Network Elements (network + element)

Distribution by Scientific Domains


Selected Abstracts


Ethernet aggregation and core network models for effcient and reliable IPTV services

BELL LABS TECHNICAL JOURNAL, Issue 1 2007
Christian Hermsmeyer
With the growing interest on wireline network architectures for residential triple-play and business Ethernet services there is a renewed demand for efficient and reliable packet-based transport capabilities between the content providers and the end users. Voice and data traffic carried over a variety of access technologies is collected via technology-specific access networks (e.g., digital subscriber line [xDSL], passive optical network [xPON], and wireless fidelity [WiFi]). Metro and core networks need to aggregate the various user flows from different access network nodes and provide scalable and cost-effective distribution of various flow types (e.g., Internet access, voice, video on demand, and broadcast TV services) to the relevant service access points. Varying quality of service and resiliency requirements for these services are being reflected in a new breed of converged Ethernet and optical network elements with capabilities to interwork the bearer-planes of these two networking technologies seamlessly. Network elements based on Ethernet/Optical converged technology are able to select the most fitting mechanisms from each networking technology to meet the transport requirements for each individual service demand better while providing significantly enhanced implementation and operational efficiencies. This paper discusses network architecture models and network elements addressing these goals. © 2007 Alcatel-Lucent. [source]


Distributed control of event floods in a large telecom network

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2010
Chundury Jagadish
Events in a failing system can be generated so rapidly that they adversely impact the network as well as the network management system (NMS) manager. They may fail to get delivered and critical information may get lost. This problem becomes worse in a large and congested network. Today, in practice, a management station is often flooded with a huge number of redundant events, making it difficult for the operator to process them and take corrective actions. Methods are needed to limit the volume of event transmission and number of events presented to the operator, while ensuring delivery of important information to the NMS manager. These methods need to take care of the operators' changing needs in monitoring abstraction level, for various network elements (NE) based on time and NE severity state. In this paper we propose novel techniques for distributed control of events flood, by suppressing transient events at the source. These techniques do not add any delay in communicating a failure, while ensuring that only the important events are presented to the operator. Also, the correctness of event state at the NMS is not compromised. Moreover, these methods give flexibility to the operator to dynamically change the abstraction level needed from a network element, and limit the number of events presented to the operator. The implementation of these techniques is tested with real field event traces from various telecom networks. Results show that there is a substantial reduction in the event traffic in the network. Copyright © 2009 John Wiley & Sons, Ltd. [source]


Organizational evolution of digital signal processing software development

JOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 4 2006
Susanna Pantsar-Syvšniemi
Abstract A base station, as a network element, has become an increasingly software-intensive system. Digital signal processing (DSP) software is hard real-time software that is a part of the software system needed in a base station. This article reports practical experiences related to organizing the development of embedded software in the telecommunication industry, at Nokia Networks. The article introduces the main factors influencing the development of DSP software and also compares the evolutionary process under study with both selected organizational models for a software product line and a multistage model for the software life cycle. We believe it is vitally important to formulate the organization according to the software architecture, and it is essential to have a dedicated development organization with long-term responsibility for the software. History shows that without long-term responsibility, there is no software reuse. In this paper we introduce a new organizational model for product line development. This new hybrid model clarifies long-term responsibilities in large software organizations with hundreds of staff members and formulates the organization according to the software architecture. Our case needs a couple more constraints to keep it in the evolution stage of the software life cycle. Thus, we extend the evolution phase in the multistage model to make it relevant for embedded, hard real-time software. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Phase precession and phase-locking of hippocampal pyramidal cells

HIPPOCAMPUS, Issue 3 2001
Amitabha Bose
Abstract We propose that the activity patterns of CA3 hippocampal pyramidal cells in freely running rats can be described as a temporal phenomenon, where the timing of bursts is modulated by the animal's running speed. With this hypothesis, we explain why pyramidal cells fire in specific spatial locations, and how place cells phase-precess with respect to the EEG theta rhythm for rats running on linear tracks. We are also able to explain why wheel cells phase-lock with respect to the theta rhythm for rats running in a wheel. Using biophysically minimal models of neurons, we show how the same network of neurons displays these activity patterns. The different rhythms are the result of inhibition being used in different ways by the system. The inhibition is produced by anatomically and physiologically diverse types of interneurons, whose role in controlling the firing patterns of hippocampal cells we analyze. Each firing pattern is characterized by a different set of functional relationships between network elements. Our analysis suggests a way to understand these functional relationships and transitions between them. Hippocampus 2001;11:204,215. © 2001 Wiley-Liss, Inc. [source]


