IP Services Research Articles

QoS in DSL access

Which enrichments are required for the DSL architecture to transform the DSL access network from a vehicle for best effort Internet access to a multiservice platform enabling added value conversational and data services? This article details an architecture for DSL access facilitating IP service guarantees leveraging the available QoS mechanisms in the transport-technology-specific data plane, while extending the control plane. Enhanced resource and information control, policy enforcement, and advanced IP connection establishment mechanisms are key elements for the network access provider to enter the value chain for delivery of IP services.

Economics of fixed broadband access network strategies

This article presents a comprehensive techno-economic evaluation of two upgrade strategy cases for broadband IP services for residential and business customers, and illustrates their respective merits and pitfalls, allowing the definition of a reasonable investment policy. The work should enable establishment of guidelines for broadband infrastructure upgrade strategies from the incumbent operator's view. Following the definition of appropriate service sets, and taking into account demand scenarios established within the project, this work has been focused on developing a techno-economic model, based on the TONIC tool. Tariff structures have been applied to compute the key economic indicators, net present value, internal rate of return, and payback period. This investment analysis was carried using the tool, which was developed by IST-TONIC. The results show that the choice of technology (Ethernet or ATM) has almost no effect on the cost level and profitability of the cases. For the suburban area, a fiber to the cabinet solution is too expensive due to heavy infrastructure investments; for dense urban and urban areas the FTTC solution is worth the investments. The FTTH/office deployment scenario is only profitable in dense urban areas (>5000 potential customers/km <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) and already highly risky in the urban area.

Accounting and pricing: a forecast of the scenario of the next generation Internet

The Internet is becoming a multi-service network. This transformation makes it necessary to differentiate both network services and tariffs, according to the types of applications and customers' willingness to pay. Significant changes to existing architectures, procedures and protocols are necessary in order to turn the Internet into a multi-service network and a platform to develop business solutions efficiently. This evolution will favor the realization and deployment of advanced architectures to support routing, Quality of Service (QoS) provisioning, pricing, billing, accounting, and security functions. The flat-rate pricing model, commonly applied by Internet Service Providers, may become inadequate when added value IP services have to be charged. Hence, the need to define new pricing criteria, based on an appropriate combination of current usage of network resources and on the amount of the reserved resources, is expected. Other issues specifically related to these aspects are QoS-and-price based inter-domain routing, transport and content accounting models and architectures. The paper aims at introducing these problems, by describing and evaluating the solutions proposed in literature from the point of view of scalability and flexibility of market offers, and by identifying possible short-medium term trends in the field.

A method of improving misframe for HEC‐based variable length frame suitable for IP services

AbstractAs the layer 2 technology for transfer of the IP packet, a variable length frame has been proposed in which the HEC (Header Error Control) and the frame length are defined in the header. In this paper, it is shown with regard to these HEC‐based variable length frames that the phenomenon of misframing is likely, in which a hunt state appears by mistake due to frame error. As a method for improvement, a forced 2‐bit error correction method is proposed. The performance of the proposed method is clarified and the sufficient characteristic is demonstrated. In addition, from the point of view of reframe time and false frame probability, the order of the generating polynomial of CRC optimum for HEC and the backside protection stage number are presented. From a similar viewpoint, it is shown quantitatively that the error detection is superior to the error correction with regard to CRC operation in the hunt state and pre‐sync state. © 2003 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(6): 46–58, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10018

Service architectures in H.323 and SIP: A comparison

One of the major challenges for next-generation IP networks is to provide new, attractive multimedia services. This includes traditional telephony (voice over IP) and the interworking with legacy telephony systems. In addition to the general problems regarding the support of realtime services in the IP network, e.g., quality of service, voice over IP focuses on the control of advanced features such as supplementary services well known from telephony and on the mechanisms for their fast and efficient development and deployment. The two most promising approaches in the area of multimedia over IP are the protocol suites H.323 (ITU-T) and SIP (IETF). Several comparisons of these two protocols have already been published, but comparisons of their service architectures have been rarely addressed. This tutorial describes and compares the service architectures of H.323 and SIP. The basic protocol architectures are explained, followed by an in depth evaluation of the service implementation mechanisms. The analyses focus mainly on the control of telephony supplementary services in H.323 and SIP and are backed up by detailed examples. Although the two protocol architectures are quite similar, it is shown that there are considerable differences regarding their supplementary service architectures. H.323 (together with H.450) has been especially focused on supplementary services, smooth interworking with the PSTN, and interoperability between different implementations. In this respect, it has clear advantages for IP telephony applications. SIP has been designed with a broader scope, providing more generic syntax and semantics regarding feature definition and session description. Since the SIP standards do not describe details of possible application and service features, this bears the danger of interoperability problems, e.g, for supplementary services. SIP offers advantages for non voice over IP services and applications. A coexistence of both protocols can be foreseen, stressing the importance of interworking between them.

