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Buffer sizing is an important network configuration parameter that impacts the quality of service characteristics of data traffic. With falling memory costs and the fallacy that "more is better," network devices are being overprovisioned with large buffers. This may increase queueing delays experienced by a packet and subsequently impact stability of core protocols such as TCP. The problem has been studied extensively for wired networks. However, there is little work addressing the unique challenges of wireless environments such as time-varying channel capacity, variable packet inter-service time, and packet aggregation, among others. In this article we discuss these challenges, classify the current state-of-the-art solutions, discuss their limitations, and provide directions for future research in the area. [ABSTRACT FROM PUBLISHER]

Wireless sensor networks with mobile sinks, mWSNs, have attracted a lot of attention recently. This is because sink mobility can greatly alleviate the hotspot issue in WSNs and further prolong the network lifetime. However, sink mobility also causes unexpected changes in network topology and data routing paths, which can largely affect the routing performance in such networks. Design of efficient routing protocols for mWSNs has been a critical issue, and much work has been carried out in this aspect. In this article, we first classify existing protocols based on different design criteria and then present a survey of the state-of-the-art routing protocols in this area. We illustrate how each of the protocols works, and discuss their advantages and disadvantages. Finally, we point out some future directions for efficient routing in mWSNs. [ABSTRACT FROM AUTHOR]

Policy-based management allows the deployment of networks offering quality services in environments beyond the reach of real-time human control. A policy-based protocol stack middleware, the context-aware broker, has been developed by the authors to autonomically manage the remote deep space network. In this article example policy rules demonstrate the concept, and prototype results from ns-2.30 show the overall positive costbenefit impact in an example scenario. [ABSTRACT FROM AUTHOR]

The recent advances in wireless client devices and the crucial role of multimedia communications in our society have motivated relevant standardization efforts, such as the IP multimedia subsystem, to support session control, mobility, and interoperability in all-IP next-generation networks. IMS has already driven the design of commercial mobile multimedia, but exhibits limited support for service continuity during handoffs. In particular, it omits advanced techniques to reduce/eliminate handoff delays, especially during vertical handoffs (i.e., change of the wireless technology employed by a client to access the wired Internet, e.g., from UMTS to WiFi). We propose an original solution for session continuity based on the primary design guideline of cleanly and effectively separating the signaling plane (for session reconfiguration via SIP) from the media delivery plane (data transmission and related handoff management operations). Our optimized handoff management techniques exploit terminal-based decentralized predictions to minimize service-level handoff delays. Different from other recent related work, our proposal fully complies with the standard IMS infrastructure and works at the application level. The reported experimental results point out that our solution, available as an open source tool for the IMS community, reduces playout interruption times relevantly by introducing a limited and scalable signaling overhead. [ABSTRACT FROM AUTHOR]

This article investigates distributed cooperative medium access control protocol design for multihop wireless networks. Cooperative communication has been proposed recently as an effective way to mitigate channel impairments. With cooperation, single-antenna mobile terminals in a multi-user environment share antennas from other mobiles to generate a virtual multiple-antenna system that achieves more reliable communication with a higher diversity gain. However, more mobiles conscribed for one communication inevitably induces complex medium access interactions, especially in multihop wireless ad hoc networks. To improve the network throughput and diversity gain simultaneously, we investigate the issues and challenges in designing an efficient MAC scheme for such networks. Furthermore, based on the IEEE 802.11 DCF, a cross-layer designed cooperative MAC protocol is proposed. The MAC scheme adapts to the channel condition and payload length. [ABSTRACT FROM AUTHOR]

Recent studies demonstrated that dynamic spectrum access can improve spectrum utilization significantly by allowing secondary unlicensed users to dynamically share the spectrum that is not used by the primary licensed users. Cognitive radio was proposed to promote the spectrum utilization by opportunistically exploiting the existence of spectrum "holes." Meanwhile, cooperative relay technology is regarded widely as a key technology for increasing transmission diversity gain in various types of wireless networks, including cognitive radio networks. In this article, we first give a brief overview of the envisioned applications of: cooperative relay technology to CRNs, cooperative transmission of primary traffic by secondary users, cooperative transmission between secondary nodes to improve spatial diversity, and cooperative relay between secondary nodes to improve spectrum diversity. As the latter is a new direction, in this article we focus on this scenario and investigate a simple wireless network, where a spectrum-rich node is selected as the relay node to improve the performance between the source and the destination. With the introduction of cooperative relay, many unique problems should be considered, especially the issue for relay selection and spectrum allocation. To demonstrate the feasibility and performance of cooperative relay for cognitive radio, a new MAC protocol was proposed and implemented in a universal software radio peripheral-based testbed. Experimental results show that the throughput of the whole system is greatly increased by exploiting the benefit of cooperative relay. [ABSTRACT FROM AUTHOR]