Design of the ATM-based interconnecting network of the access segment of future cellular systems

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2 2001
P. P. Demestichas
Abstract An important issue in future cellular communication systems is the design of the interconnecting network of their access segment. This problem aims at finding the minimum-cost configuration of cell site switches (CSSs) and local exchanges (LEs) given the base transceiver station (BTS) layout. An extended version of the problem may also comprise the deployment of mobility and service control points-access (MSCPs-A), based on the assumption that CSSs and LEs are not fully capable of handling the logic of the cellular system. In this paper we solve the extended problem, under the additional assumption that the communication among the network elements is based on the ATM technique. The problem is formally defined, optimally formulated, and solved by computationally efficient heuristics. Finally, results are provided and subsequent conclusions are drawn. Copyright © 2001 John Wiley & Sons, Ltd. [source]


Distributed control of event floods in a large telecom network

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2010
Chundury Jagadish
Events in a failing system can be generated so rapidly that they adversely impact the network as well as the network management system (NMS) manager. They may fail to get delivered and critical information may get lost. This problem becomes worse in a large and congested network. Today, in practice, a management station is often flooded with a huge number of redundant events, making it difficult for the operator to process them and take corrective actions. Methods are needed to limit the volume of event transmission and number of events presented to the operator, while ensuring delivery of important information to the NMS manager. These methods need to take care of the operators' changing needs in monitoring abstraction level, for various network elements (NE) based on time and NE severity state. In this paper we propose novel techniques for distributed control of events flood, by suppressing transient events at the source. These techniques do not add any delay in communicating a failure, while ensuring that only the important events are presented to the operator. Also, the correctness of event state at the NMS is not compromised. Moreover, these methods give flexibility to the operator to dynamically change the abstraction level needed from a network element, and limit the number of events presented to the operator. The implementation of these techniques is tested with real field event traces from various telecom networks. Results show that there is a substantial reduction in the event traffic in the network. Copyright © 2009 John Wiley & Sons, Ltd. [source]


QoS experiences in native IPv6 networks

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 2 2009
Athanassios Liakopoulos
Deployment of IPv6 technology in research and commercial networks has accelerated in the last few years. Inevitably, as more advanced services take advantage of the new technology, IPv6 traffic gradually increases. Today, there is limited experience in the deployment of Quality of Service (QoS) for IPv6 traffic in backbone networks that support the Differentiated Services framework. As available software and hardware are designed to handle IPv4 packets, there is a need to accurately measure and validate performance of QoS mechanisms in an IPv6 environment. This paper discusses tests and technical challenges in the deployment of IPv6 QoS in core networks, namely the production dual stack gigabit-speed Greek Research and Education Network (GRNET) and the IPv6-only 6NET European test network, using both hardware and software platforms. In either case, we succeeded in delivering advanced transport services to IPv6 traffic and provided different performance guarantees to portions of traffic. The deployed QoS schema was common to IPv6 and IPv4; in most cases both v4 and v6 traffic exhibited comparable performance per class, while imposing no significantly different overhead on network elements. A major conclusion of our tests is that the IPv6 QoS mechanisms are efficiently supported with state-of-the-art router cards at gigabit speeds. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Benefits and costs of transport Classification, methodologies and policies

PAPERS IN REGIONAL SCIENCE, Issue 2 2001
T.R. Lakshmanan
Transport; benefits; costs; evaluation Abstract. This article aims to bring together insights from a broad body of recent literature concerned with the nature, the measurement and policy implications of benefits and costs of transport. It is argued that, for various reasons, transport cannot be treated as an,ordinary'economic sector, and the policy implications of a number of the sector's peculiarities are addressed. Explicit attention is given to spatial aspects and network elements, internal and external benefits and costs, and efficiency aspects and equity considerations in policy making. [source]


Network modules help the identification of key transport routes, signaling pathways in cellular and other networks

