Bandwidth Pipes Research Articles

Light-Trail Design for 5G Backhaul: Architecture, SDN Impact and Coordinated Multipoint

5G promises to be revolutionary from the perspective of offering unprecedented bandwidth to the end user. In this pursuit, the limited spectrum of the wireless overlay, further constricted by distance, requires strong support from a backhaul network. Such a strong backhaul network should provide large bandwidth pipes with near proximity to the end user at low costs and using pragmatic technology. Naturally, an optical solution is best suited to meet the voluminous bandwidth requirements of the backhaul. This optical solution has to cater to dynamic bandwidth needs among base stations and provide rapid and smart provisioning to meet the requirement of new features such as Coordinated Multipoint (CoMP) among base stations, and yet be low cost. To this end, we propose the use of light-trails (LTs), which are a generalization of a lightpath that provides for dynamic bandwidth communication, sub-wavelength optical grooming and optical layer multicasting using contemporary optics. We observe that each feature of a LT, i.e., dynamic provisioning, optical multicast, and sub-wavelength grooming is strongly desired by the 5G backhaul, implying a clear mapping between them. We investigate the usage of light-trails as a 5G backhaul solution. We discuss the proposed architecture of light-trails for micro cells, pico cells, and femto cells. We present the LT design problem for 5G backhaul as a constrained optimization problem. We also present a mechanism to achieve coordinated multipoint using light-trails. A dynamic virtual topology growth algorithm for the backhaul is also presented and extensively evaluated. The light-trails approach is compared to other approaches, the use of an SDN controller is discussed and significant performance benefits are observed.

An adaptive inter-domain PCE framework to improve resource utilization and reduce inter-domain signaling

Upcoming broadband commercial and scientific applications are now demanding high bandwidth pipes across multiple domains with guaranteed Quality of Service (QoS). Recent research initiatives such as the Path Computation Element (PCE) framework are focusing on the development of scalable multi-domain QoS provisioning frameworks, especially within the emerging carrier grade transport technologies based on layer-2 tunnels. QoS provisioning across multiple domains requires that QoS parameters for available transit paths inside a domain be advertised in the inter-domain routing algorithms, while the dynamic inter- and intra-domain connections vary the available resource, and hence require frequent inter-domain updates. The signaling load on the other hand hampers the scalability of the inter-domain routing mechanisms. We propose the use of an adaptive partitioning framework, which can effectively use network resources and at the same time stabilize the advertised domain topologies and thus path advertisements. Our method partitions network resources by pre-reserving resources for inter-domain transit traffic, and uses policies to modify the resource partitioning in order to maintain the available transit capacity between specified bounds. We show by simulations that the proposed mechanism can reduce inter-domain signaling load by 10%–20% and reduce overall blocking inside a domain by creating a trade-off between available resources for intra-domain connections and inter-domain transit connections. The reduction in inter-domain signaling and blocking can be used as a building block to design scalable QoS routing systems for carrier grade transport networks.

CHEETAH virtual label switching router for dynamic provisioning in IP optical networks

Enabling new IP-based services such as triple and quad-play, as well as eScience applications at predetermined quality of service (QoS) measures, require the provisioning of guaranteed bandwidth pipes at varying granularities (e.g. from few Mbps to several Gbps and above). Dynamic provisioning of bandwidth pipes, whereby a connection is dynamically setup and released upon signalling, is a cost-effective method of enabling such services. Dynamic provisioning is a new paradigm in network control and management (NC&M) that requires the introduction of control plane (i.e. routing and signaling) capabilities within network elements such as routers, layer 2 switches and layer 1 cross-connects. In this paper we share our experience in the design and deployment of a Generalized Multiple Protocol Label Switching (GMPLS) control plane for layer 2 switches in the experimental Circuit-Switched High-Speed End-to-End Transport Architecture (CHEETAH). We call this software engine CHEETAH Virtual Label Switching Router (CVLSR). CVLSR allows non-GMPLS devices (e.g. Ethernet switches, routers and other cross-connects) to participate in the dynamic provisioning of end-to-end bandwidth-guaranteed connections. It extends the dynamic provisioning of connections to the end-users across different administrative domains. We have successfully deployed the CVLSR in CHEETAH optical network across HOPI/DRAGON network. The interoperability of the CVLSR with commercial GMPLS SONET-based cross-connect switches has been demonstrated.

