| Summary: | 碩士 === 國立中央大學 === 資訊及電子工程研究所 === 82 === This thesis focuses on the problems arising with the inter
-working unit ( or gateway) which connects a Distributed Queued
Dual Bus (DQDB) Metropolitan Area Network (MAN) with Broadband
Integrated Service Digital Network (B-ISDN) based on the
technique of Asynchronous Transfer Mode (ATM).The bandwidth
allocation for setting up a virtual connection between gateway
and ATM network is our main concern. The ATM network
architecture is based on a connection- oriented technique. As
to DQDB MAN, there are two methods for medium access. One is
Pre-Arbitrated (PA) access mode which supports isochronous
service and the other is Queued- Arbitrated (QA) access mode
which supports non-isochronous service. Although DQDB MAN may
provide connection-oriented data service based on QA access
mode which is expected to be a better solution in terms of
service quality and simplicity of implementation, however, it
has not been clearly specified yet. For the moment, the problem
we are concerned with is how to interconnect connectionless
DQQB MANs via connection-oriented ATM network and make the best
use of resources. In this thesis, we propose a new estimation
algorithm for connectionless DQDB MAN interworking with ATM to
estimate incoming traffic rate rapidly and accurately. This
results in low loss rate and minimal queueing delay in gateway
buffer compared with other schemes which have been proposed. In
addition, based on the knowledge of required bandwidth, we
propose a negotiation strategy for bandwidth allocation.
Simulation results show that the proposed scheme performs
better than others in most cases. Further, we present another
method which we called "confirmation mechanism" to achieve the
lowest cell loss rate for internetting DQDBs via B-ISDN under a
tolerable coverage of queueing delay.
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