As Ethernet traffic increases rapidly in carrier networks, service providers have an increasing need for Ethernet infrastructure networking in order to scale their Ethernet services. Ethernet infrastructure transports Ethernet traffic over distance, protects the traffic from link and nodal failures, and aggregates Ethernet connections from a large number of low-speed ports onto a much smaller number of high-speed ports. An Ethernet infrastructure allows service providers to inexpensively interconnect end user locations with one another for private line services, and to interconnect end users with the VPLS and IP/MPLS service edges for enterprise, residential, and mobility services. OAM and protection capabilities are critical to enable Ethernet to be deployed as an infrastructure technology. This article reviews several important developments in Ethernet OAM and protection standards, and discusses how those capabilities are vital for the creation of an effective Ethernet infrastructure. [ABSTRACT FROM AUTHOR]

In this article, a novel network architecture called resilient burst ring is proposed to implement the next-generation WDM-supported ultrahigh-speed (100 gigabit or higher) carrier Ethernet. This architecture inherits all the best features of resilient packet ring (IEEE 802.17), provides a burst-mode data transmission scheme through a two-sublayer (optical and electronic) hierarchy, and realizes the WDM-supported ultra-high-speed Ethernet with scalability and reliability. RBR adopts a two-layer buffering scheme to resolve the contentions of optical burst packets and provides three different data transmission modes. With the proposed PriorityOnly-Destination-Delay resource reservation control protocol, RBR can provide a flexible Q0S strategy to implement the transmission of all of the applications and services in existing networks. [ABSTRACT FROM AUTHOR]

As data rates outpace the capabilities of electronic encryption schemes, photonic layer security may fill the gap in providing a communication security solution at high data rates. In this article we review and highlight the advantages of our proposed optical code-division multiplexed (OCDM)-based photonic layer security (PLS) system based on high-resolution control of the optical phase of tightly spaced phase locked laser lines. Such a PLS system is scaleable to 100 Gb/s and provides a protocol independent security solution. We review the use of high-resolution control of the optical phase of mode-locked laser frequency combs as an enabling technology for a new class of OCDM systems. A network based on such systems is compatible with and can have comparable spectral efficiency to existing DWDM networks. Through inverse multiplexing of 10 Gb/s tributaries, we have already demonstrated optical transmission of a 40 Gb/s aggregate OCDM signal over 400 km. Such a PLS solution is achieved through shared phase scrambling of the individual OCDM codes assigned to each of the tributaries using an integrated micro-ring resonator-based phase coder/scrambler. The confidentiality of OCDM-based PLS is robust against exhaustive, known plain text, and archival/forensic attacks, and can complement digital encryption operating at higher layers. Moreover, the integrity of the PLS solution is ensured through the inherent coupling to confidentiality, since knowledge of the key is needed in order to easily alter the transmitted data stream without introducing observable errors. This system can leverage advances in optical integration to support new applications where electronic encryption is impractical because of space, weight, power, availability, and cost requirements. Such applications range from timely security support for the emerging 100 GbE standards to all-optical multilevel security offered through the compatibility of PLS with transparent DWDM networks. [ABSTRACT FROM AUTHOR]

Enterprises are increasingly using Ethernet as the foundation for transforming their networks to Internet Protocol. Simultaneously, service providers are deploying Ethernet to exploit the demand for wide-area Ethernet services and as the infrastructure for new residential services. such as IPTV. This is due to Ethernet's low cost per bit and ubiquity in local area networks. Recent years have seen the widespread deployment of IP/MPLS networks to address this opportunity. IP/MPLS enables enhanced flexibility over the same converged network for IP and legacy services, avoiding the need to build separate per-service networks. It also adds carrier-grade capabilities such as quality of service, traffic engineering, and resiliency, thereby enabling new multipoint services such as virtual private LAN service. However, using Ethernet for "always-on" and other mission-critical services has resulted in new resiliency requirements, in both the access and the network core. Two novel developments address these high expectations by enabling significant improvements in service availability. These are pseudowire redundancy and Ethernet multi-chassis link aggregation. This article reviews the current redundancy mechanisms typically deployed in Ethernet and MPLS networks. We show how additional enhancements are required in both the network core and the access to the Ethernet service. We describe new pseudowire redundancy and MC-LAG mechanisms, showing how they work together to enable end-to-end protection for Ethernet virtual private wire services and VPLS. [ABSTRACT FROM AUTHOR]