ANNALEN DER PHYSIK, Issue 12 2009
R. Palotai
Abstract Complex systems are successfully reduced to interacting elements via the network concept. Transport plays a key role in the survival of networks , for example the specialized signaling cascades of cellular networks filter noise and efficiently adapt the network structure to new stimuli. However, our general understanding of transport mechanisms and signaling pathways in complex systems is yet limited. Here we summarize the key network structures involved in transport, list the solutions available to overloaded systems for relaxing their load and outline a possible method for the computational determination of signaling pathways. We highlight that in addition to hubs, bridges and the network skeleton, the overlapping modular structure is also essential in network transport. Path-lenghts in the module-space of the yeast protein-protein interaction network indicated that module-based paths may cross fewer modular boundaries than shortest paths. Moreover, by locating network elements in the space of overlapping network modules and evaluating their distance in this ,module space', it may be possible to approximate signaling pathways computationally, which, in turn could serve the identification of signaling pathways of complex systems. Our model may be applicable in a wide range of fields including traffic control or drug design. [source]


Semantic networking: Flow-based, traffic-aware, and self-managed networking

BELL LABS TECHNICAL JOURNAL, Issue 2 2009
Ludovic Noirie
In order to overcome current Internet limitations on overall network scalability and complexity, we introduce a new paradigm of semantic networking for the networks of the future, which brings together flow-based networking, traffic awareness, and self-management concepts to deliver plug-and-play networks. The natural traffic granularity is the flow between packet and circuit and between connection-less and connection-oriented modes. Using flow aggregation capabilities, we simplify traffic processing in the nodes through elastic fluid switching, and simplify traffic control through flow admission control, policing, and implicit quality of service (QoS) routing. By leveraging deep packet inspection and behavioral traffic analysis, network elements can autonomously and efficiently process the traffic flows they transport through real-time awareness gained via semantic analysis. The global consistency of node decisions within the whole network is ensured by self-management, applying the concepts of "knowledge plane" and "network mining." © 2009 Alcatel-Lucent. [source]


Converged network common charging controller function

BELL LABS TECHNICAL JOURNAL, Issue 2 2008
Xiang Yang Li
With the emergence of converged networks, circuit switched (CS), packet switched (PS), and IP Multimedia Subsystem (IMS) domains and application servers (AS) are now merging to combine all kinds of services, business modes, and network architectures. This can cause chaos among various charging mechanisms within the networks. This paper presents a common charging controller function (CCCF) between the charging trigger function (CTF) of individual network elements (NEs) and the charging system. The CCCF operates with the common NE-independent charging control layer to serve various network elements in CS, PS, and IMS domains and application servers. It also simplifies NE-dependent CTFs for accounting metrics collection (AMC), regardless of whether the charging mechanisms are online or offline. The CCCF maintains a single charging characteristic database that stores the charging mechanism of each subscriber's service usage and forwards subscriber accounting data to the charging systems. By including the CCCF in networks, the IMS and pre-IMS charging systems for existing and new customers can be integrated without replacing deployed products, resulting in significant cost savings for telecommunications vendors and customers. © 2008 Alcatel-Lucent. [source]


End-to-end diagnostics in IPTV architectures

BELL LABS TECHNICAL JOURNAL, Issue 1 2008
Kamakshi Sridhar
The introduction of new revenue-generating services like Internet Protocol television (IPTV) promises to bring to the end user a much more personal-ized communication and entertainment experience at an affordable cost. IPTV brings new features like video on demand (VoD), broadcast TV, and customized ad insertion, along with more traditional voice and data services whose realization requires a wholesale deployment of existing and new protocols and new network elements. Configuration, maintenance and troubleshooting of such networks, customized for each end user, are complex, and it is widely believed that providing diagnostics mechanisms is of substantial importance for rollout of IPTV. This paper describes research efforts at Alcatel-Lucent toward the definition and development of end-to-end diagnostics for IPTV architectures, comprising probes and mechanisms to detect problems in the network and to issue corrective measures. © 2008 Alcatel-Lucent. [source]


Ethernet aggregation and core network models for effcient and reliable IPTV services

BELL LABS TECHNICAL JOURNAL, Issue 1 2007
Christian Hermsmeyer
With the growing interest on wireline network architectures for residential triple-play and business Ethernet services there is a renewed demand for efficient and reliable packet-based transport capabilities between the content providers and the end users. Voice and data traffic carried over a variety of access technologies is collected via technology-specific access networks (e.g., digital subscriber line [xDSL], passive optical network [xPON], and wireless fidelity [WiFi]). Metro and core networks need to aggregate the various user flows from different access network nodes and provide scalable and cost-effective distribution of various flow types (e.g., Internet access, voice, video on demand, and broadcast TV services) to the relevant service access points. Varying quality of service and resiliency requirements for these services are being reflected in a new breed of converged Ethernet and optical network elements with capabilities to interwork the bearer-planes of these two networking technologies seamlessly. Network elements based on Ethernet/Optical converged technology are able to select the most fitting mechanisms from each networking technology to meet the transport requirements for each individual service demand better while providing significantly enhanced implementation and operational efficiencies. This paper discusses network architecture models and network elements addressing these goals. © 2007 Alcatel-Lucent. [source]


