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Performance evaluation of hybrid buffer ATM switch He, Yue
Abstract
Buffer management and cell scheduling are the most important factors affecting the design of packet switching architectures for ATM networks. Buffering is the major resource that dominates both the cost and performance of ATM switch fabrics. Buffer management is required whenever the instantaneous cell arrival rate at a switch output is higher than the output link rate. This thesis presents a hybrid buffer ATM switch architecture in which the buffer management scheme is realized by dedicated output buffers and a shared buffer. A new approach based on queue tail management, as well as distributed priority scheduling is incorporated in the proposed switch design. The proposed scheme aims at enhancing the performance of ATM switches by maintaining the head cells of logical output queues in relatively short dedicated output buffers, while maintaining the long tails of overflowing queues in a shared pool managed by a more intelligent buffer management unit. Under this scheme higher priority (or delay-sensitive) cells can be forwarded immediately to the output buffers potentially blocking some lower priority (but loss-sensitive) cells from advancing into the output buffers. If the shared buffer is full, then a suitable push-out scheme is employed. The output buffers employ a distributed priority scheduling technique for sending cells to output links. The proposed scheme is capable of handling multipriority traffic and of satisfying the QoS requirements of each class using a very simple architectural scheme with simplified distributed control policies compared to other schemes previously proposed. The hybrid buffer switch performance is evaluated using discrete time queueing theory and using simulation. We provide detailed analysis of the buffer management scheme by decomposing the complex partial sharing buffer analysis into an equivalent queueing problem. The thesis provides semi-closed form expressions for various performance measures. The discrete time queueing model is verified by simulation. The computation complexity of the queueing model is much smaller than that of similar models in the literature. The switch performance under multi-class traffic is critical to the network operation because real-time and non-real-time traffic demands different "quality of service" (QOS) regarding delay jitter and cell loss rate. For efficient buffer management, a simple two-class priority scheme is implemented in the output buffers to minimize cell delay and delay jitter for the delaysensitive (or real-time) traffic. A simulation package is developed and applied to evaluate the hybrid buffering switch under two-class (loss-sensitive and delay-sensitive) traffic using two different hybrid scheduling and buffer management polices. The extensive simulation results indicate that the QoS requirements for both traffic classes can be easily met by appropriately dimensioning the hybrid priority scheduling and buffer management policies. The hybrid distributed buffer control provides for flexible scheduling and keeps the hardware implementation cost lower than other switch architectures.
Item Metadata
Title |
Performance evaluation of hybrid buffer ATM switch
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1996
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Description |
Buffer management and cell scheduling are the most important factors affecting the design
of packet switching architectures for ATM networks. Buffering is the major resource that
dominates both the cost and performance of ATM switch fabrics. Buffer management is required
whenever the instantaneous cell arrival rate at a switch output is higher than the output link rate.
This thesis presents a hybrid buffer ATM switch architecture in which the buffer management
scheme is realized by dedicated output buffers and a shared buffer. A new approach based on
queue tail management, as well as distributed priority scheduling is incorporated in the proposed
switch design. The proposed scheme aims at enhancing the performance of ATM switches by
maintaining the head cells of logical output queues in relatively short dedicated output buffers,
while maintaining the long tails of overflowing queues in a shared pool managed by a more
intelligent buffer management unit. Under this scheme higher priority (or delay-sensitive) cells
can be forwarded immediately to the output buffers potentially blocking some lower priority (but
loss-sensitive) cells from advancing into the output buffers. If the shared buffer is full, then a
suitable push-out scheme is employed. The output buffers employ a distributed priority scheduling
technique for sending cells to output links. The proposed scheme is capable of handling multipriority
traffic and of satisfying the QoS requirements of each class using a very simple architectural
scheme with simplified distributed control policies compared to other schemes previously
proposed.
The hybrid buffer switch performance is evaluated using discrete time queueing theory
and using simulation. We provide detailed analysis of the buffer management scheme by decomposing the complex partial sharing buffer analysis into an equivalent queueing problem.
The thesis provides semi-closed form expressions for various performance measures. The discrete
time queueing model is verified by simulation. The computation complexity of the queueing
model is much smaller than that of similar models in the literature.
The switch performance under multi-class traffic is critical to the network operation
because real-time and non-real-time traffic demands different "quality of service" (QOS) regarding
delay jitter and cell loss rate. For efficient buffer management, a simple two-class priority
scheme is implemented in the output buffers to minimize cell delay and delay jitter for the delaysensitive
(or real-time) traffic. A simulation package is developed and applied to evaluate the
hybrid buffering switch under two-class (loss-sensitive and delay-sensitive) traffic using two
different hybrid scheduling and buffer management polices. The extensive simulation results
indicate that the QoS requirements for both traffic classes can be easily met by appropriately
dimensioning the hybrid priority scheduling and buffer management policies. The hybrid distributed
buffer control provides for flexible scheduling and keeps the hardware implementation cost
lower than other switch architectures.
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Extent |
3069973 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-03-09
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0064805
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1997-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.