Rajiv S. Dighe

An UPC-based traffic control framework for ATM networks

Future broadband networks have to support new bandwidth intensive applications that will place stringent requirements on the network in terms of the QOS (quality of service) they receive. In spite of the the promise of abundant bandwidth, ATM would not be able to support such services unless adequate control is exercised within the network. In this paper, we propose a traffic control framework for ATM, that would provide guarantees on QOS for these new applications. Central to this framework is a traffic classification scheme that maps applications to specific traffic classes based on their QOS requirements and the statistical characteristics of their traffic, and a set of controls layered in time based on the time constant of events they control. The proposed traffic control framework can work across LANs, MANs, WANs, private and public networks in a seamless manner. The controls are designed to scale with distance, traffic volume and traffic type. A notable feature of this framework is that it depends on a minimum set of control functions to handle a wide range of traffic types. Further, it uses parameters for control that have already been standardized by ITU and the ATM Forum.

A link based alternative routing scheme for network restoration under failure

We present an alternative routing scheme which ensures that the network restores itself under any single link failure. In addition, our scheme has the advantage that restoration of the network occurs immediately on discovery of failure (without waiting for time consuming exchange of messages). An efficient heuristic algorithm, based on maximal-flow algorithm, is first used to partition the network into two parts (one carries the regular or primary traffic and the other is reserved to carry re-routed traffic in the event of failure). Then, we show how to use the results of the algorithm to actually find the alternative routes for a given call at the time of call setup.

Distributed source control: a network access control for integrated broadband packet networks

The authors propose a congestion control strategy called distributed source control (DSC), designed to address the integration of diverse traffic types in broadband packet networks. DSC is a rate-based network access control implemented at the asynchronous transfer mode (ATM) layer as a feedforward control, in conjunction with an adaptive end-to-end control between network edges. The authors examine the performance of high-speed data traffic such as large file transfers, still images, and document retrievals. The authors study DSCs integrability with real-time traffic such as voice and video. With the help of a simulation model of a broadband packet network (150 Mb/s), the authors quantify the improvement in network performance due to DSC. An analytic model for an access node under DSC is developed, and guidelines for sizing of buffers in the switch and for choosing the end-to-end window size are provided. >

A multidimensional framework for congestion control in B-ISDN

A multidimensional approach to congestion control in integrated broadband networks is described, and a framework for a congestion control strategy that is applicable to virtual-circuit-based services as well as connectionless services is developed. The proposed congestion control strategy is based on a set of temporal controls, classification of services is based on their traffic characteristics and quality of service (QOS) requirements, and partitioning of the control space is based on the reaction time of the controls and the network time constants. The congestion control framework is simple, scales as the delay-bandwidth product increases, and is well suited for the asynchronous transfer mode that is being promoted as the underlying transport for B-ISDN. >

IP switching over fast ATM cell transport (IPSOFACTO): switching multicast flows

This paper describes a method for mapping IP flows to ATM switches. No signaling is necessary to setup a path through ATM switches. Switch controllers run a IP routing protocol and execute IP forwarding. The IPSOFACTO component is responsible for mapping a IP flow to a switched path. The focus of this paper is primarily on switching IP multicast flows.

Framework for IP switching over fast ATM cell transport (IPSOFACTO)

This paper describes a method for mapping IP flows to ATM switches. No signaling is necessary to setup a path through ATM switches. Switch controllers run an IP routing protocol and execute IP forwarding. The IPSOFACTO component is responsible for mapping a IP flow to a switched path. Mechanisms for switching both multicast and unicast flows are described.

Performance analysis of multilevel congestion controls in BISDN

The paper presents a model of a network with multiple controls that are hierarchically arranged in time, based on the time constants of events they control. The authors model the network with such hierarchical controls as a closed multi-chain queueing network and use a quasi static approximation based on a hierarchical decomposition technique to solve the model. They determine the blocking probability at the call level and burst level, as well as the waiting time distribution for bursts that are blocked. They investigate the trade off in performance that can be achieved at different levels in the hierarchical control model.<<ETX>>