Analysis of bandwidth allocation strategies with accessrestrictions in broadband ISDN

Bandwidth allocation strategies with access restrictions for the integration of wideband (WB) and narrowband (NB) traffic in a broadband integrated services digital network (BISDN) are studied. Access restrictions are placed on both types of traffic to meet the grade of service required for each. The WB traffic is assumed nonqueuable, whereas the NB traffic may be queued. As an improved strategy, an access strategy which allows each type of traffic to use its bandwidth in the access-restricted region with the risk of being preempted by an arriving call for which the overflowed region is reserved is considered. Under this strategy, the preempted NB calls are queued at the head of a waiting room, and preempted WB calls are queued in another finite waiting room. The performance of these strategies is analyzed in terms of access delay for NB traffic and blocking probability for WB traffic by the matrix-geometric solution method. It is shown numerically that these strategies can easily be adapted to varying traffic loads by changing the restriction levels     

A multilevel optimal control approach to dynamic bandwidth allocation in broadband ISDN

In this paper a novel scheme for the dynamic allocation of bandwidth at the virtual path level in B-ISDNs is presented. A fluid flow model is developed to describe the time varying mean behaviour of a virtual path and serves as a state variable model. A multilevel optimal control theoretic approach is used in conjunction with the state model to derive a coordinated decentralised algorithm for virtual path bandwidth allocation. The integration of the virtual path bandwidth controller into a hierarchically organised network control scheme is incorporated in the problem formulation. The performance of the proposed scheme is evaluated using simulation.A version of this paper appears in the proceedings of INFOCOM'95.     

Evolution of ISDN towards broadband ISDN

Worldwide activities to evolve integrated services digital network (ISDN) into an optical-fiber-based universal broadband network have resulted in the first baseline documents, such as CCITT Recommendation I.121. The asynchronous transfer mode has been established as a key element of broadband ISDN (BISDN). The adoption of the G.707-709 recommendations on the new digital transmission hierarchy will also strongly influence further BISDN development. The author presents the current state of the BISDN discussion, especially within CCITT, briefly addressing broadband services and then concentrating on the user-network interface, as its definition is of utmost importance with respect to the introduction of a worldwide unique BISDN. Network scenarios and evolution and interworking aspects of the arising broadband realizations are also addressed     

Narrowband ISDN and broadband ISDN service and network interworking

For a significant period of time, B-ISDN will coexist with the 64-kb/s-based (narrowband) ISDN. The specification of a concept and the mapping functions employed for interworking between the two networks, in particular for voice services, is a major factor for the success of B-ISDN     

World-wide standardization of broadband ISDN

A growing market demand for high-performance voice, data, image and video networks, coupled with advances in high-speed technologies has heightened interest in broadband ISDN (BISDN) throughout the world. Network providers, equipment manufacturers and standards bodies are working jointly to accelerate the definition of BISDN interfaces in anticipation of emerging market opportunities. BISDN is being designed as the foundation upon which to implement very flexible, high-bandwidth, high-performance networks. A multiplexing concept called asynchronous transfer mode (ATM), which can offer bandwidth on demand at rates exceeding 150 Mb/s, high-speed packet switching, and an efficient protocol which adapts existing information streams into the ATM format are key attributes of the emerging BISDN network standards. This paper reviews the motivations behind BISDN, explains its key attributes and challenges and discusses possible strategies for evolving today's network toward BISDN.     

Narrowband and broadband ISDN CPE directions

Noting that ISDN customer premises equipment (CPE) is critical to the successful deployment of ISDN whatever the bandwidth, the author examines the market for narrowband and wideband integrated services digital network (NISDN and BISDN) CPE. He establishes the basic requirements for NISDN terminals and discusses terminal adaptors, digital telephone sets, screen-based telephony, workstations, customer premises networks, and CPE maintenance and upgrades. He examines the BISDN market and discusses the features and architecture of the terminals     

A framework for bandwidth management in ATM networks-aggregateequivalent bandwidth estimation approach

A unified framework for traffic control and bandwidth management in ATM networks is proposed. It bridges algorithms for real-time and data services. The central concept of this framework is adaptive connection admission. It employs an estimation of the aggregate equivalent bandwidth required by connections carried in each output port of the ATM switches. The estimation process takes into account both the traffic source declarations and the connection superposition process measurements in the switch output ports. This is done in an optimization framework based on a linear Kalman filter. To provide a required quality of service guarantee, bandwidth is reserved for possible estimation error. The algorithm is robust and copes very well with unpredicted changes in source parameters, thereby resulting in high bandwidth utilization while providing the required quality of service. The proposed approach can also take into account the influence of the source policing mechanism. The tradeoff between strict and relaxed source policing is discussed     

