport paradigm that will act as an enabler towards implementing segment routing in service provider networks. Specifically, we use Carrier Ethernet that is gaining acceptance as an IP/MPLS carrier technology. We propose the use of our modification of Carrier Ethernet called Omnipresent Ethernet (based on source routed binary labels embedded in an Ethernet frame) towards implementing segment routing. We evaluate segment routing for large service provider networks and understand scalability limitations of source routing. To absolve the scalability issues, a hierarchical segment routing (H-SR) scheme that uses special nodes called Swap-Nodes is proposed. Three techniques for swap-node selection based on centrality paradigms that facilitate and enhance scalability of segment routing are put forth. A test-bed is built to validate segment routing along with a simulation model to evaluate the proposed hierarchical segment routing scheme.

Carrier Ethernet is rapidly being deployed in the metropolitan and core segments of the transport network. One of the emerging flavors of Carrier Ethernet is the IEEE 802.1Qay PBB-TE or Provider Backbone Bridging-Traffic Engineering standard. PBB-TE relies on the assignment of a network-specific Virtual Local Area Network (VLAN) tag, called the Backbone VLAN ID or BVID that is used in conjunction with a backbone Media Access Control (MAC) address for forwarding. The 12-bit BVID along with 48-bit Backbone MAC address are used to forward an Ethernet frame. The assignment of BVIDs in a network is critical, given that there are only 4094 possible assignments, especially for those paths that are overlapping in the network graph and incident at the same destination. While the only way to scale is to reuse BVIDs, this method can lead to a complication if the same BVID is allocated to an overlapping path. To the best of our knowledge, this is the first instance of isolating this problem of limited BVID availability which rises only due to graphical overlap between services. We formulate and solve this as a constrained optimization problem. We present optimal and heuristic algorithms to solve the BVID problem. The optimal approach solves the `static' case, while the heuristic can solve both the `static' and the `dynamic' cases of the BVID allocation problem. Results show that the developed heuristics perform close to the optimal and can be used in commercial settings for both the static and dynamic cases.

We propose a framework called Fission that facilitates good scalability in terms of supporting large number of servers as well as a protocol that allows efficient, low-latency communication within the data-center. The Fission concept combines an optical backplane (using UDWDM - ultra dense wavelength division multiplexing based speedup in conjunction with a series of optical buses) to physically scale the data-center. The Fission framework uses an efficient protocol that is a modification of Carrier Ethernet. The working of the Fission architecture from a systems and a protocol perspective are described. Issues such as scalability, protocol working and support for services within the data-center are discussed. A simulation study validates our design for latency and scalability - two critical aspects of data-center design.

In elastic optical networks, the spectrum consecutive and continuous constraints may cause the so-called spectrum fragmentation issue, degrading spectrum utilization, which is especially critical under dynamic traffic scenarios. In this paper, we propose a novel multipath de-fragmentation method which aggregates spectrum fragments instead of reconfiguring existing spectrum paths. We propose an optimization model based on Integer Linear Programming (ILP) and heuristic algorithms and discuss the practical feasibility of the proposed method. We show that multipath routing is an effective de-fragmentation method, as it improves spectral efficiency and reduces blocking under dynamic traffic conditions. We also show that the differential delay issue does not present an obstacle to the application of multipath de-fragmentation in elastic optical networks.

Service provider networks are becoming increasingly complex with multi-domain and multi-layer capabilities. Multi-layer optimization has been proposed as a mechanism for planning provider-networks focused on optimizing revenue and reducing capital expenditure. In this paper, we study multi-layer optimization from the perspective of deploying services so as to reduce the capital expenditure in provider-networks. To this end we propose a 3-layer network hierarchical model based on IP, OTN and DWDM technologies. In this paper, we propose an optimization model, a heuristic algorithm and their solution methods. While the optimization model deals with the network planning cases involving static traffic demands, the heuristic algorithm solves the dynamic case. We also develop a simulation model to validate our optimization and heuristic approaches.