Giving the operator the ability to manage in-home devices greatly increases the potential of the cost-efficient provision of new profitable services. In this spirit, standardization undertaken by the DSL forum not only addresses remote management of the residential gateway but recently, also extends to in-house devices. We propose a solution that bridges remote management specified by CWMP with UPnP, already established inside the home environment. This approach will enable providers to remotely configure and manage in-house UPnP-enabled equipment, thus accelerating the deployment of new services. We investigate the nature of the two protocols and specify the bridging functionality, taking into consideration scalability and transparency. Experimental results support the applicability of the proposed approach, highlight the importance of message filtering, and provide general insight into the interplay intricacies of the particular protocol functions. [ABSTRACT FROM AUTHOR]

As communications networks become increasingly dynamic, heterogeneous, less reliable, and larger in scale, it becomes difficult, if not impossible, to effectively manage these networks using traditional approaches that rely on human monitoring and intervention to ensure they operate within desired bounds. Researchers and practitioners are pursuing the vision of autonomic network management, which we view as the capability of network entities to self-govern their behavior within the constraints of business goals that the network as a whole seeks to achieve. However, applying autonomic principles to network management is challenging for a number of reasons, including: • A means is required to enable business rules to determine the set of resources and/or services to be provided. • Contextual changes in the network must be sensed and interpreted, because new management policies may be required when context changes. • As context changes, it may be necessary to adapt the management control loops that are used to ensure that system functionality adapts to meet changing user requirements, business goals, and environmental conditions. • A means is required to verify modeled data and to add new data dynamically so that the system can learn and reason about itself and its environment. This article provides an introduction to the FOCALE autonomic network management architecture, which is designed to address these challenges. [ABSTRACT FROM AUTHOR]

The home gateway market is undergoing deep changes. On one side, home networks are evolving, getting dynamic and federating more and more devices. On the WAN side, new actors appear, such as multimedia content providers. From both sides emerge new features and new management needs. In this article we highlight challenges and benefits of moving more intelligence to the home gateway, making it more than a simple interconnection device. We argue that we need a full-fledged execution environment on gateways to address the evolution of business models. We present this evolution and summarize existing solutions for execution environments and management for home gateways. Then we propose two improvements that reflect the new requirements. The first improvement is a high-level virtualization of service gateways, and the second one recommends an end-to-end dynamic multiprovider management system. [ABSTRACT FROM AUTHOR]

Although network management has always played a key role for industry, it only recently received a similar level of attention from many research communities, accelerated by funding opportunities from new initiatives, including the FP7 Program in Europe and GENI/FIND in the United States. Work is ongoing to assess the state of the art and identify the challenges for future research in the field, and this article contributes to this discussion. It presents major findings from a two-day workshop organized jointly by the IRTF/NMRG and the EMANICS Network of Excellence, at which researchers, operators, vendors, and technology developers discussed the research directions to be pursued over the next five years. The workshop identified several topic areas, including management architectures, distributed real-time monitoring, data analysis and visualization, ontologies, economic aspects of management, uncertainty and probabilistic approaches, as well as understanding the behavior of managed systems. [ABSTRACT FROM AUTHOR]

In this article we study two representative mobility management schemes for mobile hotspots with heterogeneous multihop wireless links: the NEMO basic support protocol at the network layer and the SIP-based network mobility support protocol at the application layer. We evaluate their salient features and quantify their handoff latency. It is shown that the SIP-based network mobility support protocol can easily be deployed and reduce the tunneling overhead incurred in the NEMO basic support protocol. However, it increases handoff latency due to longer message length. We also discuss several open research issues for seamless mobility support in mobile hotspots. [ABSTRACT FROM AUTHOR]

The trend toward the integration of current and emerging applications and services in the Internet has launched new challenges regarding service deployment and management. Within service management, admission control has been recognized as a convenient mechanism to keep services under controlled load and ensure the required QoS levels, bringing consistency to the services offered. In this context, this article discusses the role of AC in multiservice IP networks, and surveys current and representative AC approaches. We address and compare the architectural principles of these AC approaches and their main features, virtues, and limitations that have an impact on the quality control of network services. We identify important design aspects that contribute to the successful deployment of flexible and scalable AC solutions in multiservice networks. [ABSTRACT FROM AUTHOR]

