| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 74-80 |
| Abstraksi Narasi | : | ATM is a widespread technology adopted by many operators to support advanced data communication, in particular efficient Internet services provision. The expected challenges of multimedia urgently require redesign of network of networking solutions in terms of both new functionalities and enhanced performance. However, the networking context is affected by so many changes, and to some extent chaotic growth, that any approach based on a structured and complex too-down architecture is unlikely to be applicable. Instead, and approach based on finding out the best match between realistic service requirements and the pragmatics, intelligent use of technical opportunities made available by the product market seems more appropriate. By following this approach, innovations and improvements can be introduced at different times, not necessarily complying with each other according to a coherent overall design. With the aim of pursuing feasible innovations in the different networking aspects, at CSELT we are investigating a few of the most crucial topics related to the IP and ATM integration perspective. In particular, we are developing reserach concerning efficient multicasting for conferences and TV over the net, service integration and quality control, as well as high performance and enhanced routing. After a brief survey of the state of the art, the article reports the most significant results so far achieved by CSELT in advanced networking with the aim of contributing to focus further enhancements in the direction of broadening the range of supported services. With reference to multicasting, the article illustrates field experience managing complex. MBone conference configurations over ATM and preliminary laboratory results dealing with IP/ATM integrated multicasting. In the service integration area, measurements are illustrated concerning RSVP over ATM that show the benefits of resources allocation for QoS support when different traffic types are mixed. Integration of IP and ATM is then discussed by inroducing experimental results able to improve the routing and switching capabilities, starting from the many solutions currently proposed at the internationsl level. From this point of view, a significant investigation area is the introduction of a `feature programmability` function within network elements, in order to augment service flexibility. Enhanced routing is illustrated as an example of programmable features that will be feasible with advanced networking platforms. |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 110-111 |
| Abstraksi Narasi | : | - |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 50-65 |
| Abstraksi Narasi | : | In recent years the Internet has developed into a global data network that highly accepted as a multimedia information platform which has the potential to develop into an alternative carrier network in the future. Telecom operators increasingly act as Internet service providers to maximize network utilization, to attract or retain customers, and to generate additional revenue. To leverage their installed nbase in the PSTN/ISDN the optimal strategy for telco ISPs is the integration of their point of presence into the central office: packetizing and grooming of IP traffic in the local office relieves load on the PTSN/ISDN trunk network, resolves existing bottlenecks due to Internet traffic upstream of the CO, and creates new opportunities for revenue-generating features for both telephony and Internet suscribers. This article intends to shows that current telecommunication network elements can be upgraded with innovative cutting-edge technology to build a solid basis for a seamless multimedia network of tomorrow, thereby enabling telecom operators` and service providers` tremendous investment in existing network infrastructur to be fully utilized. An integrated Internet services platform is presented which turns the CO switch into an optimized link between the PSTN/ISDN and the Internet. Technically, it is proposed that the central office be expanded with an integrated Internet Pop (IPOP) configured from the following IP components: an internal high-speed data backbone (ATM or Ethernet); modem pools to terminate dial-in calls from analog modems using the PPP protocol; protocol handlers for UDP, TCP, IP, and lower-layer data protocols (X.25, frame relay, SDMS, etc); access to data networks; IP router, RADIUS server, and name server database; a contents server (optionally), enabling telco ISPs to become content providers. This effectively turns the CO into an Internet access point that integrates smoothly into the existing telco OA&M/TMN. Investment in additional hardware is minimized, and the existing subscriber line and network infrastructure is completely reused. The IP functions integrated in the IPOP can interwork closely with PSTN/ISDN call processing. This is prerequisite for the creation of new revenue-generating features such as supplementary PSTN/ISDN services for Internet calls, voice over IP, IP-activated dialing, and value-added Internet services (on-screen call-waiting indication, near-real-time bill viewing, etc). As the demand for high-bandwidth subscriber access increases, existing line concentrators can be upgraded with wideband line cards. High-bandwidth IP traffic may be groomed in the concentrator and multiplexed directly on the high-speed (ATM, Ethernet) backbone network. The great benefit of an integrated approach is that the evolution from lower to higher bandwidth is smooth and as the market requires, thus guaranteeing the balance between necessary investment and revenue. This integrated approach is illustrated in this article by means of a concrete example using a state-of-the art CO switch. |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 66-73 |