Quality-of-service in IP services over Bluetooth ad-hoc networks

Along with the development of multimedia and wireless networking technologies, mobile multimedia applications are playing more important roles in information access. Quality of Service (QoS) is a critical issue in providing guaranteed service in a low bandwidth wireless environment. To provide Bluetooth-IP services with differentiated quality requirements, a QoS-centric cascading mechanism is proposed in this paper. This innovative mechanism, composed of intra-piconet resource allocation, inter-piconet handoff and Bluetooth-IP access modules, is based on the Bluetooth Network Encapsulation Protocol (BNEP) operation scenario. From our simulations the handoff connection time for a Bluetooth device is up to 11.84 s and the maximum average transmission delay is up to 4e-05 s when seven devices join a piconet simultaneously. Increasing the queue length for the Bluetooth-IP access system will decrease the traffic loss rate by 0.02 per 1000 IP packets at the expense of a small delay performance.

ATM in MPLS-based converged core data networks

Services supported by asynchronous transfer mode account for the majority of data and Internet service revenues generated by carrier networks today. This is based on ATM's ability to support high availability services with quality of service. However, the influences of the Internet and a highly dynamic telecommunications market have raised demands for increased flexibility while controlling costs. Therefore, future carrier networks are likely to continue to be based on established technologies, such as ATM, as well as IP. In many cases, this is achieved through maintaining separate ATM and IP core networks, with the IP network supporting Internet services, while the ATM network continues to support guaranteed services such as private lines, broadband access, and video. In some cases, however, it can be advantageous for a carrier to transport segments of their ATM network over their IP network core; for example, to transport ATM traffic currently carried on leased facilities onto an IP network where the service provider owns the facilities. Developments in IP and MPLS-based traffic engineering and QoS may increase the ability of IP-based networks to support ATM services using MPLS. This article provides an overview of approaches enabling a network based on MPLS that naturally supports IP services to also support ATM services. The drivers and requirements for convergence on an IP/MPLS core network are presented, followed by an overview of the different approaches and associated challenges currently being debated in the standards bodies.

RSVP extensions for real-time services in hierarchical mobile IPv6

The Mobile IPv6 (MIPv6) provides many great features, such as sufficient addressing space, mobility, and security; MIPv6 is one of the most important protocols for next generation mobile Internet. Simultaneously, with the rapid improvement of wireless technologies, the real-time multi-media IP services such as video on demand, videoconference, interactive games, IP telephony and video IP phone will be delivered in the near future. Thus, to furnish accurate QoS for real-time services is one of the most important thing in the next generation mobile Internet. Although RSVP, which is a resource reservation protocol, processes signaling messages to establish QoS paths between senders and receivers, RSVP was originally designed for stationary networks and not aware of the mobility of MNs. Therefore, this paper proposes a novel RSVP extension to support real-time services in Hierarchical Mobile IPv6 (HMIPv6) environments. For intra-site mobility, the concept of QoS Agent (QA) is proposed to handle the RSVP QoS update messages and provide the advanced reservation models for real-time services. For inter-site mobility, IP multicast can help to invite inter-site QAs to make pre-reservation and minimize the service disruption caused by re-routing the data path during handover. Simulation results show that the proposed scheme over HMIPv6 is more suitable for real-time services than the famous RSVP tunnel-based solution.

IP QoS across multiple management domains: practical experiences from pan-European experiments

GEANT is the pan-European 10 Gbs network interconnecting European national research and educational networks (NRENs). A Premium IP service based on the DiffServ EF PHB has been specified and implemented for this environment to provide quality of service to selected user groups on a Europe-wide scale. Basic features of Premium IP are described, and results from early experiments in the production networks of GEANT and the NRENs are presented. Next steps are proposed for achieving a fast and wide availability of Premium IP in the European research networks.

QoS and SLA aspects across multiple management domains: the SEQUIN approach

The aim of this work is to define and implement an end-to-end approach to quality of service (QoS), operating across multiple management domains and exploiting a combination of link layer technologies. The architecture for the Premium IP service is presented, which aims at offering the equivalent of an end-to-end virtual leased line service at the IP layer across multiple domains. Also, the results of the initial testing performed for the validation of the service and the provisioning model for Premium IP are described. The work presented has been carried out in the framework of SEQUIN, a European Commission-funded research project.

