Showing papers on "Broadband networks published in 1996"

Broadband integrated networks

Abstract: Growth in broadband integrated network technologies like ATM, ISDN, and frame relay has been phenomenal in recent years. This book focuses on the quantitative methods, such as modeling and performance analysis in the high-speed ATM networking environment, as opposed to qualitative overviews. Covers the types of services provided over ATM networks, the ATM protocol model, Broadband ISDN and ATM, traffic characterization, access control in broadband networks, ATM switches, effective capacity, and feedback congestion control. For communication specialists, especially those working in the telecommunications industry.

Video pedestal network

Abstract: An architecture (200) for distributing digital information to subscriber units (202) wherein selection from among multiple digital services is accomplished by transmitting a tuning command from a subscriber unit to an intermediate interface (206). The intermediate interface (206) selects the desired service from a broadband network and transmits it to the subscriber unit (202) over a bandwidth-constrained access line. The bandwidth-constrained access line may be implemented with existing infrastructure, yet the subscriber unit (202) may access a wide variety of digital information available on the broadband network. Universal broadband access is thus provided at low cost. Output bandwidth of broadcast equipment may also be optimized.

A wideband all-optical WDM network

Abstract: We describe some of the results of the Advanced Research Projects Agency (ARPA) sponsored Consortium on Wideband All-Optical Networks in developing architectures, technology components, and applications for the realization of scaleable, wideband, and transparent optical wavelength-division multiplexing (WDM) networks. Our architecture addresses all-optical transport over the wide, metropolitan, and local areas. It utilizes wavelength partitioning, routing, and active multiwavelength cross-connect switches to achieve a network that is scaleable in the number of users, data rates, and geographic span. The network supports two services which can be point-to-multipoint or multipoint-to-multipoint simplex or duplex connections. The A service is a transparent physically circuit-switched service and the B-service is a scheduled time-slotted circuit which is transparent within its time slots. We have developed a 20-channel local and metropolitan area WDM testbed deployed in the Boston area, now undergoing characterization and experimental applications.

Stochastic networks : theory and applications

Abstract: 1. Convergence to equilibria for fluid models of FIFO and processor sharing queueing networks 2. Optimal draining of fluid re-entrant lines: some solved examples 3. On the approximation of queueing networks in heavy traffic 4. The BIGSTEP approach to flow management in stochastic processing networks 5. Queue lengths and departures at single-server resources 6. Large deviations of stationary reflected Brownian motions 7. Limit theorems for workload input models 8. Notes on effective bandwidths 9. Traffic characterisation and effective bandwidths for broadband network traces 10. Nonparametric estimation for quantities of interest in queues 11. The asymptotic behaviour of large loss networks 12. Admission controls for loss networks with diverse routing 13. On load balancing in Erlang networks 14. Analysing system behaviour on different timescales 15. Optimal returns and suboptimality bounds for systems satisfying generalised conservation laws 16. Approximate solutions for open networks with breakdowns and repairs 17. Stationary ergodic Jackson networks: results and counter-examples 18. The Cesaro limit of departures from certain ./GI/1 queueing tandems 19. The Poisson-independence hypothesis for infintely-growing fully-connected packet-switching networks 20. A bibliographical guide to self-similar traffic and performance modeling for modern high-speed networks

Full service network

Abstract: A digital switching network is described which accommodates a full range of broadband and narrowband digital technologies, including video, wideband data, narrowband data, video on demand and telephone channels in an integrated manner. Optical fiber connects information sources to the switching component of the network utilizing a standardized transport stream such as SONET OC-N. A broadband ATM switch, a digital cross-connect switch or other distribution mechanisms may be utilized to interconnect information sources and subscribers. A level 1 gateway is utilized to control access to all information resources on the network.