Distributed resource management and connection control for a multi-access interface to a broadband ISDN (BISDN)

A customer premises network (CPN) provides a common communications fabric to efficiently integrate the traffic of multiple terminals on a common access interface to a BISDN. An important consideration in choosing a CPN architecture is to facilitate terminal portability and application transparency, so as to accommodate standard broadband terminals and applications, requiring only minor modification to adapt them from the standard BISDN interface to the multi-terminal environment. This paper explores the multi-faceted issues of CPN transparency with an emphasis on the evolving BISDN control and management architecture. We introduce a control architecture that conforms to a rigorous separation between ‘call control’ and ‘connection management’. This allows the CPN to be transparent to the user to network signalling exchange, and to participate only in the connection management via a remote resource management protocol. More generally, this scheme allows a call control entity located in a local exchange node (LEN) to manage a distributed set of resources such as switches and multiplexors (and CPNs). This is achieved through the definition of a standard interoperable interface between the central call control entity and the connection control entities which may be remotely located in various network elements. The features and functionality for such an interface, which we term the bearer connection control interface, are described within the framework of the OSI remote management architecture. A standard remote resource management protocol allows for the co-operative sharing of resources across administrative domains. Although the importance of such a scheme is particularly visible as applied to remote CPN management, it is useful in other application domains where it is advantageous to distribute management processes.     

Management of capacity and control in broadband ISDN

The trend towards integration of services onto a single network and the addition of accompanying control features has led to an increase in the complexity of functional signalling protocols. A continuing dramatic reduction in the cost of traffic-carrying capacity has meant that call control costs are becoming an increasingly significant component of the total network cost. In BISDN, the support of many diverse services may result in an excessive control cost. To avoid this potential problem, virtual paths may be used. Capacity may be reserved on virtual paths to simplify the set-up procedure for individual calls. One benefit of this approach is that the cost of establishing a virtual path is shared among all individual connections which subsequently use it. However, this reduced control cost comes at the expense of installing additional traffic carrying capacity. This paper describes techniques for the management of traffic carrying capacity and control mechanisms in BISDN and presents a cost-benefit analysis to determine policies for reserving capacity on virtual paths. Significant savings in the total BISDN cost can result from the use of virtual paths.     

Standardization of a multi-configuration medium access protocol for broadband ISDN

This paper examines the current work within various standards bodies to define a multi-configuration medium access control (MAC) protocol for operation between broadband ISDN terminals. To begin, the configurations in which the MAC protocol is expected to operate are introduced. The relation between the MAC protocol and the broadband ISDN resource allocation schemes is then discussed. Several MAC protocol proposals currently being discussed in various standards bodies, each with unique assumptions regarding resource allocation in broadband ISDN, are then described and compared. Finally, areas for future work on this topic are identified.     

Broadband communication and its realization with broadband ISDN

In addition to narrowband services, future broadband networks will also include broadband services for applications like: high-speed communication of data, text and graphics person-to-person video communication, access to video information as well as broadcast of programs and data. Low terminal costs and service charges are essential with respect to a growing demand for new services, especially in the home. Broadband ISDN, to be developed on the basis of ISDN and using glass-fiber subscriber lines, will enable a wide range of applications satisfying the needs and requirements of the business and private sectors. The best technical solution from the aspect of user-friendliness and economy is to implement this broadband ISDN for all services with an evolutionary and flexible design. The broadband ISDN concept is not restricted to the public network and terminal equipment but also comprises private networks, information and program centers, etc. Many countries are pursuing the goal of this universal network for the future "information society". However, the approaches for setting up the broadband ISDN differ from country to country, depending on the particular technical and political situation. Standardization plays an important role with regard to "open broadband telecommunication", the worldwide trouble-free communication and information exchange of one party with any other.     

Multichannel bandwidth allocation in a broadband packet switch

The problem of bandwidth allocation in a packet switch supporting broadband services is addressed. To reduce the performance constraints imposed by limiting a data link to a single broadband packet channel, the author introduces the concept of channel group as a set of broadband packet channels that is viewed as a single data-link connection by routing entities. He uses a two-step bandwidth allocation scheme. At connection setup time, a call is allocated to a channel group. At transmission time, specific channels of a group are optimally allocated to the packets destined to the group. Because of the statistical smoothing of the large number of sources served by a channel group, the traffic performance of the switch is improved. This scheme also allows super-rate switching, i.e., the support of services with peak bandwidth exceeding the capacity of a single packet channel. The author shows the feasibility of this scheme in a Batcher-banyan switch, by implementing in hardware the bandwidth allocation at transmission time. Performance improvements obtained by this scheme are also provided in different traffic environments     