The 3GPP specifies the IP multimedia subsystem (IMS) to provide several kinds of multimedia services in UMTS Release 5 and later releases. Interworking at the service layer between 3GPP and Wimax networks requires interworking between IMS functionality. By studying several interconnection scenarios and the main functionality of IMS, this article analyzes how the interworking of 3GPP and Wimax networks can be performed to support different levels of service interconnection. Special attention is paid to the interconnection at the session negotiation level, using SIP (the base protocol of the IMS), COPS/Go, and Diameter protocols/interface to provide session negotiation with QoS and AAA (authentication authorization accounting) support. [ABSTRACT FROM AUTHOR]

The present view of medical environments, where isolated networks are used for IT and medical applications, is changing toward an integrated heterogeneous network scenario that can support a wide range of applications. WPAN and WLAN technologies will play a fundamental role in enabling such integrated environment that is expected to support both medical and nonmedical applications. The ultimate goal is to exploit WPAN and WLAN technologies, as well as other wireless networks, such as 3G cellular systems and satellite networks, to support highly efficient medical care delivery, anytime and anywhere. However, the life-critical nature of some medical applications imposes additional challenges that have not been considered in nonmedical scenarios. This article discusses some future scenarios where WLAN and WPAN technologies can be used to provide an integrated and ubiquitous network in medical environments, and identifies the main issues to be addressed in order to meet the QoS requirements of different medical applications when operating in integrated environment. [ABSTRACT FROM AUTHOR]

With the Information Age in full and rapid development, users are becoming accustomed to having immediate access to information. Users demand more capabilities from every kind of electronic device: more processing power, more features, and better connectivity. Users are also realizing the benefits of collaborating with others in their communities to help expand the body of knowledge. One user that understands the benefits of information sharing is the United States Department of Defense. The DoD's Network-Centric Enterprise Services initiative, along with the concept of pushing the ‘power to the edge,’ aims to enable end users with maximum situational awareness and the most comprehensive battlespace, all in a secure networking environment. Providing so much data and capabilities to the end user, however, will require an increase in communications capability and efficiency. To address increased capability needs, the DoD is continually developing and enhancing the Global Information Grid (GIG) throughout its various ‘layers’ of communication infrastructure. One such layer of infrastructure involves the use of cooperative low Earth orbiting satellites for efficient multicasting communications. In this article we review the network-centric concept and the GIG infrastructure. We then discuss the potential benefits to adding a low Earth orbit satellite communications infrastructure to the GIG model. Finally, we show how multicasting protocols can enhance the efficiency within the GIG and reduce some of the long-haul communications burdens. [ABSTRACT FROM AUTHOR]

This article reports the latest results of an R&D effort to develop a prototype implementation of a dynamic policy-based network management (PBNM) system that can be used to configure and manage a secure network for a coalition environment across an unsecured wide area network. The prototype, based on a distributed architecture, includes capabilities for policy creation and management, dynamic policy negotiation, and dynamic policy provisioning. The policy negotiation facilitates the rapid deployment of a coalition network while the dynamic policy provisioning automates the configuration and management of network services including firewalls, virtual private network connections, routing, quality of service (QoS), and domain name services. Such a PBNM system enhances an organization's ability to react to network incidents identified by a network situational awareness assessment. Although the focus of the current research is a military coalition environment, the system can be used in any distributed enterprise or collaborative environment. [ABSTRACT FROM AUTHOR]

The need for openness in mobile handset platform architectures from an applications development perspective, with a conflicting need for closedness in such platform architectures for security, manageability, and multiprotocol communications processing, has created a need for an overall platform architecture that provides simultaneous support for such features. Platform architectures are suggested that are rooted in hardware along with a trusted platform-aware architecture manager that creates closed partitions to provide cryptographic, communications, and manageability services, as well as open partitions for applications processing. Important and desirable ingredients in such platform architectures include domain separation, hardware rooted mechanisms to establish platform trust, hierarchical key management, secure storage, efficient resource management, and an inherently manageable platform. [ABSTRACT FROM AUTHOR]

In the previous article [1], via experimental studies, we have analyzed the performance of a TCP/IP layered architecture in multihop ad hoc networks. The experimental results point out that a legacy protocol stack does not operate efficiently in ad hoc networks, and cross layering is a promising approach to improve the performance. Cross layering opens a second phase in the ad hoc network design. In this article we present the cross-layer architecture and related protocols, developed in the MobileMAN project. By implementing a full prototype of this architecture, we show that it significantly outperforms a legacy TCP/IP layered architecture. [ABSTRACT FROM AUTHOR]