The Flexent® packet core access platform for CDMA2000* packet data

The promise of third-generation (3G) wireless systems to the mobility industry will largely be realized through the ability to support services using high-speed packet data. When combined with full mobility, packet data services such as always-on data connections and voice over Internet protocol (VoIP) are certain to benefit and attract both end users and service providers alike. Lucent Technologies' Flexent® packet core platform has been designed to provide the performance, reliability, and flexibility to support advanced packet data services. In this paper, we describe the hardware and software architecture used to implement CDMA2000 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∗</sup> on the Flexent packet core, how it is synergistic with Lucent's existing packet data platform, and the ongoing evolution of this product to enable all IP services of the future, including VoIP.

Mobility management for VoIP service: Mobile IP vs. SIP

Wireless Internet access has gained significant attention as wireless/mobile communications and networking become widespread. The voice over IP service is likely to play a key role in the convergence of IP-based Internet and mobile cellular networks. We explore different mobility management schemes from the perspective of VoIP services, with a focus on Mobile IP and session initiation protocol. After illustrating the signaling message flows in these two protocols for diverse cases of mobility management, we propose a shadow registration concept to reduce the interdomain handoff (macro-mobility) delay in the VoIP service in mobile environments. We also analytically compute and compare the delay and disruption time for exchanging signaling messages associated with the Mobile IP and SIP-based solutions.

Mobility management in third-generation all-IP networks

It is now widely recognized that using IP as the foundation for next-generation mobile networks makes strong economic and technical sense, since it takes advantage of the ubiquitous installed IP infrastructure, capitalizes on the IETF standardization process, and benefits from both existing and emerging IP-related technologies and services. The large-scale support of data services and their integration with legacy services are the common objectives of all wireless efforts termed third generation (3G) and beyond. In these all-IP wireless networks, IP can be deployed in two modes: the transport mode and the native mode. As we show in this article, this duality in the use of IP has a significant impact on network efficiency and performance. It is the extended native use of IP in the terrestrial segment of a wireless operator's domain that more readily allows for building a converged network with multiple access technologies. We then discuss the different levels of mobility in the all-IP network. In particular, our focus is on micromobility, and on the issue of seamless localized mobility within the converged network. After reviewing the mobility schemes that have emerged in previous years, we describe a hierarchical mobility management scheme based on multiprotocol label switching (MPLS). The scheme employs an enhanced type of MPLS routers, called label edge mobility agents, and is scalable, efficient, and flexible. It directly inherits the noted capabilities of MPLS in terms of support of QoS, traffic engineering, advanced IP services, and fast restoration. This scheme does not use nodes that are specific to any given wireless technology, and is well suited for gradual deployment.

The Session Initiation Protocol: Providing advanced telephony services across the Internet

During the past few years, Internet telephony has evolved from a toy for the technically savvy to a technology that, in the not too distant future, may replace the existing circuit-switched telephone network. Supporting the widespread use of Internet telephony requires a host of standardized protocols to ensure quality of service (QoS), transport audio and video data, provide directory services, and enable signaling. Signaling protocols are of particular interest because they are the basis for advanced services such as mobility, universal numbers, multiparty conferencing, voice mail, and automatic call distribution. Two signaling protocols have emerged to fill this need: the ITU-T H.323 suite of protocols and session initiation protocol (SIP), developed by the Internet Engineering Task Force (IETF). In this paper we examine how SIP is used in Internet telephony. We present an overview of the protocol and its architecture, and describe how it can be used to provide a number of advanced services. Our discussion of some of SIP's strengths - its simplicity, scalability, extensibility, and modularity - also analyzes why these are critical components for an IP telephony signaling protocol. SIP will prove to be a valuable tool, not just for end-to-end IP services, but also for controlling existing phone services.

Implementing a management system architecture framework

Any practical vision for the evolution of communications services must include a strategy for how networking vendors make it possible for service providers to manage their networks. While the Telecommunications Management Network (TMN) framework has proponents, the IP services community has shown little interest. Furthermore, operations systems developers have long attempted to produce the best framework, but the technology is outdated before it exists. This paper addresses both issues by presenting an application-driven model for integrated management. This model can be applied to either a “classic” framework orientation or a management application view. What is common between these two views are a management portal, common data models, multiple interface technologies, open and simple network element interfaces, and common operations, administration, and administration (OA&M) tools. These are the elements for which there needs to be a consistent set of interface definitions. They form the basis for the construction of next-generation management applications.

