| Summary: | 博士 === 國立清華大學 === 資訊工程學系 === 86 === The significant improvement of communication technique tends
to integrate a diversity of services into one universal
transmission environment. The developments of the Broadband
Integrated Digital Services Network (B-ISDN) are to provide such
kind of transport of services with different bandwidth and
performance requirements. According to the membership involved
in the connection, the transmission services can be simply
divided into two categories: point-to-point (referred as
unicast) and point-to-multipoint (referred as multicast)
services. The researches on unicast switching system have
intensively studied in the last decades. To efficiently support
the multicast services, the multicast switching system will play
an important role in the future communication fields.
Multicast services represent the provision of connections that
transmit packets from one node to multiple nodes. The tasks
performed by the multicast switching system include duplication
and routing. According to the ways to perform these two tasks,
the multicast switching systems can be classified into two
categories: isolated multicast switching system and unified
multicast switching system. The main feature of the isolated
multicast switching system is distinctively divided the whole
multicast operation into copying and routing operations, and
both of them are performed by different interconnection networks
respectively. Such kinds of multicast switches are of advantages
to easily augment the multicasting capability to the unicast
switches by appending a copy network in the front of it. On the
other hand the unified multicast switches simultaneously perform
the copying and routing operations in the same network. The
treatments of the incoming cells are in a fair situation. The
performance requirements of the multicast services are
guaranteed. The isolated multicast switching system can be
further divided into two structures: cascaded multicast
switching system and multicast module attached switching system.
No matter what kind of multicast switching architectures is
considered, the design issues involved can be addressed as four
aspects: copy algorithms, multicast group number translations,
overflow control of duplication, and collision resolution for
the copy network. The multicast switching architectures
proposed in this dissertation include both kinds of fabrics. The
class of isolated multicast switching systems, including the
distributed copy network and the dilated multicast Banyan
network, are constructed by the idea of partial duplication that
divides the entire duplication operation into two sub-copy
processes: static copying process and dynamic copying process.
This division of duplication process results in reduction of the
loss rate and simplification of the maintenance for the
multicast connections. On the class of the unified multicast
switching system, the broadcast feature of the shared connected
bus in the Knockout switch is used to design a multicast
switching with the capability of duplication and routing in the
same network. The fair treatments of the multicast and unicast
cells reduce the delay needed to transmit the multicast ones. At
last, we present the other unified multicast switching
architecture based on multistage topology in this dissertation
and describe the advantages that this kind takes.
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