Source models for VBR broadcast-video traffic

Abstract: Traffic from video services is expected to be a substantial portion of the traffic carried by emerging broadband integrated networks. For variable bit rate (VBR) coded video, statistical source models are needed to design networks that achieve acceptable picture quality at minimum cost and to design traffic shaping and control mechanisms. For video teleconference traffic Heyman et al. (1992) showed that traffic is sufficiently accurately characterized by a multistate Markov chain model that can be derived from three traffic parameters (mean, correlation, and variance). The present authors describe modeling results for sequences with frequent scene changes (the previously studied video teleconferences have very little scene variation) such as entertainment television, news, and sports broadcasts. The authors analyze 11 long sequences of broadcast video traffic data. Unlike video teleconferences, the different sequences studied have different details regarding distributions of cells per frame. The authors present source models applicable to the different sequences and evaluate their accuracy as predictors of cell losses in asynchronous transfer mode (ATM) networks. The modeling approach is the same for all of the sequences but use of a single model based on a few physically meaningful parameters and applicable to all sequences does not seem to be possible.

Performance model of interactive video-on-demand systems

Abstract: An interactive video-on-demand (VoD) system allows users to access video services, such as movies, electronic encyclopedia, interactive games, and educational videos from video servers on a broadband network. This paper develops a performance evaluation tool for the system design. In particular, a user activity model is developed to describe the usage of system resources, i.e., network bandwidth and video server usage, by a user as it interacts with the service. In addition, we allow batching of user requests, and the effect of such batching is captured in a batching model. Our proposed queueing model integrates both the user activity and the batching model. This model can be used to determine the requirements of network bandwidth and video server and, hence, the trade-off in communication and storage costs for different system resource configurations.

Resource management system for a broadband multipoint bridge

Abstract: The use of a bridge (also known as a multipoint central unit) to enable multipoint communications over point to point narrowband-ISDN connections is well established. We deal with multipoint bridging for a broadband network environment. We explain the benefits of employing a bridge in that context and highlight the new design problems and challenges. Of particular importance is the need for a bridge resource management system which can be used in conjunction with end to end contracts for quality of service. We describe a model for managing bridge resources based on the estimated requirements of audio and video processing functions. Aspects of the initial system design are presented.

ATM network design and optimization: a multirate loss network framework

Abstract: Asynchronous transfer mode (ATM) network design and optimization at the call-level may be formulated in the framework of multirate, circuit-switched, loss networks with effective bandwidth encapsulating cell-level behavior. Each service supported on the (wide area, broadband) ATM network is characterized by a rate or bandwidth requirement. Future networks will be characterized by links with very large capacities in circuits and by many rates. Various asymptotic results are given to reduce the attendant complexity of numerical calculations. A central element is a uniform asymptotic approximation (UAA) for link analyses. Moreover, a unified hybrid approach is given which allows asymptotic and nonasymptotic methods of calculations to be used cooperatively. Network loss probabilities are obtained by solving fixed-point equations. A canonical problem of route and logical network design is considered. An optimization procedure is proposed, which is guided by gradients obtained by solving a system of equations for implied costs. A novel application of the EM algorithm gives an efficient technique for calculating implied costs with changing traffic conditions. Finally, we report numerical results obtained by the software package TALISMAN, which incorporates the theoretical results. The network considered has eight nodes, 20 links, six services, and as many as 160 routes.

A wavelength rerouting algorithm in wide-area all-optical networks

Abstract: This paper considers rerouting and minimization of incurred disruption due to rerouting in a wide-area all-optical wavelength division multiplexed (WDM) network with random circuit arrivals and departures. One limitation of such a network is the wavelength continuity constraint imposed by the all-optical cross-connect switches which do not allow a circuit to be placed on a nonwavelength-continuous route. Wavelength rerouting is proposed to rearrange certain existing circuits to create a wavelength-continuous route in order to accommodate a new circuit. To reduce the disruption period, move-to-vacant wavelength-retuning (MTV WR) is used as the basic operation of circuit migration, in which a circuit is moved to a vacant wavelength on the same path, and parallel MTV WR rerouting is used to reroute multiple circuits. An optimal algorithm is developed to minimize the weighted number of rerouted circuits with parallel MTV WR rerouting. In our test network, wavelength rerouting can effectively alleviate the wavelength continuity constraint by reducing call blocking probability an average of 30 % while reducing the number of rerouted circuits and the disruption period,.