In this article we present the details of a generalized multi-protocol label switching controlled wavelength-division multiplexing (WDM) optical network developed under the Optical Network Focused Interest Group (ONFIG) program in Singapore. The WDM network is controlled through a GMPLS control plane that consists of CR-LDP, LMP, and OSPF-TE. We conducted various field trials on the GMPLS-capable WDM optical network testbed with the main focus on distributed storage service application. We developed and evaluated a distributed storage services application on the WDM optical network testbed and demonstrated that incorporating a lightweight data transport protocol with optical network control could be an efficient approach for data-intensive storage applications by exploiting the dynamic connection establishment and backup protection features. [ABSTRACT FROM AUTHOR]

The recently developed H.264 video standard achieves efficient encoding over a bandwidth ranging from a few kilobits per second to several megabits per second. Hence, transporting H.264 video is expected to be an important component of many wireless multimedia services, such as video conferencing, real-time network gaming, and TV broadcasting. However, due to wireless channel characteristics and lack of QoS support, the basic 802.11-based channel access procedure is merely sufficient to deliver non-real-time traffic. The delivery should be augmented by appropriate mechanisms to better consider different QoS requirements and ultimately adjust the medium access parameters to the video data content characteristics. In this article we address H.264 wireless video transmission over IEEE 802.11 WLAN by proposing a robust cross-layer architecture that leverages the inherent H.264 error resilience tools (i.e., data partitioning); and the existing QoS-based IEEE 802.11e MAC protocol possibilities. The performances of the proposed architecture are extensively investigated by simulations. Results obtained indicate that compared to 802.11 and 802.11e, our cross-layer architecture allows graceful video degradation while minimizing the mean packet loss and end-to-end delays. [ABSTRACT FROM AUTHOR]

Applications using traditional protocol stacks (e.g., TCP/IP) from wired networks do not function efficiently in mobile wireless environments. This is primarily due to the layered architecture and implementation of protocol stacks. One mechanism to improve the efficiency of the stack is cross-layer feedback, that is, making information from within one layer available to another layer of the stack. For example, TCP retransmissions can be reduced by making it aware of network disconnections or handoff events. We highlight the need for a cross-layer feedback architecture and identify key design goals for an architecture. We present our ECLAIR architecture, which satisfies these design goals. We describe a prototype implementation that validates ECLAIR. We also discuss other cross-layer architectures and provide a cross-layer design guide. [ABSTRACT FROM AUTHOR]

The dynamic nature of ad hoc networks makes system design a challenging task. Mobile ad hoc networks suffer from severe performance problems due to the shared, interference-prone, and unreliable medium. Routes can be unstable due to mobility and energy can be a limiting factor for typical devices such as PDAs, mobile phones, and sensor nodes. In such environments cross-layer architectures are a promising new approach, as they can adapt protocol behavior to changing networking conditions. This article introduces CrossTalk, a cross-layer architecture that aims at achieving global objectives with local behavior. It further compares CrossTalk with other cross-layer architectures proposed. Finally, it analyzes the quality of the information provided by the architecture and presents a reference application to demonstrate the effectiveness of the general approach. [ABSTRACT FROM AUTHOR]

In this article we propose cross-layer design frameworks for 802.16e OFDMA systems that are compatible with WiBro based on various kinds of cross-layer protocols for performance improvement: a cross-layer adaptation frame- work and a design example of primitives for cross-layer operation between its MAC and PRY layers. In addition, we provide a simulation framework for cross-layer analysis between the MAC and PRY layers in 802.16e systems. Through this cross-layer simulator, we show that average cell throughput can be improved by 25-60 percent by applying careful cross-layer adaptation schemes. [ABSTRACT FROM AUTHOR]

This article presents a brief overview, state of the art, and taxonomy of optical WDM testbeds, and outlines the differences between them and the ADRENALINE testbed. ADRENALINE is an optical circuit-switched WDM testbed that deploys reconfigurable OADMs based on various technologies (e.g., AWO and tunable lasers). In ADRENALINE, end-to-end lightpaths are set up and torn down dynamically and in real time by means of a GMPLS-based control plane (switched connections) and a distributed management plane (soft-permanent connections). ADRENALINE supports the request of SPCs under user initiative by combining GMPLS, SNMP, and XML. ADRENALINE allows both the topology and major characteristics of the data communications network to be modified, enabling control and management related experiments with varying DCN. In our experiments we investigate user management of lightpaths and address its performance in terms of basic SLA parameters related to connection establishment (delay and availability). Finally, we address remaining challenges and outline exciting avenues of future work on ADRENALINE. [ABSTRACT FROM AUTHOR]

