Communication networks and specifically the Internet have emerged as a source of empowerment in today’s society. At a global level, the Internet is increasingly becoming the backbone of the modern economy and society to the extent that the new generations in developed countries cannot even conceive of a world without broadband access to the Internet.
Although the Internet has successfully enabled multiple waves of innovation, novel societal and commercial uses are continuing to push the original Internet architecture to its limits. Unforeseen and extremely popular applications, such as Skype, YouTube, and the BBC iPlayer, have sprung up and steered the use of the Internet into directions that had not been anticipated at its origin. In addition, the enormous increase in online content and the requirement of providing universal access to broadband Internet services is already stretching the capabilities of current technologies to their limit.
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. New applications require networks with well-known and predictable characteristics and behavior, which the current best-effort Internet intrinsically cannot deliver. These considerations are triggering network models that can potentially transform the established technology content and business models of the Internet. New global initiatives (http://www.future-internet.eu/, http://www.geni.net/, http://akari-project.nict.go.jp/eng/conceptdesign.htm) are aimed at rethinking and rebuilding the Internet considering novel technical approaches, sometimes called “clean slate,” which advocate a radical redesign or change of paradigms in the long term. These new efforts to create the “Future Internet” rely on strategic, multidisciplinary research on new Internet concepts, including “disruptive” approaches.
There are many challenges seen as driving forces towards the Future Internet. Some of these challenges are the ones listed below:
The available bandwidth per user/device will continue to grow: Dial-up has been completely replaced in most countries with broadband connections. The expected wide deployment of optical access networks and fiber-to-the-home (FTTH) solutions will further increase the bandwidth capabilities at the edges of the Internet enabling Gb/s delivery to the user. The routing and transport schemes in the existing Internet will not scale to the Gb/s transmission rates that will be made available to future applications
Heavy increase in content and quality of content: There will be an enormous increase in online content offered by the Future Internet. Digital photos and videos will not only increase in number, but also in size, due to increases in resolution and the ease of creation and manipulation. As the quality of media content increases, the demand to provide and sustain a high quality of service (QoS) also increases proportionally. Processing, transmission, and presentation errors that were acceptable at lower resolutions become intolerable in high-definition and ultra-high-definition (HD/UHD) video. For such high-quality content, distribution over IP “best-effort” networks is not possible without a substantial deterioration of the QoS.
Huge increase in the number of users: Much like the growth of telephony in the 20th century, the number of Internet users will continue to increase as the digital divide narrows in various countries. Furthermore with the increased Internet availability and security, business communities move towards the use of Internet via secure virtual private network (VPN) solutions rather than private data networks. Therefore we expect that the use of the Internet will continue to accelerate at an exponential level. However, the addressing and routing schemes in the existing Internet will not scale to the tens of billions of users predicted to use the Future Internet.
Large data flow transfers between users, remote instrumentation, and computing/data centers: Several new applications require transfer of very large data flows between users and/or data centers. Examples include financial, e-science, content distribution, and large remote sensor and instrumentation applications, which appear to generate large data flows that need to be delivered to computing/storage centers that can be far away. Furthermore, Moore’s law will continue to drive the need for higher bandwidth connectivity through the increase of the computational power (teraflops) and memory (terabytes) of devices. Solutions such as grid and cloud computing have identified that for the Internet to support these applications, it is important to enable dynamic high-bandwidth secure services over a physical (L1/L2) infrastructure.
Energy-efficient networking: Recently there is increasing attention on energy saving in telecommunication networks. Although today the total energy consumption of the Internet is very small compared with the levels of power consumption required by other industries, it is rapidly expanding and is predicted to become an important contributor. The power consumed by large routers is increasing with their overall capacity increase and has become one of the most stringent limits in the design of IP routers. The expected increase of line rates to will further stress these limits. It is important to identify switching technologies, architectures, and protocols to minimize network power consumption. Optical technologies offer significant advantages with respect to power consumption when information is transmitted and/or switched at increasing bit rates and at longer distances.
The above challenges are seen as fundamental areas where advanced optical technologies could provide effective solutions and drive the development of the Future Internet. For example, it is generally agreed that supporting Gb/s transmission rates to the end users for applications such as grid and cloud computing, digital cinema, and ultra-high-definition digital broadcast requires the employment of alternative (rather than current IP) network infrastructure. Solutions need to satisfy several challenging network design and operational requirements such as the dynamic allocation of network resources (including lightpaths), multicasting, effective integration of multiple Layer1, Layer2 with Layer3 operations, edge device addressing, and new mechanisms for network management and control. In addition, Layer1 and Layer 2 services supported by underlying optical technologies can play a significant role in greening telecommunication infrastructures.
This special issue of the Journal of Optical Communications and Networking has attracted many submissions and includes a number of high-quality papers discussing the most significant aspects that will position optical technologies as a fundamental contributor in defining the Future Internet architecture. The published papers cover a wide spectrum of topics associated with optical networks in the context of the Future Internet to address the challenges described above. More specifically, the following research areas are explored:
- Control plane,
- Virtualization of optical network infrastructures,
- Optical access networks.