Carrier Ethernet is emerging as a new transport paradigm across metropolitan and core networks. Provider Backbone Bridging-Traffic Engineering or PBB-TE was standardized in the IEEE as 802.1Qay as a mechanism to provide a dedicated transport service at the Ethernet layer. This paper discusses implementation of the PBB-TE standard using shared memory switch architecture, though the same architecture argument can be extended to implement MPLS-TP (the other manifestation of Carrier Ethernet). While shared memory switch architectures have been well investigated, we provide to the best of our knowledge the first carrier-class aggregation switch implemented in a single Field Programmable Gate Array (FPGA). This low-cost implementation paves the way for advances in Carrier Ethernet technologies to be made available to the access part of the network using rapid prototyping and commercial off the shelf components. The switch architecture supports multiple QoS levels and implements circuit emulation to transport traditional circuit services over a packet backbone. A rigorous simulation study validates our effort.

Carrier Ethernet has rapidly advanced itself to become an important technology for metro transport. PBB-TE or Provider Backbone Bridging-Traffic Engineering is one of the mechanisms being considered for the deployment of Carrier Ethernet. PBB-TE relies on the assignment of a network-specific VLAN tag called the BVID that is further dependent on customer and service provider VLAN tags, service provider MAC address and an intermediate instantiation service tag. Given the limited availability of BVIDs in a network on account of the basic tag format, it is desired to reuse tags to facilitate larger service instance provisioning. To the best of our knowledge, this is the first instance of isolating this problem of limited BVID availability, which is further reduced to a constrained optimization problem. We present optimal (static) and heuristic (dynamic) algorithms to the solution of the BVID problem. Results show significant betterment as compared to commercial practices for both the static and dynamic case.

The Reach Optimized Architecture for Multi-rate Transport System or ROAMTS is presented, analyzed, and evaluated, leading to the case for non-ITU.T grid optics. The ROAMTS architecture promises better fiber utilization as well as the capability to adhere to the requirements of higher-line-rates especially, at 40 Gbps and 100 Gbps, in metropolitan and regional networks. The paper showcases the promise of ROAMTS whose inherent philosophy is that of treating each channel/signal in a unique way unlike conventional WDM systems. This philosophy of no-one-size-fits-all is explained from an architectural perspective. Treating each demand uniquely to maximize the total fiber utilization as well as to extend the signal-reach leads to a combinatorial-optimization problem - of finding which is the best way of allocating traffic within the ROAMTS framework. A second objective is to measure the reduction of muxponders - subsystems that multiplex lower line-rate signals into a higher granular signal using an electronic multiplexer. Performance results show significant improvement over traditional ITU.T-WDM grid systems.

Cloud computing and IT-service provisioning is critical for the growth of enterprises in being able to provision computationally intensive applications. A high-speed networks infrastructure is necessary for the proliferation of cloud computing to meet disparate IT application demands. Light-trails - a generalization of lightpath with ability to provision sub-wavelength demands, meet dynamic bandwidth needs and cater to optical multicasting in a low-cost platform are investigated as a candidate technology for cloud computing. A time-slotted light-trail system is assumed and an algorithm is proposed based on utility concepts. Scheduling connections over light-trails in a timely manner to meet the tasks of an IT-service are considered. Memory resource management as a constraint is further incorporated in the algorithm thereby making the IT application pragmatically reside over the light-trails infrastructure. An exhaustive simulations study showcases the benefits of light- trails for cloud computing - the results obtained are over a wide range of services with serial, parallel and mixed set of constituent tasks.

The merging, management and utilization of pervasive, idle computing devices using a dynamic communication infrastructure leads to the concept of computational grids. A computational grid enables enterprises to efficiently use distributed computing entities in a cost-effective setup for emerging com

LiTPiCs were proposed as a marriage of two innovative technologies - light-trails and photonic integrated circuits - as a solution to extend metro networks in regional domains and provide dynamism in bandwidth allocation for emerging services. Light-trails which are a generalized lightpath, essentially formed by an optical bus provide sub-wavelength optical grooming and facilitate dynamic bandwidth allocation amongst constituent nodes. Communication within a light-trail is all-optical thereby limiting their reach to a few node-spans. In parallel, photonic integrated circuits were developed that proposed the system on a chip concept enabling 3R regeneration of optical signal using embedded lasers and receivers on a single Indium Phosphide substrate. PIC technology has given rise to the concept of digital optical networks which have the capability to increase reach and commoditize metro networks. By conjoining the light-trail and PIC technologies we proposed LiTPiC which is essentially preserves light-trail properties while enhancing their reach. In this paper we study algorithms for scheduling traffic in a LiTPiC. We consider both the static case and the dynamic case - when traffic is known and not known apriori. Further we will establish a lower and upper bound that would facilitate an evaluation procedure of our algorithms.

