Study Group report
This is the final report on the problem of data packet loss in a queue with limited buffer, brought to ESGI49 by Motorola.

Report author
David Allwright (Smith Institute)

Introduction
A system that occurs in several contexts in computer and data networks has the generic form wth N sources sharing a single channel, and their access to this channel is administered by a resource management system which has a limited buffer space. The sources transmit packets in bursts, and in some circumstances (e.g. if the buffer is full) some of the packets may be lost. The source receives an explicit feedback signal from the system reporting the packet loss ratio for the burst. The size of the next burst is determined by the source as a function of this packet loss ratio. The time between sending a burst of packets and receiving the feedback packet loss signal is called the round trip time. It is variable due to queuing within the resource management system and channel variability. The elements of the resource management system are a service discipline that schedules the packets, a buffer system that stores the packets waiting for service, and a packet discard policy that discards incoming packets depending on the buffer occupancy. The problem is to find the steady state distribution of the packet loss ratios, and other information about the statistics of the distribution, e.g. the variance of the packet loss distribution.

Download 'LimitedBuffers.pdf' (135 Kb).