Realizing a foundation for programmability of ATM networks with the binding architecture

Abstract: A conceptual framework, called the binding model, for the creation, deployment and management of multimedia services on ATM-based broadband networks with end-to-end quality-of-service (QoS) guarantees is presented. The key function of the associated binding architecture is to provide an open programmable environment that facilitates the easy creation of flexible services. We describe the implementation of a prototype binding architecture called xbind as a middleware toolkit for building open programmable ATM networks. Finally, we present our initial experiences with experimenting and deploying xbind over an ATM testbed and highlight some of the lessons learned.

Asynchronous transfer of video

Abstract: Video transfers across IP and ATM networks have received much research attention during the last ten years. Various video services are expected in the future, enabled by the rapid development in video coding and broadband network technology. This article gives an introduction to the issues involved in asynchronous video transfers. Brief overviews of video coding, rate control, and multiplexing, as well as delay, error, and loss control are also given.

A signaling and control architecture for mobility support in wireless ATM networks

Abstract: This paper presents a signaling and control architecture for mobility support in a "wireless ATM" network that provides integrated broadband services to mobile terminals. ATM signaling and wireless control capabilities required for mobility services are discussed, and preliminary solutions are given for selected major functions. Potential extensions to ITU standard Q.2931 ATM signaling are proposed to support mobility related functions such as handoff and service parameter/QOS renegotiation. A custom wireless control protocol for supporting terminal migration, resource allocation, handoff, etc. is outlined for a wireless ATM network. Preliminary experimental results validating the proposed handoff control protocol on an ATM network testbed are briefly outlined.

Adaptive digital access protocol: a MAC protocol for multiservice broadband access networks

Abstract: The authors describe a protocol that can adapt to the changing demands of a mix of synchronous transfer mode (STM) and asynchronous transfer mode (ATM) applications and efficiently allocate bandwidth to a variety of bursty traffic sources. In the case of a hybrid fiber-coaxial (HFC) network, the protocol resides in customer premises equipment (CPE) and a common head-end/central-office (HE/CO) controller. A medium-access control (MAC) processor provides for dividing the time domain for a given digital bitstream into successive frames, each with multiple STM and ATM time slots. Within the STM region of a frame, variable-length time slots are allocated to calls (e.g., telephony, video telephony) requiring different amounts of bandwidth. In the upstream channels, a contention access signaling time slot is also provided in the STM region for call control and setup requests. Within the ATM region, fixed-length time slots accommodate one individual ATM cell. These ATM time slots may be reserved for a user for either the duration of a call or a burst of successive ATM cells, or shared via a contention process. At least one contention time slot is available for signaling messages related to ATM call control and setup requests. The MAC-layer protocol, its relation to circuit- and ATM-amenable applications, and its performance with respect to throughput, latency, and bandwidth efficiency for several service scenarios are examined.

Block spectrum receiver for a broadband communications system

Abstract: A communication system for coupling telephony or other signals to a broadband network such as a CATV network The system transmits a multiplex of telephony signals in the forward band of the broadband network, with individual signals directed to an addressed subscriber Telephony signals returning from subscribers upstream to a headend unit (HIU) are modulated onto the reverse band of the broadband network in a frequency division multiple access (FDMA) arrangement The upstream modulated telephony signals are received at a telephony network interface at the HIU coupled to the broadband network A group of reverse band modulated telephony signals are received at a group receiver or channelizer The group receiver processes all upstream telephony signals within a selected spectral subband in the reverse band to apply a receiver matched filter with a weighted overlap and add circuit, and are then converted to baseband by an FFT circuit The group receiver provides a serial data stream representing the baseband telephony signals The baseband telephony signals are processed to derive demodulated telephony signals The demodulated telephony signals are coupled to the telephony network