This paper studies distributed multi-domain, multi-layer provisioning (grooming) in IP/MPLS-DWDM networks. Although many multi-domain studies have emerged over the years, these have primarily considered "homogeneous" network layers. Meanwhile, most grooming studies have assumed idealized settings with "global" link state across all layers. Hence there is a critical need to develop practical distributed grooming schemes for real-world networks consisting of multiple domains and technology layers. Along these lines, a detailed hierarchical framework is proposed to implement inter-layer routing, distributed grooming, and setup signaling. The performance of this solution is analyzed using simulation studies and future directions high-lighted.

While the introduction of new Ethernet-based wide-area solutions, such as provider-backbone bridging traffic engineering- PBB-TE, paves a way for Ethernet to become a carrier class service, it is restricted to the metro area and hence unable to provision global end-to-end communication. In this paper, we propose a new scheme for all-Ethernet wide area networking that involves a unique addressing and routing mechanism, and leads to a scalable, hierarchical and service-oriented transport network architecture. The scalability is achieved by means of abstraction of any irregular physical topology into a regular logical topology, based on the concept of binary trees. The regular logical topology is represented with logical 1 x 2 Ethernet switches as the fundamental building blocks which allow switching using a unique binary addresses in a simple and automated fashion. We propose an evolutionary architecture to provide end-to-end Ethernet routes using binary addresses embedded in stacked VLAN tags on native Ethernet frames, in line with the emerging standards. The results show that a significant simplification of wide-area internetworking can be achieved, while supporting carrier-grade network performance with all-Ethernet features.

A light-trail is a generalization of a lightpath such that multiple nodes can take part in communication along the path. A light-trail exhibits properties of dynamic provisioning, optical multicasting and sub-wavelength grooming and architecturally is analogous to a shared wavelength optical bus with an Out-Of-Band (OOB) control channel. The bus feature results in a node that has a large pass-through loss, and hence restricts the size of a light-trail to metro environments. Within a bus the OOB control channel allows for dynamic real-time arbitration. Due to this limitation, it is difficult to extend the light-trail concept to regional and core networks. In this paper we propose a method to provide multihop communication in light-trails thereby relaxing the limitation in hop count, as well as enhancing reach of communications. We propose node architecture and protocol requirements for creating Multi-hop Light-trails (MLTs). We then discuss design issues for MLTs in regional area networks through problem formulation. A simulations study validates MLTs.

Advances in SONET/SDH technologies have introduced novel features for improved services mapping and provisioning, enabling many new avenues for new Carrier Ethernet support. However Ethernet-over-SONET studies have mostly focused on provisioning point-to-point Ethernet private line offerings. This paper considers the more challenging case of provisioning multi-point-to-multi-point Ethernet LAN services over advanced SONET/SDH networks and presents novel strategies based upon connection group overlays. Detailed simulation results are also presented along with directions for future work.

Light-trail is proposed as a candidate to carry IP traffic over wavelength division multiplexing (WDM) optical networks given its capability of accommodating multi-granularity traffic by time-division multiplexing (TDM). Light-trail's unidirectional shared-media multicast nature makes it hard to implement distributed access control and restricts that at most one packet transmission can take place at any time. Recently, opportunistic optical hyperchannel was proposed to improve light-trail by permitting easy distributed access control. In this paper, we propose a set of distributed access control protocols, namely, 1-persistent protocols, for opportunistic optical hyperchannels to maximize the throughput and provide fair service among contending nodes by taking their inherent advantage of adaptive space-division multiplexing (SDM). We also point out a possible generalization of opportunistic optical hyperchannels by removing the restriction of linear structure, and demonstrate possible applications of such a generalization.