Several papers deal with the role of the Control Plane in optical networks in the context of the Future Internet. One of the invited papers concentrates on application-driven control of network resources in multiservice optical networks. It introduces the service concept in the optical network context and proposes and validates a service platform for application-driven resource management in a GMPLS-controlled optical network. A second paper concentrates on the design and implementation of a GMPLS-controlled grooming-capable transport infrastructure that introduces the operation of a GMPLS-controlled multilayer network architecture, with implementation-related data collected through the ASON/GMPLS CARISMA testbed. A third paper applying a general control-delay representation provides a study to quantify the effect of signaling on routing performance and evaluates the effect of outdated information for a wide interval of control delay values on a set of routing scenarios. A fourth paper focuses on the resilience of emerging-generation GMPLS networks and proposes a traffic engineering scheme that uses virtual preemption and configurable survivability to improve the resilience of the emerging generation GMPLS networks. A fifth paper proposes the extension of the backwards recursive path computation algorithm and the path computation element (PCE) protocol to address the end-to-end wavelength continuity constraint in wavelength-switched optical networks. The performance of the solution has been evaluated in a GMPLS-controlled network of the ADRENALINE testbed. A sixth paper addresses a Future Internet infrastructure based on the transparent integration of access and core optical transport networks with the aim to overcome the limitations of segmentation of networks and domains. An integrated control plane for optical access and core networks is proposed and evaluated. One of the invited papers addresses deterministic Internet services requiring advance reservation of network resources and focuses on an integrated design for provisioning of sliding scheduled services over WDM optical networks jointly performing the scheduling and routing and wavelength assignment of the demands. Furthermore, the routing in optical networks in the context of the Future Internet has been addressed by this special issue. One paper focuses on lightpath- and light-tree-based groupcast routing and wavelength assignment in mesh optical networks and evaluates its performance. Two papers deal with resilience in optical networks. One paper focuses on online partitioning for scalable and survivable optical networks and proposes a dynamic and distributed technique that forms clusters adaptively in response to the current network conditions, e.g., node connectivity, bandwidth availability (or traffic load), and shared risk link groups. The second paper proposes a protection scheme for single-duct ring networks followed by a rearrangeable bandwidth allocation scheme and dual-duct rings for improved efficiency of network resource utilization and signal quality.
Virtualization of optical network infrastructures is also addressed by this special issue. One invited paper focuses on virtualizing and scheduling optical network infrastructures for emerging IT services. It proposes a service framework to offer Internet service providers dynamic access to virtual private execution infrastructures through on-demand and in-advance bandwidth and resource reservation services. A second invited paper on infrastructure services for optical networks presents techniques for virtualizing and managing optical networks. Moreover, the “Infrastructure as a Service” (IaaS) concept, allowing deployment of dynamic services in optical networks and federation of their underlying infrastructures, has been described. One contributed paper experimentally demonstrates how the virtual private LAN service technique can improve optical network performance in terms of quality of service. Another contributed paper describes how optical OFDMA technologies can facilitate the Future Internet with emphasis on network virtualization mechanisms, programmable network architectures, parallelism of optical transmission, and guaranteed quality of service provisioning. Another contributed paper addresses the requirement for novel service composition mechanisms suitable for the Future Internet. In this context it proposes a service plane architecture facilitating the interconnection of heterogeneous optical networks, IT resources, and requestors of services and presents mechanisms, models, and algorithms to facilitate this.
The role of optical technology in the scope of the Future Internet is also addressed. One of the invited papers provides a detailed overview of optical networking technologies able to create bandwidth-abundant future networks responding to the inefficiencies of current IP technologies, in particular the energy consumption and throughput limitations of IP routers. Optical burst switched (OBS) solutions and approaches are also covered by two papers in this special issue. One paper focuses on constraint-based anycasting in OBS networks. It proposes a mathematical framework to support anycast delivery accounting for quality-of-service parameters such as resource availability, reliability, propagation delay, and quality of transmission. A second paper investigates the design of MAC protocols for tunable transmitter-tunable receiver-based WDM burst-switched ring networks utilizing token rings. A number of papers address optical packet switching (OPS). More specifically, one paper discusses quality-of-service support in optical packet switches in the context of high-speed multiservice networking foreseeable for the Future Internet. Another paper focuses on even slot transmission in slotted optical packet switched networks and proposes four basic metrics and three hybrid metrics to achieve an even slot transmission from an ingress switch of a multiwavelength/fiber slotted OPS network. A third paper proposes a dual-layer congestion control scheme for TCP carried by optical packet switching with UDP background traffic for use when transporting Internet traffic over optical packet switched networks. The topic of multigranularity optical networks is addressed through a paper presenting a relevant blocking probability model considering three granularity levels (fiber, waveband, and wavelength) aiming at reducing the cost and size of the switch fabric.
Two papers address optical access networks and technologies in the context of the Future Internet. More specifically one paper addresses the issue of high bandwidth requirements for Future Internet services and proposes a hybrid ring-shaped wavelength division multiplexing/time division multiplexing passive optical network that is capable of providing bandwidth on demand at high bit rates in a transparent and dynamic manner. The second paper focuses on fair resource distribution within a WDMA/TDMA optical access network based on a GPON infrastructure. This work includes design of algorithms for efficient bandwidth allocation in the time and wavelength domains and reports relevant results.
Lena Wosinska, Associate Editor
Dimitra E. Simeonidou, Guest Editor
Anna Tzanakaki, Guest Editor
Carla Raffaelli, Guest Editor
Christina Politi, Guest Editor