| Abstraksi Narasi | : | In response to the explosive increase in the number of mobile subscribers and the ever stronger demand for mobile multimedia service, the authors propose introducing the ATM techniwue for next-generation mobile network infrastructures in order to handle a high volume of traffic and develop multimedia communications. First, this article clarifies mobile-specific requirements for and advantages of applying ATM to mobile infrastructure networks. However, it is risky for network operators en bloc to replace the conventional STM-based infrastructure by ATM. Therefore, this article shows a smooth evolution path for the mobile network infrastructure to convert from conventional STM to ATM s mobile multimedia services mature. Even in future mobile networks, the main traffic may still be voice communications, whose bit rate is too low for efficient use of the radio frequency band. Applying ATM to such vey-low-bit-rate mobile voice streams is inefficient due to the delay in filling out the pay-load of an ATM cell; this `packetization delay` degrades the quality of service. This problem can be solved by using a layered cell structure for the mobile ATM network. This cell structure enebles the efficient transfer of voice signals ranging from very-low-bit-rate signals to high-speed multimedia signals with little delay. Standardization of this cell structure is progressing in ITU-T and the ATM Forum. Transmission efficiency is estimated here by simulation. |
| Nama Pengarang | : | Anders Rockstrom, Bengt Zdebel, Hiroshi Nakamura et al, Ulrich Schoen et al, Mostafa Hashem Sherif, Eugenio Guarene, Paolo Fasano, Vinicio Vercellone, Maarten van Steen et al, Katia Obraczka, Sian Morgan, Philip Dumortier, Uwe Briem et al, Stephen Paul Benson |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 36-40 |
| Abstraksi Narasi | : | The telecom business is due for fundamental changes, concerning both technology and enterprise-but also concerning attitudes. This article discusses the merger between telecom and datacom, the business and technological trends-in order outline future architecture for service and infrastructure. Our approach is that the causes of change are more fundamental than is normally conceived. Today the telecom community focuses on deregulation and competition, rather than observing that there will be different types of traffic dominating our networks-businesses. We also tend to focus on broadband technology, rather than observing that the emerging services require online properties and a connectionless network. Our own attitude, to interpret new phenomena in telecommunications concepts, disable us from using new technology and understanding new business. An overall conclusion is, in sweeping terms, that our operations in the future will be dominated by datacom networks rather than telecom networks. This, in turn, requires a new scenario for interoperability and regulation-and calls for new business models. It is argued that the focus for regulations should beinteroperability rather than infrastructure. Furthermore, a generic `hour-glass` architecture is sketched-assuming, for example, IP as the interoperability level separating the megabits per second market from the service market. The discussion in this article reflect one strand of srategic discourse on future networks within Telis and other Euorepan operators. |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 112-116 |
| Abstraksi Narasi | : | In this article, the authors describe recent activities of telecommunication and information standardization organizations, such as the ITU-T, ISO/IEC JTC1, and ISO/IEC, related to multimedia communications. Recent achievements of the related fora and consortia, such as the ATM Forum, IETF, and DAVIC, which play important roles in standardizing multimedia applications, are also described. |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 82-89 |
| Abstraksi Narasi | : | Traffic models are at the heart of any performance evaluation of telecommunications networks. An accurate estimation of network performance is critical for the success of broadband networks. such networks need to guarantee an acceptable quality of service (QoS) level to the users. Therefore traffic models need to be accurate and able to capture the statistical characteristic of the actual traffic. In this article we survey and examine traffic models that are currently used in the literature. Traditional short-range and non-traditional long-range dependent traffic models area presented. Number of parameters needed, parameter estimation, analytical tractability, and ability of traffic models to capture marginal distribution and auto-correlation structure of actual traffic are discussed. |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 30-43 |
| Abstraksi Narasi | : | Satellite ATM networks have significant advantages over terrestrial ATM networks. Satellites provides unique advantages such as remote coverage with rapid deployment, distance insensitivity, bandwidth on demand, immunity to terrestrial disasters, and offering broadband links. Satellite ATM networks will play an important role in the rapidly evolving information infrastructure. However, there are several obstacles which need to be overcome so that satellite ATM networks can operate in full service. The objective of this survey is to present the state of the art in satellite ATM networks and to point out open research problems. |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 102-109 |
| Abstraksi Narasi | : | In Part I of this tutorial, the major elements that contribute to fading and their effects in a communication channel were characterized. Here, in Part II, these phenomena are briefly summarized, and emphasis is then placed on methods to cope with these degradation effects. Two particular mitigation techniques are examines: the Viterbi equalizer implemented in the Global System for Mobile Communication (GSM), and the Rake receiver used in CDMA systems built to meet Interim Standar 95 (IS-95). |
| Nama Pengarang | : | - |
| Nama Majalah/Jurnal | : | IEEE Communications Magazine |
| Volume / Nomor Edisi | : | - |
| Nomor Halaman | : | 90-100 |
| Abstraksi Narasi | : | When the mechanisms of fading channels were first modeled in the 1950s and 1960s, the ideas were primarily applied to over-the-horizon communications covering a wide range of frequency bands. The 3-30 MHz high-frequency (HF) band is used for ionospheric communications, and the 300 MHz-3 GHz ultra-high-frequency (UHF) and 3-30 GHz super-high-frequency (SHF) bands are used for tropospheric channels, the early models are still quite useful to help characterize fading effects in mobile digital communication systems. This tutorial addresses Rayleigh fading, primarily in the UHF band, that affects mobile systems such as cellular and personal communication systems (PCS). Part I of the tutorial itemizes the fundamental fading manifestations and types of degradation. Part II will focus on methods to mitigate the degradation. |
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