Architecture of a broadband mediaprocessor

Abstract: A broadband mediaprocessor is a general-purpose computer system which reaches the goal of communicating and processing at broadband rates using compiled software rather than special-purpose hardware. MicroUnity's architectural family of broadband mediaprocessors reduce costs of broadband communications systems and enable deployment of new communications services by transmitting software through digital networks.

PRMA/DA: a new media access control protocol for wireless ATM

Abstract: We propose a media access control (MAC) protocol for wireless local area networks (LANs) that is capable of supporting various types of traffic demands, such as constant bit rate (CBR) voice, variable bit-rate (VBR) video, and packet data. In addition, the proposed protocol provides a seamless connectivity to a broadband ATM backbone network. Our protocol, having an air interface comparable to ATM, adopts a dynamic channel allocation scheme which enables expeditious network-access and utilizes bandwidth resource efficiently. The simulation results presented show the improvements of dynamic channel allocation over the static channel allocation scheme in terms of key performance metrics such as: throughput, call blocking probability, network access delay and cell transmission delay.

On the relevance of time scales in performance oriented traffic characterizations

Abstract: Efficient methods for congestion control in high-speed communication networks will be based on reasonable characterizations for traffic flows and time scale decompositions of the network dynamics. A key problem for modern network designers is to characterize/model the "bursty" traffic arising in broadband networks with a view to predicting and guaranteeing the performance. We attempt to unify several approaches ranging from histogram/interval based methods to "frequency domain" approaches by further investigating the asymptotic behavior of a multiplexer carrying a large number of streams. This analysis reveals the salient traffic/performance relationships which should guide us in selecting successful methods for traffic management and network dimensioning.

Supporting real time VBR video using dynamic reservation based on linear prediction

Abstract: Variable bit rate (VBR) video traffic is expected to be one of the major applications that need to be supported by broadband packet-switched networks A dynamic bandwidth allocation strategy used to support VBR video traffic is proposed This strategy predicts the bandwidth requirements for future frames using either adaptive or non-adaptive least mean square (LMS) error linear predictors The adaptive technique does not require any prior knowledge of the statistics, nor assumes stationarity Several reservation schemes are also presented Analysis using six one-half hour video traces indicate that prediction errors for the bandwidth required for the next frame are almost white noise By reserving a bandwidth equal to the predicted value, only the prediction errors need to be buffered Because the errors are almost white noise, a small buffer size, high utilization, and a small delay are achieved Simulation results for 1-step linear predictor show that for the same expected cell loss, the buffer size is reduced by more than a factor of 100 and the network utilization is increased by more than 250% as compared to a fixed service rate

Fair-efficient call admission control policies for broadband networks—a game theoretic framework

Abstract: A fundamental problem in connection oriented multiservice networks (ATM and STM) is finding the optimal policy for call acceptance. One seeks an admission control policy that efficiently utilizes network resources while at the same time being fair to the various call classes being supported. The theory of cooperative games provides a natural and precise framework for formulating such multicriterion problems as well as solution concepts. The authors describe how this framework can be used for analysis and synthesis of call admission strategies in broadband networks. In particular they investigate the Nash (1950), Raiffa-Kalai-Smorodinsky (Raiffa, 1953; Kalai and Smorodinsky, 1975), and modified Thomson (Cao, 1982) arbitration solutions from game theory. The performance of all solutions is evaluated by applying the value iteration algorithm from Markov decision theory. The approach is illustrated on a one-link network example for which the exact solutions can be achieved. The results indicate that the arbitration schemes from game theory provide some attractive features especially when compared to traditional control objectives: blocking equalization and traffic maximization. The authors also compare the optimal solutions with some simplified policies belonging to four different classes: complete sharing, coordinate convex, trunk reservation, and dynamic trunk reservation. The comparison indicates that in many cases, the trunk reservation and dynamic trunk reservation policies can provide fair, efficient solutions, close to the optimal ones.

