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ATM (Asynchronous Transfer Mode) is the most promising
transfertechnology for implementing B-ISDN (Broadband Integrated
Service Digital Network). It supports applications with distinct
QoS requirements such as delay, jitter, and cell loss and with
distinct demands such as bandwidth and throughput. ATM Forum
defined a service class known as ABR (Available Bit Rate)
service to support data applications economically. Also an end-
to-end adaptive control mechanism called closed-loop rate-based
flow control is applied to this service. Hence the rate-based
flow control plays an important role for efficient traffic
management of ABR service in ATM networks. This thesis mainly
includes five parts which investigate the effect of the rate-
based flow control and design the new rate-based control scheme:
(I) a performance analysis of a rate-based flow control
mechanism under a fixed number of sources, (II) the effect of a
rate-based control mechanism under a variable number of sources,
(III) a performance analysis of a rate-based flow control
mechanism under burstiness at call and cell levels, (IV) the
interoperability of EFCI (Explicit Forward Congestion
Indication) and ER (Explicit Rate) switches, and (V) the dual
control problem of TCP over ABR services. Recently several
analyses and simulations have been conducted for rate-based
control schemes. However, some assumption of these analyses are
improper, including infinite buffer at the switch, a fixed
number of sources, and non-bursty greedy sources. Hence in the
thesis, we consider the case that buffer at the switch is
finite. Further, the condition of a variable number of sources
is examined. Finally we consider the case that the source
traffic is generated with a bursty behavior.We provide the
concept of "best area" which helps us to determine some
important parameters. Also we develop three enhancements,
namely, static threshold, dynamic threshold, and revised ICR
(Initial Cell Rate). These enhancements can reduce cell loss
probability and raise utilization for the realistic situation
where the new sources may arrive and the existing sources may
depart. The effect of burstiness at cell and call levels can be
observed. It isconfirmed analytically that the impact of
burstiness at the cell level is obviously more influential than
that at the call level. The research about interoperability of
various switch schemes shows some observations which are not
shown in the homogeneous environment. We understand that CMM
(Charny Max-Min) is better in the homogeneous and heterogeneous
environments and that ER switches should be placed at the
bottleneck, most critical point and near-source location.
Finally we suggest to implement the use-it-or-lose-it policy in
ABR flow control to alleviate the problems of unused high ACR
(Allowed Cell Rate) and switch queue underflow in the scenario
of TCP over ABR where there are two flow control mechanisms
working at the same time. These results provide much insight
into the effect of using the rate-based flow control.
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