1 research outputs found
A priority leaky-bucket regulator for virtual path traffic in ATM networks
In integrated services networks (B-ISDN/ATM) incoming traffic streams
with different Quality of Service (QoS) requirements, sharing a single
contract for use of a policed virtual path, may be jointly regulated on
the basis of their type and QoS requirements to make the best use of
available bandwidth in the path. The shaping/policing mechanism may use
the information about the network policer located at the User-Network
Interface (UNI) to perform policing with a form of priority service to
ensure satisfactory levels of cell loss and delay for both realtime and
non-real time traffic. This paper proposes and analyzes such a priority,
buffered leaky-bucket mechanism for shaping/policing high-priority and
low-priority sources, which share an ATM virtual path under a single,
common user-network connection contract. The proposed priority traffic
regulator maintains a dedicated cell buffer for each type of traffic to
be able to trade off cell delay and loss (or tagging) on the basis of
the QoS requirements for each priority class. The analysis adopts a
Discrete Batch Markovian Arrival Process (D-BMAP) model for both
high-priority and low-priority sources. It is shown that the system
model has an M/G/1 type queuing structure, which is exploited for the
computation of the joint buffer content distribution and cell loss
probabilities of the high-priority and low-priority traffic streams. The
obtained numerical results capture the effect of the shaper/policer and
source parameters on the cell loss performance, and may be used for
design optimization. A comparison of the priority leaky-bucket with the
classical single buffer leaky-bucket regulator is carried out to
quantify the improvement in terms of bandwidth utilization. (C) 2001
Elsevier Science B.V. All rights reserved