SIP message prioritization and its applications

BELL LABS TECHNICAL JOURNAL, Issue 1 2006
Harold Batteram
Session Initiation Protocol (SIP) signaling is an integral part of the IP Multimedia Subsystem (IMS) to support services such as Voice over IP (VoIP), multimedia sessions, presence, and instant messaging (IM). All of these services share a common SIP signaling infrastructure. In spite of careful network engineering, SIP network elements may experience high-load situations, in which SIP messages may experience too much delay or even get dropped. This paper addresses how such undesired high-load situations can be handled effectively by introducing a message prioritization mechanism in SIP servers. To validate the mechanism, it has been implemented in a highperformance JAIN*-SIP-compliant Java* SIP stack. This SIP stack incorporates several other innovations, such as a very efficient SIP message parser, and it can be used for a variety of SIP-based applications. Its design enables service providers to define custom message prioritization and rejection strategies based on SIP message characteristics, system state, and statistics. Measurements show that high-priority emergency messages can indeed be serviced without significant delay or loss in a high-load situation. The concept of and techniques for SIP prioritization are the subjects of a Lucent Technologies patent application. © 2006 Lucent Technologies Inc. [source]


Session initiation protocol services architecture

BELL LABS TECHNICAL JOURNAL, Issue 1 2002
Janet R. Dianda
The session initiation protocol (SIP) is a unifying protocol for providing integrated telephony and Internet types of services, such as Web, presence, instant messaging, and chat. To provide for the integration of these disparate types of services, considerations must be given from a network point of view. However, little attention has been given in the literature to identify the network elements required to provide these services or the mechanisms for integrating these different types of services for end users. This paper describes a network-level services architecture for SIP, including network functions and entities needed to support the services integration. We will discuss how services can be incorporated at different levels in the network, and the types of services typically created at each of these levels. We will also describe a service access and mediation function, which blends disparate types of services in creating a seamless and rewarding user experience. © 2002 Lucent Technologies Inc. [source]


Middleboxes: Controllable media firewalls

BELL LABS TECHNICAL JOURNAL, Issue 1 2002
Paul Sijben
Internet technology is promised for the broadband multi-service future. However, it is unclear how this technology can bring service providers the needed revenue, since today this technology cannot provide basic quality guarantees for the services rendered. Generally, over-provisioning of the bandwidth is used to get the services to an acceptable level, but this is costly and cannot work in areas where high aggregation rates are necessary (such as the local loop). Today IP (router) technology lacks mechanisms for high-granularity access control, per-user accounting, and quality of service (QoS) policing. We believe that, for a service provider to deploy billable services, these issues need to be resolved. Only if access to the service is controlled and only when the network provides information about the usage of the network elements can next-generation services in the telecommunication industry, like voice over IP (VoIP) and multimedia conferencing, be rolled out profitably. In this paper, we present a technology that can address these needs. We employ controllable firewalls that have the ability to prevent unwanted IP traffic from entering a network. Creating pinholes that allow individual calls (voice or real-time multimedia streams) in controllable firewalls can be done very fast and efficiently. Traditional firewalls have no such provisioning. Multiple application servers should be able to request pinholes to one or more controllable firewalls. This approach, while familiar from the public switched telephone network (PSTN), is a new paradigm for IP networks. © 2002 Lucent Technologies Inc. [source]


Splitting the Baby: An Empirical Test of Rules of Thumb in Regulatory Price Setting

KYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 3 2005
T. Randolph Beard
Summary This article provides an empirical evaluation of a recent and important exercise in regulatory price setting in the United States. The 1996 Telecommunications Act required incumbent local phone companies to sell components of their network to rival firms at regulated prices, and the prices for these ,unbundled network elements' were based primarily on independent estimates of forward-looking economic costs. Our econometric analysis reveals that, while cost is a primary determinant of element prices, the prices also reflect foregone retail profits for incumbent firms. Statistical tests suggest that ,splitting the baby' is an accurate positivist description of public agency behavior. [source]