Enterprise networks form the backbone of corporate communication. Ethernet is the default layer-2 transport protocol and has undergone decades of constant innovation and improvisation. We propose a solution called CAMPUS for enterprise networks primarily based on end-to-end Ethernet. This all-Ethernet campus networking paradigm is designed for large enterprises or even metro networks relegating IP functions to only large core routers, while making good use of carrier-class Ethernet switches in the access and the metro area. Implementation of the CAMPUS solution is discussed from a theoretical as well as hardware perspective. Service provisioning, scalability and performance features are evaluated through extensive simulations model.

Data center networking (DCNs) is a fast emerging enterprise application that is driving metropolitan bandwidth needs. This paper evaluates the needs of this emerging IT-centric, bandwidth voluminous and service rendering application from a metro optical networking perspective. We identify a set of needs called CAVALIER (consolidation, automation, virtualization, adaptability, latency, integration, economy and reliability) that are underlying requirements for a network to support DCN services. The CAVALIER requirements are met by proposing a metro optical solution which is based on light-trail ROADM technology. Light-trails exhibit properties such as dynamic bandwidth provisioning, optical multicasting, sub-wavelength granular support and low-cost for deployment. Adapting light-trails to DCN needs is discussed in this paper through engineering requirements and network-wide design. Each aspect of the CAVALIER requirement is then mapped on to light-trail technology. Simulation results are shown to lead to performance betterments.

Recently, light-trail is becoming an appealing architecture for WDM networks which have been considered as promising backbone of the next generation network. Light-trail can inherently support multicast given its bus nature. In this paper, we study how to use the minimum number of light- trails to form a multicast tree for supporting the given multicast session. The problem for general light-trail WDM networks is proved to be NP-hard. Two auxiliary graphs will be proposed to transform the problem into minimum steiner tree problem that many effective algorithms can be applied. We then show that the same problem in light-trail WDM ring networks can be solved in polynomial time. The simulations show the effectiveness of our work.

Recent studies on inter-domain DWDM networks have focused on topology abstraction for state summarization, i.e. transforming a physical topology to a virtual mesh, tree, or star network. Although these schemes give very good inter- domain blocking reduction, associated inter-domain routing overheads are significant, particularly as the number of domains and border OXC nodes increase. To address these scalability limitations, novel routing update triggering policies for multi-domain DWDM networks are developed. The performance of inter-domain lightpath RWA and signaling schemes in conjunction with these strategies is then studied in order to gauge the overall effectiveness of these approaches.

A light-trail is a generalized lightpath that enables multiple nodes to statistically share an optical communication path (wavelength bus). A light-trail is different from a lightpath on account of its unique node architecture - that enables formation of unidirectional wavelength buses. A node in a light-trail supports signal flow characteristics of drop-and-continue as well as passive addition leading to formation of the bus. Apart from the node architecture, another differentiation between light-trails and lightpaths is in the use of out-of-band control channel (optical supervisory channel - OSC) for dynamic communication. The combined effect of a unique node architecture and out-of-band control channel enables light-trails to provide capability of sub-wavelength grooming, dynamic provisioning and optical multicasting. These features offered by light-trails are critical for next generation emerging applications such as VoIP, video-on-demand (VoD), triple-play and pseudo-wire edge-to-edge emulation (PWE3). Current OSC based control channel requires engineering enhancement to provision dynamic and bandwidth efficient services over light-trails. We investigate into the control channel hierarchies in light-trail networks to provision these emerging services. Centralized, distributed, static and dynamic control mechanisms are proposed. Light-trail control for provisioning next generation services is considered through theory and simulation.

A recent advance in high-speed networks is the concept of Photonic Integrated Circuits (PICs) on an Indium Phosphide substrate, allowing miniaturization and integration of multiple OE and EO modules in a chip. PICs have the potential to do away with the opto-electronic bandwidth mismatch as well as result in severe cost reduction, hence questioning the need for all-optical networking. In this paper we analyze the impact of this digital optical networking concept by combining PIC technology with an all-optical solution - light-trails, resulting in a new solution called LiTPiC (Light-Trail Photonic Integrated Circuit). LiTPiCs offer the best of both digital and all-optical worlds. By enabling selective (and on-demand) regeneration of the signal, we are able to enhance the reach of all-optical light-trails. In addition, we are able to partition light-trail buses into multiple geographically disjoint sub-buses called PIC-Trails, thus for the first time introducing wavelength reuse within a light-trail. The LiTPiC concept gives PICs a new direction - that of being a technology enabler for next generation services using ROADM (Reconfigurable Optical Add-Drop Multiplexer) architecture and a complementary solution to the light-trail technology.