Evolution of metropolitan area networks to broadband ISDN

Broadband architecture and network evolution strategies based on interface standards emerging from the IEEE 802.6 MAN Committee and the American National Standards Institute (ANSI) T1S1 and CCITT Working Groups on broadband integrated services digital networks (BISDN) are outlined. The recent history of both the MAN and BISDN standards activities is traced, and some of the motivations behind specific developments are discussed. In the context, local area networks (LANs) and MANs are compared and contrasted, with special attention given to requirements specific to a public MAN. The convergence of the MAN and BISDN protocols is examined. The benefits of commonality between these two standards are described in terms of lower-cost network architectures, and terminal equipment is examined. It is shown that broadband networks can exploit the synergy between 802.6-based MANs and wider-area BISDN networks, and that 802.6-based MANs can gracefully evolve into countrywide networks using BISDN asynchronous transfer mode (ATM) switching. Example networks are used to illustrate the evolution proposals     

Bandwidth quantization and states reduction in the broadband ISDN

If a network supports only certain rates, we say its bandwidth is quantized. In a quantized-bandwidth network, a customer may be forced to use the next higher rate if the requested rate is not supported. The result is a higher blocking probability and a lower throughput. The throughput loss due to quantization is called the quantization loss, and its related issues are the focus of this paper. We show that the quantization loss is insensitive to capacity scaling and traffic-loading. More important, it is hardly as large as is thought. Even for a network, such as ATM, intending to support a continuous bit rate, bandwidth quantization can be a powerful tool for states reduction. States reduction is shown to be indispensable for solving many problems, such as routing and capacity planning, of a broadband network     

A pipelined, multiprocessor architecture for a connectionlessserver for broadband ISDN

The direct provision of connectionless service in BISDN calls for servers that are connected to or are part of an ATM network to provide the routing function at input speeds up to 622 Mb/s. Routing is achieved in such a server by changing the VCI/VPI headers in the ATM cells; actual switching is done by existing switches in the ATM network. The paper presents an architecture capable of executing all the functions of a server at input speeds up to 622 Mb/s, scalable to multiple inputs at that speed, making use of processors and special hardware that are available today. To avoid storing large quantities of data, the architecture routes data packets by examining routing information in the initial cell of the packet and routing subsequent cells as they arrive rather than waiting until the complete packet has arrived. It is capable of handling packets that have been multiplexed at the SAR sublayer using AAL Type 3/4 and, with minor modifications, could also handle Type 5 traffic. Arguments are also presented for the use of AAL Type 5 for the direct connectionless service     

Two years of experience with broadband ISDN field trial

The BERKOM project, which represents the largest broadband ISDN (BISDN) field trial in the world, is discussed. The objectives of the field trial are outlined. Three aspects of the test network are then addressed: system concept, system extension, and system experience. Tests demonstrated that the overall system performance met all requirements for telecommunication applications     

An expandable time-division circuit switching LSI and networkarchitecture for broadband ISDN

A broadband network architecture is proposed that integrates multimedia services, such as data, video, and telephony information, using 52-Mb/s based STM-paths at the user network interface (UNI). The user can access any new service via the STM-based access network via either synchronous transfer mode (STM) switching or asynchronous transfer mode (ATM) switching. STM circuit switching supports long duration, constant bandwidth data transfer services such as video and high-definition television (HDTV) distribution and will also be used for the crossconnect system. Circuit switching can provide transparent transmission during long connection periods. This paper also proposes an expandable time-division switch architecture, an expandable time-division switching LSI, and an expandable switching module for small to large size system applications. The proposed time-division switching LSI, module, and system handle 52-Mb/s bearer signals and have throughputs of 2.4 Gb/s, 10 Gb/s, and 40 Gb/s, respectively. The time-division switch realizes video distribution with 1:n connections. Finally, a local switching node that features an expandable 52-Mb/s time-division circuit switching network is shown for multimedia access networking     

Traffic studies of a multiplexer in an ATM network and applications to the future broadband ISDN

In the first part of this paper the influence of the arrival process on these three performance parameters is discussed. The values of these three performance parameters depend strongly on the utilization distribution over the input trunks of the multiplexer while the total utilization on the input trunks is fixed. If there is the same utilization on all input trunks, the values of these three performance paramters reach a maximum. This result is also valid for an ATM switching matrix with a separate FIFO buffer at each output trunk. In the second part of this paper some examples are provided of how to apply the results of these studies to the future broadband ISDN which is intended to transmit services with very high bit rates (e.g. 135 Mb/s) as well as services with very low bit rates (e.g. 64 kb/s).