A cross-layer optical circuit provisioning framework for data intensive IP end hosts

Using circuit-switched optical networks for next generation e-science applications is gaining increasing interest. In such applications, circuits are provisioned for end hosts to accomplish data-intensive or QoS-stringent communication tasks. Existing provisioning methods provide point-to-point connectivity for end hosts, that is, an established circuit connects one end host to another, and during the lifetime of the circuit, only communication tasks between the connected end hosts can be served. This inhibits circuits from being used in more general cases, where each end host communicates with different remote parities simultaneously through a single network interface. We propose V-STONES - a data flow-based VLAN tagging and switching technique to increase the connectivity of end host network interfaces in circuit-switched networks. With V-STONES, not only can an IP end host communicate with different remote systems concurrently through bandwidth guaranteed connections, but also protocol entities at different stack layers can talk to their counterparts through dedicated bandwidth pipes. In this article, we review the existing circuit provisioning methods and then discuss V-STONES and the architecture of cross-layer circuit provisioning for end hosts. We also introduce a prototype implementation in an optical network testbed and present the experimental results.

Algorithmic aspects of bandwidth trading

We study algorithmic problems that are motivated by bandwidth trading in next-generation networks. Typically, bandwidth trading involves sellers (e.g., network operators) interested in selling bandwidth pipes that offer to buyers a guaranteed level of service for a specified time interval. The buyers (e.g., bandwidth brokers) are looking to procure bandwidth pipes to satisfy the reservation requests of end-users (e.g., Internet subscribers). Depending on what is available in the bandwidth exchange, the goal of a buyer is to either spend the least amount of money so as to satisfy all the reservations made by its customers, or to maximize its revenue from whatever reservations can be satisfied. We model this as a real-time nonpreemptive scheduling problem in which machine types correspond to bandwidth pipes and jobs correspond to end-user reservation requests. Each job specifies a time interval during which it must be processed, and a set of machine types on which it can be executed. If necessary, multiple machines of a given type may be allocated, but each must be paid for. Finally, each job has associated with it a revenue, which is realized if the job is scheduled on some machine. There are two versions of the problem that we consider. In the cost minimization version, the goal is to minimize the total cost incurred for scheduling all jobs, and in the revenue maximization version the goal is to maximize the revenue of the jobs that are scheduled for processing on a given set of machines. We consider several variants of the problems that arise in practical scenarios, and provide constant factor approximations.

Single-Layer Optical Platform Based on WDM/TDM Multiple Access for Large-Scale “Switchless” Networks

The European Union ACTS project SONATA will define and demonstrate a cswitchlessn all-optical network to provide a future single-layer, advanced transport architecture on a national scale. The single-hop, shared-access network employs time and wavelength agility (a WDMA/TDMA protocol), using fast tunable transmitters and receivers to route individual customer connections as well as bandwidth pipes through a single wavelength router (suitably replicated for resilience). No electronic switching nodes or cross-connects (telephony, IP, ATM, SDH) are required within the transport network, nor optical cross-connects (save the wavelength routing node), thus providing major transport architecture simplifications and hardware reductions. The network is scalable to 200 Tbit/s throughput over 1, 000 krn, connecting 20 million terminals operating at 622 Mbit/s over 50.000-way split c<hyperPONss, by means of 800 WDM channels with 0.05 nm channel spacing (6.25 GHz). Details of network dimensioning, physical layer modeling and network control issues are presented.

The impact of voice processing on modern telecommunications

Research has been conducted in the area of voice processing for over six decades but it has only been in the past few years that the impact of the years of research is starting to be seen in modern telecommunications systems. Virtually every area of voice processing, including speech coding, speech synthesis, speech recognition, and even, to a small extent, speaker verification, has left the research laboratory and now appears in a product or service that is in daily use out in the marketplace, often by millions of customers per day. This revolution in voice processing in telecommunications is fueled by algorithmic advances (which improve the quality of the voice processing systems), hardware advances (which provide high processing power and memory at low cost), and networking advances (which provide high bandwidth pipes to the home, office, and throughout the telecommunications network). In this paper we illustrate the impact of voice processing on modern telecommunications by showing the diverse ways in which speech coding, speech synthesis, speech recognition and speaker verification have become embodied in new products and services.

Sunshine: a high performance self-routing broadband packet switch architecture

The authors present a high-performance self-routing packet switch architecture, called Sunshine, that can support a wide range of services having diverse performance objectives and traffic characteristics. Sunshine is based on Batcher-banyan networks and achieves high performance by utilizing both internal and output queuing techniques within a single architecture. This queuing strategy results in an extremely robust and efficient architecture suitable for a wide range of services. An enhanced architecture allowing the bandwidth from an arbitrary set of transmission links to be aggregated into trunk groups to create high bandwidth pipes is also presented. Trunk groups appear as a single logical port on the switch and can be used to increase the efficiency of the switch in an extremely bursty environment or to increase the access bandwidth for selected high-bandwidth terminations. Simulation results are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>