The theoretical error performance of double space time transmit diversity (DSTTD) system with optimum combining receiver is analyzed in this paper. By employing both spatial multiplexing and transmit diversity in one system, DSTTD provides practical tradeoff between system spectral efficiency and diversity gain. We derive exact analytical expressions to describe the symbol error rate for DSTTD systems. The effects of both diversity gain and antenna interference introduced by spatial multiplexing are quantified in the results. In addition, the performance of DSTTD system with successive interference cancellation is also investigated. Simulation results are in excellent agreement with the theoretical results obtained in this paper.

Abstract — Clos networks are an important class of switching networks due to their modular structure and much lower cost compared with crossbars. For routing I/O permutations of Clos networks, sequential routing algorithms are too slow, and all known parallel algorithms are not practical. We present the algorithm-hardware codesign of a unified fast parallel routing architecture called distributed pipelining routing (DPR) architecture for rearrangeable nonblocking and strictly nonblocking Clos networks. The DPR architecture uses a linear interconnection structure and processing elements that performs only shift and logic AND operations. We show that a DPR architecture can route any permutation in rearrangeable nonblocking and strictly nonblocking Clos networks in ¦¨§� © �� � steps. The same architecture can be used to carry out control of any group of connection/disconnection requests for strictly nonblocking Clos networks in ¦¨ § © ��� steps. Several speeding-up techniques are also presented. This architecture is applicable to packet and circuit switches of practical sizes. Index Terms: Clos network, permutation routing, circuit switching, packet switching, rearrangeable nonblocking,

A new scalable optical network infrastructure SMART is proposed based on light-trails and hypernetwork architecture. The underlying physical network of SMART is a reconfigurable WDM network with reconfigurability distributed over network nodes. The reconfigurable node architecture is capable of dynamically setting up, modifying, and tearing down connections that consist of multi-access hyperchannels, which are an extension of light-trails. Like light-trails, hyperchannels are used to efficiently utilize bandwidth in subwavelength granularity. Hyperchannels and hyperpaths (hybrid connection paths) make SMART scalable. Equipped with a menu of switching techniques and connection types, SMART is able to manage optimized connections, and enforce individual service qualities and overall network performance. SMART network combines the best features of optics and electronics, making the network highly intelligent. Various virtual networks can be easily constructed over SMART. SMART encompasses the best features of existing mature electrical and optical network technologies, making these technologies as special cases. SMART is evolvable with backward compatibility. SMART is customizable for constructing LANs, MANs and WANs, and for access and transport. SMART provides an excellent alternative for the next generation Internet.

Dynamic bandwidth allocation for upstream transmission in EPONs has gathered significant attention. Maximizing utilization is inversely related to dynamic bandwidth allocation. We propose an auctioning mechanism for bandwidth allocation with a view to dissolution of the paradox between efficiency (utilization) and dynamism. While conventional bandwidth auctioning schemes pose efficiency as well as fairness issues, our extensions overcome these. We propose three extensions: to increase efficiency we propose a K- out-of-N auctioning mechanism; to promote dynamism and reduce bandwidth starvation, we enhance the auctioning mechanism by introducing strategic scaling; and to cater to services we propose a bid computation mechanism that is uniquely tailored to reflect different service requirements. Through a simulation model we evaluate the performance of our scheme for latency, dynamism, efficiency and blocking probability.

A new rearrangeable nonblocking photonic multi- log2N network DM(N) is introduced. It is shown that DM(N) network simultaneously possesses many good properties, including those of existing rearrangeable nonblocking multi-log2N networks and new ones such as O (log N) -time fast parallel self-routing and nonblocking multiple-multicast.

Trains as a mass transport system are a strong application case for coarsely granular bandwidth-on-demand networking. Multiple trains time-sharing the same track, traveling at a significant speed and containing a large number of bandwidth savvy users represents a premier motivation for the merger of optical and wireless communications. Wireless delivery methods alone cannot suffice the need for such a large moving mass of bandwidth intensive users. We propose a method to efficiently integrate a wireless network over a flexible optical backbone. The proposed method is built upon the light-trails optical platform and involves a unique control layer that adapts to an overlaid wireless network. Here, we propose a cross-layer protocol that enables seamless communication for these "light-trains". We also show benefits in terms of throughput, end-to-end delay, bandwidth efficiency and scalability of such a scheme through a simulation study.