This article describes OAM in MPLS layer 2 transport networks. MPLS networks used to transport layer 2 traffic are referred to as MPLS layer 2 transport networks. They may be used to connect legacy layer 2 networks and/or provide layer 2 service to a user over a MPLS network. As legacy layer 2 networks migrate to use MPLS for transport, the role of MPLS OAM mechanisms is becoming increasingly important. This is because the converged network must offer the same OAM functionality as existing layer 2 networks. This article emphasizes the importance of end-to-end OAM, while emulating existing layer 2 services using MPLS transport. End-to-end fault detection is described in the context of various layer 2 over MPLS transport network models. The article focuses on state-of-the-art MPLS label switched path and pseudo wire OAM mechanisms being developed by the IETF. This includes fault detection and isolation mechanisms such as LSP-Ping, bidirectional forwarding detection, and virtual circuit connectivity verification. The applicability of each of these mechanisms is given. In some cases it may be possible to carry layer 2 OAM cells end-to-end, while in other cases this may not be possible. The relationship between segment-based OAM mechanisms and end-to-end OAM is described for each of these cases. [ABSTRACT FROM AUTHOR]

This article provides an overview of AT&T's MPLS OAM architecture, and gives examples of operational experience. Hallmarks of the architecture are a single, converged, and integrated MPLS/optical network, and the evolution to fully automated, zero-touch network operation. The Concept of One converged IPIMPLS architecture will reduce operations, development, and capital costs. The Concept of Zero aims to bring full automation for every human-to-computer interaction currently required for setting up and maintaining network services, delivering services to customers in real time with zero defects and cycle time, and supporting both a network as well as an operational environment with six nines reliability. This approach effectively opens the network to the customer, enabling new levels of customer network management, service creation, and ordering, and empowering enterprise customers with the tools to create their own network services as they transform their own internal networks. In the article we describe AT&T's MPLS-enabled services, the corresponding MPLS operations architecture (including MPLS MIBs), our MPLS OAM operational experience, and MPLS OAM evolution needs for MPLS MIB enhancements and new network capabilities. By applying technologies such as artificial intelligence, self-healing/self-identifying network elements, expert systems, rules-based processes, and automatic speech recognition, the architecture will migrate from a predictive network that monitors, correlates, and recommends action; to an adaptive network that monitors, correlates, and takes action; to a cybernated network that has integrated components that dynamically manage by business rules and policies. We give several examples of how AT&T is already investing in and implementing this future vision, and conclude by challenging network researchers, developers, and key industry players to apply new technologies in fully realizing the operational vision. [ABSTRACT FROM AUTHOR]

The boundaries between packet and circuit networks have long disappeared, with many traditional circuit-switched applications such as voice and video now being carried over packet-switched IP/MPLS or Ethernet networks. However, this transition has happened so fast that many OAM functions supported by circuit-switched networks such as SONET/SDH are still unmatched in packet networks. In order to match the quality sustained by circuit-switched networks, OAM functions must also be developed for such packet networks. A number of recent efforts have started to address OAM functions for IP/MPLS and Ethernet packet technologies. Service providers and carriers alike are the driving force behind the work, as there is general recognition that to generate sustained revenues, services must be efficiently managed. In this article we discuss issues in providing OAM features and capabilities for MPLS-based packet networks. [ABSTRACT FROM AUTHOR]

The emerging next-generation networking environment presents an IP-based core interconnecting many wireless radio access networks, providing ubiquitous access to end users through a vast variety of wireless devices. Although the IP protocol will be the common denominator, the new environment brings together many different interconnecting domains, each following different QoS models, complicating the overall end-to-end QoS process. This article discusses the need to standardize an end-to-end QoS protocol. It does not, however, focus on the signaling mechanism, since there is currently a relevant ongoing activity in IETF. Instead, it concentrates on the formulation of the QoS information describing the QoS requirements of the session to be established. It presents the Generic Service Specification Framework that not only enables the QoS requirements of a specific session to be captured (like a generic QoS template), but also the QoS classes of each IP domain can be described according to it. Through the systematic specification of a domain's QoS classes, an intelligent automatic mapping algorithm can be applied during an end-to-end QoS request, in order to select the most appropriate service class in each domain, as well as to extract the required traffic-related parameters to perform traffic con- trol operations, such as admission control, policing, and scheduling. [ABSTRACT FROM AUTHOR]

