G.N. Rouskas

G.N. Rouskas
North Carolina State University | NCSU · Department of Computer Science

PhD

About

309
Publications
32,606
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7,201
Citations
Citations since 2017
31 Research Items
929 Citations
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2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150

Publications

Publications (309)
Article
We revisit the classical spectrum allocation (SA) problem, a fundamental subproblem in optical network design, and make three contributions. First, we show how some SA problem instances may be decomposed into smaller instances that may be solved independently without loss of optimality. Second, we prove an optimality property of the well-known firs...
Article
Presents information and current topics of interest to the global communications industry.
Article
Full-text available
Elastic optical networks employing multi-core fibers (MCF-EON) have the potential to expand significantly the transmission capacity of optical transport. However, wide deployment of such networks depends on addressing effectively two critical challenges: inter-core crosstalk, which may cause serious signal performance degradation in an MCF link, an...
Article
Network function virtualization (NFV), with its perceived potential to accelerate service deployment and to introduce flexibility in service provisioning, has drawn a growing interest from industry and academia alike over the past few years. One of the key challenges in realizing NFV is the service chain routing problem, whereby traffic must be rou...
Article
Elastic optical networks (EON) technology in combination with space division multiplexing (SDM) is considered as having the potential to expand the transmission capacity of optical transport networks. However, inter-core crosstalk may cause serious signal impairment in a multi-core fiber (MCF) links. At the same time, scheduled lightpath demands, f...
Article
Full-text available
The Routing and Spectrum Assignment (RSA) problem is NP-Hard so searching the entire problem space is not applicable. Many decomposition algorithms rely on reducing the search space in the routing space and applying heuristics algorithm in the spectrum assignment sub-problem. This is not necessarily a right solution as the ignored routing tables ma...
Article
The optical network on chip (ONoC) paradigm has emerged as a promising solution to multi-core/many-core processor systems for offering enormous bandwidth and low power consumption. As chip multiprocessors (CMPs) scale to unprecedented numbers of cores, the performance of next-generation CMPs will be bounded by the process yield and power density of...
Article
Full-text available
Elastic optical networks (EONs) are increasingly used to interconnect data centers. As inter-datacenter traffic is expected to continue to grow at high rates for the foreseeable future, it becomes imperative to address the respective growth in power consumption within EONs. In this paper, we take the first steps towards enhancing the energy efficie...
Article
Virtual request partitioning is an essential subproblem of two common problems in virtual networks, namely, virtual network embedding (VNE) and virtual machine placement (VMP). In this study, we consider a network-aware variant of the problem where the objective is to partition a virtual request so as to minimize the total amount of inter-cluster t...
Article
Full-text available
Flexi-grid elastic optical networks (EONs) provide a promising infrastructure for meeting the high-bandwidth and low-latency requirements of interconnecting datacenters. Since failures of high-capacity fiber links prevent users from accessing cloud services and lead to large amounts of data loss, much recent research has focused on inter-datacenter...
Article
Network service orchestration across heterogeneous networks needs an open marketplace where the services advertised by the providers in different domains can be purchased for short-term or long-term time scales. The authors present two design paradigms and evaluate two corresponding prototypes which provide a framework for network services to be pu...
Article
The routing and spectrum assignment (RSA) problem has emerged as the key design and control problem in elastic optical networks. Distance-adaptive spectrum allocation exploits the tradeoff between spectrum width and reach to improve resource utilization by tailoring the modulation format to the level of impairments along the path. In this paper, we...
Article
Full-text available
Distance adaptive spectrum allocation exploits the tradeoff between spectrum width and reach to improve resource utilisation by tailoring the modulation format to the level of impairments along the path. The authors first show that the distance-adaptive routing and spectrum assignment (DA-RSA) problem is a special case of a multiprocessor schedulin...
Article
All-optical networks are the aspiration of bandwidth-greedy applications providers and users such as telecom operators and scientific research centres. Because of the limitations of current network infrastructures, some optical switching paradigms have been proposed. Among these paradigms, optical burst switching (OBS) is seen as the most appropria...
Article
Full-text available
We study the spectrum assignment (SA) problem in ring networks with shortest path (or, more generally, fixed) routing. With fixed routing, each traffic demand follows a predetermined path to its destination. In earlier work, we have shown that the SA problem can be viewed as a multiprocessor problem. Based on this insight, we prove that, under the...