Techno-economic evaluation of narrowband and broadband access network alternatives and evolution scenario assessment

Abstract: The paper presents the main results obtained within the Research in Advanced Communications in Europe (RACE) project: 2087 TITAN regarding minimum-risk introductory routes for new narrowband and broadband services in the residential and small business market. The project developed a methodology and a tool for techno-economic evaluation of advanced narrowband and broadband telecommunications networks and services. Results from four extensive access network studies are presented. For the narrowband services, optical access and radio in the local loop have been assessed and compared to conventional copper layout in a greenfield environment. Access network upgrade strategies for emerging new broadband services have been evaluated in three studies, with technological options ranging from enhanced copper to hybrid-fiber-coax (HFC) and broadband passive optical networks. An extensive study on different broadband access network upgrade alternatives for public network operators (PNOs) were carried out, taking into account the diversity of conditions met today by European countries. In another study, the effect of competition In the access network was modeled assuming two main operators sharing the market. Broadband upgrade alternatives were evaluated for a new cable operator, competing with the dominant public network operator. In addition, video-on-demand (VoD) and Internet access upgrades have been analyzed. The paper demonstrates the viability of techno-economic studies for the access network, including in-depth analysis of the time-dependence of component cost, tariffs, service penetrations and market shares.

Method and system for applying fiber to the curb architecture using a broadband gateway at service locations, including homes

Abstract: A system for connecting fiber optic telecommunications and video services to individual homes using a single twisted pair or coaxial cable line between the optical network unit and each service location. The single twisted pair or coaxial cable line connects to a broadband gateway located at the home, from which both telephone lines and other services may be delivered. Under this invention, the optical network units serve solely as connection and routing points for the drop lines, with telephone, video, and other services derived through the broadband gateway.

System and method for providing videoconferencing services

Abstract: A broadband system includes a broadband switch network, a broadband session controller, and a broadband service control point. The broadband network provides connections between information sender/receivers in response to instructions from a broadband service control point or in response to requests originated by an information sender/receiver. The broadband service control point provides processing instructions and/or data to the broadband controller and information sender/receiver. Applications supported by the broadband network include video-on-demand and videoconferencing services for system users. For video-on-demand, a settop controller is associated with a video display of each system user. One or more video information providers ("VIPs") stores video information to be sent to the user's settop controller via the broadband switch network. The broadband session controller communicates with the user's settop controller and VIPs and requests processing information from the broadband service control point in response to predetermined triggers. The broadband session controller instructs the broadband switch network to establish the broadband connection between the VIP and a predetermined settop controller. For settop controller-based videoconferencing, the settop controller controls cameras, microphones, video displays, and speakers. In addition, an integrated service control point integrates broadband and telephone networks to provide efficient and effective integrated broadband and telephone services. Both broadband and telephone services can be provisioned via a video interface at a user's remote location. Also, the integrated network provides unique caller identification delivery services.

MLAP: a MAC level access protocol for the HFC 802.14 network

Abstract: Interactive residential broadband/multimedia services are expected to be the next main event in the cyberspace experience. The large excess bandwidth (well over 300 MHz) available in today's cable TV (CATV) hybrid fiber/coaxial (HFC) plants is an ideal candidate to provide the underlying communications infrastructure for interactive digital services to the home; cable operators that have not yet upgraded their all-coaxial plants to HFC are quickly moving in this direction. MLAP is a flexible ATM-friendly MAC protocol that is capable of supporting various types of traffic with diverse quality-of-service requirements. We introduce a very versatile MAC protocol for the HFC 802.14 network. MLAP can provide integrated broadband services to the home, internetwork easily with ATM wide area networks, support QoS constraints for various types of traffic, and operate over a variety of physical layer protocols. Our presentation is only an extended summary of our medium-sharing protocol proposal to the IEEE 802.14 WG. We consider only error-free system operation. MLAP provides for the use of timers for the recovery of error situations in the network. MLAP is also supported by a management suite of protocols for management of the overall system.