We present a novel end-to-end QoS architecture that enables seamless services over heterogeneous wireless access networks. We discuss the main architectural approaches and design issues of mobility-aware QoS signaling in IP networks. then we introduces a QoS signaling architecture that integrates resource management. It is based on a domain resource manager concept and nicely supports various handover types in an integrated approach. In particular, we support anticipated handover with pre-reservation of resources over the old network before the mobile node is attached to the new access point. [ABSTRACT FROM AUTHOR]

The Stream Control Transmission Protocol (SCTP) is being standardized by the IETF as a reliable transport protocol to transport SS7 signaling messages over IP networks. Due to its attractive features such as multistreaming and multihoming, SCTP has received much attention from the network community, in terms of both research and development. This article introduces the main features of SCTP, and discusses the state of the art in SCTP research and development activities. We also provide a survey of the available products that use SCTP. Finally, with a view to stimulating further research in this area, the challenges faced by the SCTP research community are identified. [ABSTRACT FROM AUTHOR]

Several solutions are proposed to extend storage area networking solutions over distances of hundreds to thousands of kilometers. Native Fibre Channel or end-to-end Fibre-Channel-based solutions can be offered over long distances using SONET-based networks. Protocols such as Internet SCSI (iSCSI), Internet Fibre Channel Protocol (iFCP) and Fibre Channel over TCP-IP (PCIP) are being proposed to enable storage area networking solutions over networks that use IP as their transport protocol. Performance analysis of these solutions in terms of application throughput under variable network conditions of packet loss, bandwidth availability, extension distance, and TCP implementations in the sender and receiver is presented based on analytical modeling of different solutions. [ABSTRACT FROM AUTHOR]

Over the last decade, the tremendous growth in the mobile Internet user population has been accompanied by an equally exciting evolution in wireless data networks. However, quite understandably, the evolution has been distinctly characterized by an increasing degree of heterogeneity along several dimensions such as the access technology, network model, device, and application requirements. This heterogeneity, in turn, imposes a significant challenge on the design of the network protocol stack, and leads to the question: how can the protocol stack at a mobile host cater effectively to the heterogeneous characteristics of the operating environment? In this article we provide an overview of AdaptNet, an adaptive protocol suite for next-generation wireless data networks. AdaptNet consists of protocol solutions at different layers of the protocol stack addressing several problems, including rate adaptation, congestion control, mobility support, and coding. A common traderlying theme in the design of the protocols in the AdaptNet suite is adaptiveness to the operating environment. Through high-level discussions, preliminary results, and pointers to relevant related work, we show how AdaptNet achieves the goal of effectively addressing heterogeneity in next-generation wireless data networks. [ABSTRACT FROM AUTHOR]

Many new Internet applications require data transmission from a sender to multiple receivers. Unfortunately, the IP multicast technology used today suffers from scalability problems, especially when used for small and sparse groups. Multicast for small conferences (MSC) is a novel approach aimed at providing more efficient support for audio conferences, for example. It makes use of an IPv6 routing header. The unicast addresses of a small receiver group are put into the extension header in order to be forwarded to all group members. The results indicate that MSC has the potential to replace IP multicast for many delay-sensitive small group applications, even with very limited support from the network infrastructure. [ABSTRACT FROM AUTHOR]

Describes the reliable multicast protocol in computer networks. Characteristics which distinguish it from earlier computer network protocols; Guarantee of delivery and ordering of the messages from the sources; Reformation protocol that reorganizes the broadcast group and guarantees the consistency of message sequences.

SONET/SDH systems have been the preferred transport technology over fiber optics for almost two decades now. Carriers have developed extensive expertise in operating, managing, and developing business models for these systems. Manufacturers' technical expertise in such systems has increased to a deep understanding of what transport over fiber is about. In short, SONET/SDH can be called a mature transport technology. Out of this mature expertise, new techniques for bettering transport over fiber services have appeared. These techniques are likely to considerably reshape the next generation of SONET/SDH systems in many aspects: new transport techniques, new transport services, new management systems and business models. We describe several new transport techniques, and discuss their impact on the creation of new transport services for next-generation SONET/SDH systems [ABSTRACT FROM PUBLISHER]

Evaluates three routing protocols with INSIGNIA, an in-band signaling system that supported adaptive reservation-based services in mobile ad hoc networks. Overview of the INSIGNIA signaling systems; Discussion on the simulation environment used; Transmission control protocol performance.