Article
Full-text available
The routing and spectrum assignment problem has emerged as the key design and control problem in elastic optical networks. In this work, we show that the spectrum assignment (SA) problem in mesh networks transforms to the problem of scheduling multiprocessor tasks on dedicated processors. Based on this new perspective, we show that the SA problem i...
Article
The Internet has been a key enabling technology for many new distributed applications and services. However, the deployment of new protocols and services in the Internet infrastructure itself has been sluggish, especially where economic incentives for network providers are unclear. In our work, we seek to develop an "economy plane" for the Internet...
Article
In recent years, OFDM has been the focus of extensive research efforts in optical transmission and networking, initially as a means to overcome physical impairments in optical communications. However, unlike, say, in wireless LANs or xDSL systems where OFDM is deployed as a transmission technology in a single link, in optical networks it is being c...
Article
Optical burst switching (OBS) is the most favourable switching paradigm for future all-optical networks. Burst assembly is the first process in OBS and it consists of aggregating clients packets into bursts. Assembled bursts wait for an offset time before being transmitted to their intended destinations. Offset time is used to allow burst control p...
Article
The routing and spectrum assignment (RSA) problem has emerged as the key design and control problem in elastic optical networks. In this work, we provide new insight into the spectrum assignment (SA) problem in mesh networks by showing that it transforms to the problem of scheduling multiprocessor tasks on dedicated processors. Based on this new pe...
Article
Full-text available
We presenta simple yet effective enhancement to the operation of the Ethernet passive optical network (EPON) multipoint control protocol (MPCP) for wavelength division multiplexing (WDM) EPON. The enhancement, inspired by our earlier work in a related but different context, allows the optical line terminal (OLT) to perform look-ahead scheduling on...
Conference Paper
We articulate how the area of traffic grooming may be combined with the ChoiceNet Future Internet architecture, to create an agile system capable of reflecting both provider and customer interests on an ongoing basis as network conditions change.
Conference Paper
Full-text available
Hierarchical traffic grooming facilitates the control and management of multigranular WDM networks. We define the hierarchical virtual topology and traffic routing (H-VTTR) problem, the grooming-specific subproblem of traffic grooming, and we present a suite of ILP formulations to solve it. The formulations represent various tradeoffs between solut...
Article
Full-text available
We consider the traffic grooming problem, a fundamental network design problem in optical networks. We review a typical integer linear program formulation considered in the literature, and we identify two challenges related to this formulation in terms of scalability and wavelength fragmentation. We then propose a new (to our knowledge) solution ap...
Article
Survivable MPLS technologies are crucial in ensuring reliable communication services. The fast reroute (FRR) mechanism has been standardized to achieve fast local repair of label switched paths (LSPs) in the event of link or node failures. We present a suite of hybrid protection schemes for MPLS networks that combine the well-known p-cycle method w...
Conference Paper
We present a scalable formulation for the traffic grooming problem in WDM ring networks. Specifically, we modify the ILP formulation to replace the constraints related to routing and wavelength assignment (RWA), typically based on a link approach, with a new set of constraints based on the maximal independent set decomposition (MISD) that we recent...
Conference Paper
The problem of providing an agile, energy-aware, flexible optical network architecture is one of the challenges in optical networking in the coming decade. A key element in this challenge is the balancing of the benefits to customer and provider, and creating an agile system capable of reflecting both provider and customer interests on an ongoing b...
Conference Paper
Full-text available
We consider the virtual topology and traffic routing (VTTR) problem, a subproblem of traffic grooming that arises as a fundamental network design problem in optical networks. The objective of VTTR is to determine the minimum number of light-paths so as to satisfy a set of traffic demands, and does not take into account physical layer constraints; a...
Conference Paper
We present a simple yet effective enhancement to the operation of the EPON multipoint control protocol (MPCP) that results in significant performance gains across the whole range of traffic loads. The enhancement, inspired by our earlier work in a related but different context, allows the OLT to perform look-ahead scheduling on the upstream channel...
