The major challenge in the design of an integrated network is the integration and
support of a wide variety of applications. To provide the requested performance
guarantees, a traffic control strategy has to allocate network resources according
to the characteristics of input traffic. Specifically, the definition of traffic characterisation
is significant in network conception. In this thesis, a traffic stream
is characterised based on a virtual queue principle. This approach provides the
necessary link between network resources allocation and traffic control.
It is difficult to guarantee performance without prior knowledge of the worst
behaviour in statistical multiplexing. Accordingly, we investigate the worst case
scenarios in a statistical multiplexer. We evaluate the upper bounds on the probabilities
of buffer overflow in a multiplexer, and data loss of an input stream. It is
found that in networks without traffic control, simply controlling the utilisation of
a multiplexer does not improve the ability to guarantee performance. Instead, the
availability of buffer capacity and the degree of correlation among the input traffic
dominate the effect on the performance of loss.
The leaky bucket mechanism has been proposed to prevent ATM networks from
performance degradation due to congestion. We study the leaky bucket mechanism
as a regulation element that protects an input stream. We evaluate the optimal
parameter settings and analyse the worst case performance. To investigate its effectiveness,
we analyse the delay performance of a leaky bucket regulated multiplexer.
Numerical results show that the leaky bucket mechanism can provide well-behaved
traffic with guaranteed delay bound in the presence of misbehaving traffic.
Using the leaky bucket mechanism, a general strategy based on burstiness characterisation,
called the LB-Dynamic policy, is developed for packet scheduling.
This traffic control strategy is closely related to the allocation of both bandwidth
and buffer in each switching node. In addition, the LB-Dynamic policy monitors
the allocated network resources and guarantees the network performance of each
established connection, irrespective of the traffic intensity and arrival patterns of
incoming packets. Simulation studies demonstrate that the LB-Dynamic policy is
able to provide the requested service quality for heterogeneous traffic in integrated
broadband networks