Examines the impact of streaming traffic on transmission control protocol (TCP) performance. Approaches to mitigate the negative impacts of streaming media traffic on Web traffic; Available bit rate service; Investigation of the unfairness problem that occurs when TCP flows compete among themselves.

This article presents information about the papers published in the "Cross-Layer Protocol Engineering for Wireless Mobile Networks" section of the December 2005 issue of the "IEEE Communications Magazine." The rapid evolution of the next generation wireless network is being driven by the growth of wireless packet data applications. One of the challenges in this evolution is to develop end-to-end protocol solutions across networks by using IP technologies. Cross-layer protocol engineering is an emerging research area and it also holds potential for comprehensive results addressing relevant issues to support emerging applications. The first article, "Cross-Layer Design: A Survey and the Road Ahead," presents information about cross-layer design proposals and also presents classification of the initial proposals for cross-layer interaction implementations. The second article "Cross-Layer Design for Resource Allocation in 3G Wireless Networks and Beyond" focuses on different cross-layer design approaches for resource allocation in 3G CDMA networks. Another article "Utility-Based Resource Allocation and Scheduling in OFDM-Based Wireless Broadband Networks" focuses on resources management in broadband wireless networks.

Quality of service (QoS) has been a frequently used term and hot research topic in the past few years. However, IP networks and wireless cellular systems have been looking at QoS provisioning from rather different perspectives. In IP and computer networks, researchers mainly concentrated on those techniques that could enable migrating traditional best effort Internet service with no guarantee on delay or throughput or even reliable delivery of packets into a more predictable architecture. Differentiated services, integrated services, and various combinations of the two techniques have tried fulfilling QoS in the Internet by defining different architectures and reservation techniques. While research on these and other alternative techniques is still ongoing, due to the large-scale architecture of the global Internet and the diversity in Internet nodes, routers, and hosts, Internet QoS still has a long way to go to become a reality. One implication issue in providing QoS over the Inter net, arising from the fact that QoS should be maintained on an end-to-end basis, is that without a mutual commitment from all intermediate links and networks, is that QoS cannot be guaranteed. Such commitment is even difficult for a small private network, not to mention for the widespread Internet where each packet may travel on a different path from other packets of the same message. For cellular systems, traditionally service quality has been guaranteed for certain measures, including call dropping probability, call blocking probability, security, and, more important for voice communications, delay limits. With the introduction of data services, cellular providers have tried to accommodate a certain level of service guarantee to data transactions, mainly those that used the traditional circuit-switched network to deliver data packets.

The move to Internet Protocol (IP)-based content delivery services has challenged the television industry by allowing high-quality television content to be delivered using the Internet, wired and wireless, private and public. The new convergence paradigm is already playing out its disruptive role as ?television? is now associated with both a personal and social experience using an ecosystem of devices. The unidirectional flow of content from an operator to a device has thus morphed into a much richer combination of real-time on-demand web and user generated content complementing traditional programming. [ABSTRACT FROM AUTHOR]

The article focuses on ad hoc and sensor networks and highlights the papers that are published in the current issue of "IEEE Communications Magazine" to present information on the sensor networks. Certain aspects of sensor networks such as adaptively configurable protocols and distributed computation are relatively a new one. The information pertaining to these new aspects of sensor networks is presented in the current issue of the magazine. It includes a mix of more traditional as well as novel research problems and solution directions in sensor and ad hoc networks.

Anritsu Co., unveiled at Supercomm the MP159OB network performance tester, the first single test instrument capable of conducting Ethernet over SONET/SDH (EoS), Ethernet/IP, Virtual Concatenation, 0Th, and SONET/SDH tests. Designed to meet the needs of next generation optical networks and network elements such as switches and routers, the MP159OB provides unique simultaneous analysis on multiple interfaces up to 10.7G. This means, for example, that the MPI59OB can perform full 0Th, SONET, or EoS analysis on one interface while analyzing the same or different data on one or more Ethernet/IP interfaces. The MP159OB can perform all major EoS tests, including Generic Framing Procedure, Local Area Network Extension Protocol for PPP, and Link Access Procedure. In an EoS application, for example, the network performance tester can check encapsulation functions and throughput via simultaneous operation on Ethernet and SONET/GFP links while checking errors/alarms of both links utilizing 15 GFP counters, 40+ SONET/SDFI counters, and 60+ Ethernet/IP counters. MPI59OB can test virtual concatenation and the Link Capacity Adjustment Scheme protocol as well.