Conference Paper
The growing number of applications that use the Session Initiation Protocol (SIP) to manage media sessions over IP is placing increasing demands on the SIP proxy servers (SPS) that make up the core of the SIP network. In this work we investigate the performance of OpenSIPS, an open source SPS. We have collected a large set of experimental data to c...
Article
Full-text available
Network virtualization refers to a broad set of technologies. Commercial solutions have been offered by the industry for years, while more recently the academic community has emphasized virtualization as an enabler for network architecture research, deployment, and experimentation. We review the entire spectrum of relevant approaches with the goal...
Conference Paper
RWA is a fundamental problem in the design and control of optical networks. We propose link selection algorithms that reduce the size of the link-based ILP formulation for RWA by pruning redundant link decision variables. The resulting formulation scales well to mesh topologies representative of backbone and regional networks. In our experiments, t...
Conference Paper
Computer networks, in particular the Internet, represent essential infrastructure for business, government, military, and personal communication. Several recent trends in technology and network use have pushed the capabilities required of the Internet beyond what can be provided by the currently deployed infrastructure. To address these limitations...
Conference Paper
RWA is a fundamental problem in the design and control of optical networks. We introduce the concept of symmetric RWA solutions and present a new ILP formulation to construct optimally such solutions. The formulation scales to mesh topologies representative of backbone and regional networks. Numerical results demonstrate that the new formulation ac...
Article
Full-text available
There has been a great interest in defining a new network architecture that can meet the needs of a future Internet. One of the main challenges in this context is how to realize the many different technical solutions that have developed in recent years in a single coherent architecture. In addition, it is necessary to consider how to ensure economi...
Article
Full-text available
In ancient times, unless somebody was prepared to travel, man could only communicate as far as he could shout. Methods were then developed to enable communications to extend over longer distances, using trumpets, beacon fire, flags, etc. It was not until the inauguration of telegraphy (by W. Cooke and C. Wheatstone in England in 1839, and by S. Mor...
Conference Paper
We present a link pair design scheme for MPLS-TP node protection, which combines p-cycle method with fast reroute (FRR) technology. Numerical results indicate that this approach is successful in combining advantages of p-cycle and FRR.
Conference Paper
Full-text available
We develop a new solution approach for the traffic grooming problem by decomposing it into a virtual topology and traffic routing (VTTR) subproblem, and the RWA subproblem.We solve the VTTR subproblem with a new partial LP relaxation technique.
Conference Paper
Full-text available
This paper is a tutorial, which discusses reference model; architectural principles and objectives of network virtualization. Network virtualization projects, challenges and future directions are also discussed.
Conference Paper
We develop a new solution approach for the traffic grooming problem by decomposing it into a virtual topology and traffic routing (VTTR) subproblem, and the RWA subproblem. We solve the VTTR subproblem with a new partial LP relaxation technique.
Conference Paper
Survivable MPLS technologies are crucial in ensuring reliable communication services. The fast reroute (FRR) mechanism has been standardized to achieve fast local repair of label switched paths (LSPs). We present a hybrid survivability scheme for MPLS networks that combines the well-known p-cycle method with FRR technology. While with pure FRR back...
Conference Paper
Network operators offer a variety of tiered services in which users may select only from a small set of tiers which offer progressively higher levels of service. Service bundling, whereby several services are combined together and sold as a single package, is also common in the telecommunications market. We consider the problem of determining optim...
Conference Paper
Full-text available
We address the issue of ensuring the integrity and privacy of communications in optical networks. To this end, we extend the traffic grooming concept to encompass flow isolation considerations through a multi-class traffic model. We develop, solve, and compare ILP formulations that ensure that only traffic components within the same class are groom...
Article
In the past few years there has been vigorous debate regarding the size of buffers required at core Internet routers. Recent arguments supported by theory and experimentation show that under certain conditions, core router buffer sizes of a few tens of packets suffice for realizing acceptable end-to-end TCP throughputs. This is a significant step t...
Article
The design of fair packet schedulers involves a tradeoff between implementation complexity, on one hand, and delay and fairness guarantees, on the other. In this paper, we present tiered-service fair queuing (TSFQ), a new scheduler that exploits certain properties of Internet traffic to speed up the bottleneck operations related to virtual time com...
