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Managing ABR Capacity in Reservation-based Slotted Networks

Roya Ulrich and Pieter Kritzinger
fulrich@icsi.berkeley.edu, psk@cs.uct.ac.zag
The Networks Group International Computer Science Institute, and The Computer Science Depatrment University of Cape Town
TR-96-006 January 1996

Abstract For slotted networks carrying full multi-media traffic to work successfully, it is essential that connection setup and management is done well under all traffic conditions. Major challenges remain with the current state of the technology, however, particularly on how one copes with traffic bursts. Existing reservation-based networks do not allow the user to dynamically adjust his bandwidth requirements on demand. In this paper we propose a new scheme, called the reservoir scheme, which allows dynamic and distributed resource allocation. The basic idea behind the scheme is to reserve bandwidth with a guaranteed bit rate for each virtual circuit. The user is allowed to decentrally allocate additional bandwidth from an Available Bit Rate (ABR) reservoir to satisfy dynamic changes of Variable Bit Rate (VBR) traffic. The duration and bandwidth of this dynamic access are negotiated in the call setup phase and do not require any renegotiation with the service provider so that this solution overcomes the rigidity of current static bandwidth reservation schemes. The additional management requirements are low compared to other dynamic bandwidth reservation schemes. We also describe an analytic model and simulation which we used to determine whether it would be practical to apply the proposed scheme in a slotted network.

[Pieter Kritzinger is in the]

Computer Science Depatrment, University of Cape Town,
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