The Lucent Technologies Softswitch-Realizing the promise of convergence

The Lucent Technologies Softswitch was created as a result of Project Saras, which was initiated by two Bell Labs researchers. The purpose of Project Saras was to develop a software system that solves several major problems that providers of telephony services now face. Today's public switched communications infrastructure consists of a variety of different networks, technologies and systems, most of which are still based on the wireline circuit-switched structure. The technology, however, is evolving to packet-based networks, and service providers need the ability to interconnect their customers with these flexible and cost-effective networks without losing the reliability, convenience, and functionality of the public switched telephone network. The Lucent Softswitch, formerly known as the PacketStar† IP Services Platform, resulted from a focus on these needs. This Softswitch was initially marketed as a signaling-interoperability and services-creation platform under the umbrella brand name PacketStar for Lucent data networking products. It was renamed in light of the recognition that it represented an emerging concept in the industry called a “softswitch,” referring to a software-based distributed switching-and-control platform. This paper provides a high-level description of the Lucent Softswitch and its application to building next-generation converged networks.

Engineering a multiservice IP backbone to support tight SLAs

This paper describes technologies that enable IP service providers to offer tighter service level agreements for IP performance, in order to create competitive advantage and better serve their customers. The SLA parameters that need to be tightened are defined and then the technologies that should be considered are described, together with the decision criteria on where each technology should be used. This paper is based upon current best practise and includes results from both lab testing and deployment experience. The specific technologies discussed are differentiated services, fast IGP convergence, and traffic engineering. Consideration is given to how these technologies should be deployed and operated.

Internet service monitoring with mobile agents

The Internet Engineering Task Force standardizes new IP technologies such as Differentiated Services and IP security that allow Internet service providers to offer new and enhanced network-level services. There is a need for a measurement infrastructure to monitor services, especially for support of end-to-end services across the Internet. The infrastructure should provide a safe way for customers to monitor the enhanced properties of the services they use. Also, providers should be able to use the infrastructure to ensure provider collaboration. We implemented a mobile-agent-based monitoring infrastructure for new and enhanced IP services.

Joint source-channel multistream coding and optical network adapter design for video over IP

We present a panorama picture on how to achieve end-to-end video over IP service under the communication environments, consisting of backbone networks, hybrid access networks, and the end users. The paper consists of three equally weighted subtopics which cover some novel thoughts in designing and implementing the video over IP system in the different areas, namely, a Synchronous Optical NETwork (SONET) network adapter for backbone connections, the joint source-channel multistream coding in hybrid access networks, and the content-based source coding in the transform domain. We propose to link the three different problems associated with the hybrid networks, which have different characteristics and design requirements, to improve the critical performances in various areas of video over IP systems. The goal is to deliver video over IP networks in more cost-effective and reliable manner. IP/ATM over SONET is currently a commonly used backbone technique. In the first part of this paper, we present a flexible design and implementation of a SONET network adapter to carry IP traffic via optical fiber. Unlike many conventional designs, our single-chip implementation supports different data rates (OC-3, OC-12, and OC-48), carries IP traffic directly over fiber, achieves more flexible for multivendor interoperability, and provides bandwidth efficient designs at the lower system latency. Hybrid access-networks via wireline or wireless connections are most likely needed for last-mile services. In the second part of this paper, we propose a joint source-channel multistream video coding scheme to combat the transmission errors under the harsh network conditions. On top of traditional error control techniques, the simulation results demonstrate that our multistream design outperform the conventional approaches by up to 5-7 dB under the harsh network conditions. To support our multistream video coding scheme, we need to access and manipulate video objects rather than the frame of pixels. In the third part of this paper, we focus on the coding of arbitrary shape video fully in the transform domain.

GMPLS-based photonic multilayer router (Hikari router) architecture: an overview of traffic engineering and signaling technology

A new extended signaling and traffic engineering method for the GMPLS-based photonic and electrical multilayer router (Hikari router) is proposed. The method allows dynamic optical network management and photonic signal recovery, such as regeneration, reshaping, etc., to be realized adaptively. Wavelength conversion is also adaptive, which reduces network cost. Multilayer traffic engineering, which yields the dynamic cooperation of IP and photonic layers, is described to provide IP services cost effectively. To realize multilayer traffic engineering, we propose the OSPF extension, which advertises both the number of total wavelengths and the number of unused wavelengths, and the RSVP-TE extension, which minimizes the number of wavelength conversions needed. In addition, this paper proposes a heuristics-based multilayer topology design scheme that uses IP traffic measurements in a generalized multi-protocol label switch (GMPLS). The proposed scheme yields the optical label switch path (OLSP) network topology, that is, OLSP placement, that minimizes network cost, in response to fluctuations in IP traffic demand. In other words, the OLSP network topology is dynamically reconfigured to match IP traffic demand. Networks are reconfigured by the proposed scheme so as to utilize network resources in the most cost effective manner.