Method and apparatus for integrating telephone and broadband networks

Abstract: An integrated broadband/telephone service control point connected to both a broadband network and a telephone network, comprising a first database having a plurality of broadband processing records, a second database having a plurality of call processing records, a system responsive to a first set of triggers from the broadband network for executing one or more of the broadband procession records and returning processing instructions to the broadband network, and a system responsive to a second set of triggers from the telephone network for executing one or more of the call processing records and returning processing instructions to the telephone network.

Implementation of STARNET: a WDM computer communications network

Abstract: STARNET is a broadband backbone optical wavelength-division multiplexing (WDM) local area network (LAN). Based on a physical passive star topology, STARNET offers all users two logical subnetworks: a high-speed reconfigurable packet-switched data subnetwork and a moderate-speed fix-tuned packet-switched control subnetwork. Thus, STARNET supports traffic with a wide range of speed and continuity characteristics. We report the analysis and implementation of an entire STARNET two-node network, from the optical to the computer layer, at the Optical Communications Research Laboratory (OCRL) of Stanford University. To implement the two logical subnetworks, we designed and implemented two different techniques: combined modulation and multichannel subcarrier multiplexing (MSCM). OCRL has already demonstrated several combined modulation techniques such as phase shift-keyed and amplitude shift-keyed (PSK/ASK), and differential phase shift-keyed and amplitude shift-keyed (DPSK/ASK), yielding combined ASK/DPSK modulation receiver sensitivities better than -32 dBm. OCRL has designed and implemented a high-speed high-performance packet-switched STARNET computer interface which enables high-throughput transfer to/from host computer, low latency switching, traffic prioritization, and capability of multicasting and broadcasting. With this interface board, OCRL has achieved average transmit and receive throughputs of 685 Mb/s and 571 Mb/s, respectively, out of the 800 Mb/s theoretical maximum of the host computer bus. The incurred packet latency due to the interface for a specified multihop network configuration has been simulated to be 24 /spl mu/s. Using simulation and experimental results, it is shown that STARNET is highly suitable for high-speed multimedia network applications.

Performance of simulcast wireless techniques for personal communication systems

Abstract: Broadband analog transport facilities using fiber or fiber/coax cable can play a significant role in the evolution of the network infrastructure for personal communications services (PCSs). Low-power PCS systems require a dense grid of radio ports to provide connectivity to the telephone network. Analog transport has a number of important advantages over digital transmission facilities, including the flexibility to support a variety of air interface formats, shared infrastructure cost with other services such as video distribution, and centralized call processing allowing the use of low cost and simple radio ports. A simulcast technique can be used in such systems to permit low rates of handoff (no handoff within each simulcast area) and sharing of hardware resources among multiple radio ports. This paper provides a detailed model and a simulation analysis of the cochannel interference and noise performance as well as the resource sharing benefit of a simulcast PCS system. Several potential PCS air interfaces are considered, including time division multiple access (TDMA) and code division multiple access (CDMA) techniques. Our investigation shows that the impact of multiple antenna noise in a simulcast system is offset by the improved signal-to-interference (SIR) ratio brought about by distributed antennas. Even with distributed antennas, multiple antenna noise places a limit on the maximum number of radio ports that can be assigned to each simulcast group. This limit, however, is shown to have little impact on the achievable resource sharing benefit of simulcasting (i.e., grouping beyond this limit has diminishing returns). A saving of 40% to 60%, in terms of the required central hardware resources, is typical for both TDMA and CDMA systems in suburban environments.