ISSN:0737-2884    

DOI:10.1002/sat.4600090502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe greatly increased capacity and capabilities of terrestrial fibre networks, current and future satellites bring forth key issues relative to ISDN and other advanced communications concepts. This paper explores a brief history of the development and characteristics of both satellite and fibre, together with a description of advanced satellite concepts. Key advantages and disadvantages of satellites are described and related to future communications environments. These analyses are then discussed relative to their impact and implications on the design and operation of ISDN networks.

ISSN:0737-2884    

DOI:10.1002/sat.4600090503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThe increasing demand for communication services, coupled with recent technological advances in communication media and switching techniques, has resulted in a proliferation of new and expanded services. Currently, networks are needed which can transmit voice, data and video services in an application‐independent fashion. Unified approaches employ a single switching technique across the entire network bandwidth, thus allowing services to be switched in an application‐independent manner. This paper presents a taxonomy of integrated‐service networks, including a look at NISDN, while focusing on unified approaches to integrated‐service networks.The two most promising unified approaches are burst and fast packet switching. Burst switching is a circuit switching‐based approach which allocates channel bandwidth to a connection only during the transmission of ‘bursts’ of information. Fast packet switching is a packet switching‐based approach which can be characterized by very high transmission rates on network links and simple, hard‐wired protocols which match the rapid channel speed of the network. Both approaches are being proposed as possible implementations for integrated‐service networks. We survey these two approaches, and also examine the key performance issues found in fast packet switching. We then present the results of a simulation study of a fast packe

ISSN:0737-2884    

DOI:10.1002/sat.4600090504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper presents proposals and justification for standards governing the implementation of integrated service digital networks (ISDN). Using several programming protocols in a layered architecture provides continuing service during system evolution. The authors use a corporate communications environment for examples as the most probable initial implementation of the networks described. Some ISDN sites are operating, although not yet on a global scale, and present the building blocks for more advanced services in the near future. The authors present arguments supporting a concerted effort be started now to establish global standards for ISDN, so that design and development can comply in the most time‐effective manne

ISSN:0737-2884    

DOI:10.1002/sat.4600090505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractThis paper describes the integrated services digital network (ISDN) basic rate interface (BRI) two‐wire U interface and the transceiver necessary for the digital transmission of 160 kb/s of information over unshielded twisted pair transmission media. Topics discussed include the U interface structure and framing as described in the American National Standards Institute (ANSI) T1.601 specification, and the VLSI implementation of the ISDN U transceiver. Pertinent transceiver design issues addressed include the type of line code used, such as 2B1Q or 4B3T, echo cancellation, near end crosstalk, equalization and sampling rate

ISSN:0737-2884    

DOI:10.1002/sat.4600090506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractOne of the most promising approaches for high speed networks for integrated service applications is fast packet switching, or ATM (asynchronous transfer mode). ATM can be characterized by very high speed transmission links and simple, hard‐wired protocols within a network. To match the transmission speed of the network links, and to minimize the overhead due to the processing of network protocols, the switching of cells is done in hardware switching fabrics in ATM networks.A number of designs have been proposed for implementing ATM switches. Although many differences exist among the proposals, the vast majority of them are based on self‐routeing multistage interconnection networks. This is because of the desirable features of multi‐stage interconnection networks such as self‐routeing capability and suitability for VLSI implementation.Existing ATM switch architectures can be classified into two major classes: blocking switches, where blockings of cells may occur within a switch when more than one cell contends for the same internal link, and non‐blocking switches, where no internal blocking occurs. A large number of techniques have also been proposed to improve the performance of blocking and non‐blocking switches. In this paper, we present an extensive survey of the existing proposals for ATM switch architectures, focusing on their perform

ISSN:0737-2884    

DOI:10.1002/sat.4600090507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractTwo major ISDN applications which will undoubtedly affect world‐wide telecommunications in the coming decade are discussed. They are: (1) video transmission and (2) image transmission.Brief reviews of videophone chronicle and the current video coding technologies are presented. The application of videophones usingp× 64 (CCITT coding algorithm up to 1·5 Mb/s) and the DCT (discrete cosine transform) algorithm for narrowband ISDN are discussed. Broadcast TV quality DS3‐45 MB/s video codecs are also briefly discussed as a probable videophone system in the broadband ISDN era.The explosive growth of facsimile services is reviewed, and the progress of image coding technologies and their standards are covered. The prospects of high resolution image transfer systems with ISDN are addr

ISSN:0737-2884    

DOI:10.1002/sat.4600090508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractWe explore the use of the two current architectures for broadband integrated services digital networks (BISDN) as being defined in IEEE P802.6 (local and metropolitan area network)1and ANSI‐accredited Committee T1's T1S1.5 baseline document.2The standard currently defines procedures for the median access control (MAC) layer and interfaces for some upper layer services. We, therefore, use the two services defined by the adaptation layer, namely messaging and streaming, to compare their relative performance. It is shown that many conditions are necessary for streaming to out‐perform messaging. We then simulate the performance behaviour of these signalling protocols required for the isochronous services of IEEE P802.6 to determine end‐to‐end delay. This allows us to extend such predictions to the use of IEEE P802.6 as a backbone for concatenat

ISSN:0737-2884    

DOI:10.1002/sat.4600090509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA cubic (three‐dimensional) framework is proposed for mapping various information communications services. The framework implies the important aspect of information technology (IT), or C&C (integration of computers and communications) technology as follows. The first axis is based upon the service classification made for BISDN‐relevant services by the CCITT. This ‘communications’ axis covers not only the simple communication, or ‘space‐wise information transfer’, but also messaging, retrieval etc. as ‘the combined space/time‐wise information transfer’. The second axis represents ‘the multiplicity of media use’ in the human interface of information handling systems. The third axis represents the extent of ‘information processing/conversion’ or the level of computer technology penetration. In the latter part of this paper, the important interrelations between computer communications services and ISDN deployment are discussed using the scope of the above‐proposed cubic map. The penetration of PMI (personal machine intelligence) to the same level as telephone set and television set, and the corresponding computer communications services requirements are identified as a fundamental drivin

ISSN:0737-2884    

DOI:10.1002/sat.4600090510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY

摘要:

AbstractA technique for the classification and evaluation of hierarchical access integration policies of ISDN channels is proposed. The essence of the basic control decisions based on several parameters of the servers and channel is captured in a single priority‐based‐layered model of multiple queues. We solve for the resulting delay of different policies and investigate the performance in one tractable limit of this model. Using our understanding of the problem parameters and their interaction, we propose a number of heuristic policies for the general model. The results of the general problem complexity investigations suggest the use of simulation models. Problem parameters considered are channel acceptable access delay value, number of servers needed, and flow duration time of a request. Preemptive and non‐pre‐emptive policies on queued traffic are considered. Performance considers average delay, delay variation and channel utilization. Simulation data on these policies suggest that policies that favour shorter services given better overall delay over a wide range of system parameters. Policies that favour longer and broadband services, on the other hand, show better quality and smaller delay va

ISSN:0737-2884    

DOI:10.1002/sat.4600090511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1991

数据来源: WILEY