Conference Paper
The design of packet schedulers involves a tradeoff between implementation complexity, on one hand, and delay and fairness guarantees, on the other. In this paper, we present worst-case fair bin sort queuing (WBSQ), a new scheduler that has good worst-case fairness and delay properties, yet has low complexity and is amenable to simple hardware impl...
Article
We consider the problem of providing QoS guarantees to Grid users through advance reservation of resources. Advance reservation mechanisms provide the ability to allocate resources to users based on agreed-upon QoS require-ments and increase the predictability of a Grid system, yet incorporating such mechanisms into current Grid environments has pr...
Article
WDM rings are now capable of supporting more than 100 wavelengths over a single fiber. Conventional link and path formulations for the RWA problem are inefficient due to the inherent symmetry in wavelength assignment and the fact that the problem size increases fast with the number of wavelengths. Although a formulation based on maximal independent...
Article
QoS-aware video streaming is demonstrated on an optical network using a service-oriented architecture and a NetFPGA-based optical control plane. Dynamic optical power fluctuations are either compensated or the lightpath is rerouted to ensure the QoS.
Article
The Dynamic Recursive Unified Internet Design (DRUID) is a future Internet design that unifies overlay networks with conventional layered network architectures. DRUID is based on the fundamental concept of recursion, enabling a simple and direct network architecture that unifies the data, control, management, and security aspects of the current Int...
Article
Many existing and emerging Scientific high-end applications (E-science) require end-to-end circuits interconnecting Grid resources for large data transfers. A few advanced networks, mainly National Research and Education Networks (NRENs), such as Surfnet, National Lambda Rail and Internet 2, now provide mechanisms for end-users to reserve and provi...
Article
The architecture of the modern Internet encom- passes a large number of principles, concepts and assumptions, that have evolved over several decades. In this paper, we argue that while the current architecture houses an effective design, it is not itself effective in enabling evolution. To achieve the l atter goal, we introduce the SILO architectur...
Article
We consider a hierarchical approach for traffic grooming in large multiwavelength networks of a general topology. Inspired by similar concepts in the airline industry, we decompose the network into clusters, and select a hub node in each cluster to groom traffic originating and terminating locally. At the second level of the hierarchy, the hub node...
Conference Paper
WDM rings are now capable of supporting more than 100 wavelengths over a single fiber. Conventional link and path formulations for the RWA problem are inefficient due to the inherent symmetry in wavelength assignment and the fact that the problem size increases fast with the number of wavelengths. Although a formulation based on maximal independent...
Conference Paper
Power-awareness in networking attracts more attention as the trends in the energy consumption of the Internet raise growing concerns about the environmental impacts and sustainability of the network expansion. Building energy efficient equipment is definitely an integral part of the solution. However, such a strategy should be complemented with app...
Conference Paper
In the previous chapter we considered a market scenario in which all users receive the same value from the service offered by the network operator, or equivalently, all users are characterized by the same utility function U(x). A market in which all users value a service (or product) similarly is said to be inelastic [20]. Certain essential goods (...
Article
Many network operators offer some type of tiered service, in which users may select only from a small set of service levels (tiers). Such a service has the potential to simplify a wide range of core network functions, allowing the providers to scale their operations efficiently. In this work, we study a number of problem variants related to service...
Article
To bridge the gap between the current practice of setting up expensive, dedicated, lightpath connections (i.e., static topologies), and the distant future vision of inexpensive access to dynamically switched end-to-end lightpaths, we propose a medium term solution in the form of edge-reconfigurable optical networks (ERONs).
Conference Paper
We present a novel architecture, which naturally enables cross-layer interactions through the construction of application-specific protocol stacks out of small reusable services which expose explicit controls to cross-layer tuning policies. Together with a concept we term `Software Defined Optics' (SDO) this architecture can enable the future optic...
Conference Paper
Full-text available
Advances in the development of large scale distributed com- puting systems such as Grids and Computing Clouds have intensifled the need for developing scheduling algorithms ca- pable of allocating multiple resources simultaneously. In principle, the required resources may be allocated by se- quentially scheduling each resource individually. However...
Article
To bridge the gap between the current practice of setting up expensive, dedicated, lightpath connections (i.e., static topologies), and the distant future vision of inexpensive access to dynamically switched end-to-end lightpaths, we propose a medium term solution in the form of edge-reconfigurable optical networks (ERONs). An ERON is an overlay-co...