A light-trail is a generalization of a lightpath such that multiple nodes can take part in communication along the path. A light-trail is a good candidate for optical layer traffic grooming. In this paper we investigate the grooming aspect of light-trails from a sub-system perspective. We introduce a new sub-system called burstponder card that enables efficient grooming of traffic in a light-trail. We describe the implementation of the burstponder card using FPGA and burst-mode optics. We show experiment results on efficiency and latency for a 4-node light-trail network demonstrating it as an effective solution for optical grooming.

We propose an architecture and an algorithm for the realization of a pragmatic framework for optical packet transport. The architecture enables the transport of IP packets over optical frames in a network. While doing so, it relaxes the need for address recognition as well as for high speed switching, the two key hindering factors that have prevented contemporary optical packet transport solutions from being deployed. We propose the light-frames architecture for sub-lambda level provisioning of optical paths. The idea is to create a logical topology that allows N/sup 2/ connectivity using optical paths that are by themselves sublambda provisionable yielding in packet transport. We show that by using substantially fewer resources, we can provide N/sup 2/ connectivity in arbitrary graphs to support optical packet transport.

The rapid growth of IP centric communication in worldwide networks and the parallel mass deployment of fiber based WDM networks have propelled IP over WDM being considered as an eventual solution for bandwidth on demand to customers. Contemporary optical networks are, however, based on lightpath communication and a lightpath represents end-to-end optical circuits from source to destination. Light-trails are a generalization of lightpaths, such that multiple nodes along a trail can participate in time differentiated communication over the same established trail. Managing and setting up of light-trails in order to cater to IP centric traffic is a key to the success of IP centric communication at the optical layer. A light-trail represents an open optical path that allows multiple users to communicate without the need for switch reconfiguration at any user node, the light-trail itself being static. IP communication on the other hand represents a bursty traffic flow often characterized by spurts or bursts of data. The goal of this paper is to show how to create efficient light-trails based virtual topology for a given network traffic flow. We first describe a tree-shaped variant of light-trail, called the clustered light-trail (CLT) and then present optimization techniques for satisfying the given IP centric communication requirements, using the light-trails framework that is very flexible, despite being basically a static mechanism.

In this paper we propose a solution to implement Ethernet over PON using two unidirectional channels for access networks. The protocol called TUR is efficient and scalable and easy to implement using conventional mature technologies. We discuss strategies to deploy both upstream as well as downstream communication. Possible end-user designs are also discussed in connection to the protocol. A simulation study verifies the protocol and compares to contemporary solutions.

Light-trails communication (Chlamtac and Gumaste, 2003) proposes a solution for implementing a conceptual framework for IP centric communication in the optical domain which is a combination of node architecture and protocol for realizing efficient optical communications from IP bursts to dynamic lightpaths. In this paper we introduce a Light-trails solution that is applicable to mesh networks. Contrary to existing proposals for IP type communication in the optical domain light-trail node architecture also presents the first practically implementable solution to enable optical transport with mature technology, nonstringent optical switching requirements, and potentially presents a cost effective alternative to electronics in supporting IP networks.

We propose a new type of wireless system, which is to provide for multimedia, bandwidth upon demand and quality of service (QoS) to the user. The system proposes to disable the problem caused by the unavailability of wired access by providing large bandwidths upon demand to individual users. The scheme proposes the use of optical beams in interconnecting mobile-telephone-switching-offices (MTSO) with each other using distinct WDM measures in a multihop scenario. Small microcells capable of growing themselves and reducing back to their macro size are employed. Traffic is dealt with by the anomalous expansion and contraction of these cells. A high data rate to individual users is provided by a FH-CDMA based system whereby the chip rate becomes proportional to the channel quality. This ad-hoc method of adaptive coding helps the user maintain a uniform data rate throughout time. The benefits of this approach are dealt with in great detail and issues of reliability and hand-off as well as system diversity are dealt with. As a further approach the authors suggest the interaction of this system with an ail-optical underlaying network.