modeling and simulation of a video-on-demand network implementing adaptive source-level ...

97 Pages·1998·0.52 MB·English

MODELING AND SIMULATION OF A VIDEO-ON-DEMAND
NETWORK IMPLEMENTING ADAPTIVE SOURCE-LEVEL
CONTROL AND RELATIVE RATE MARKING FLOW CONTROL
FOR THE AVAILABLE BIT RATE SERVICE
by
Elvin Lattis Taylor, Jr.
Thesis submitted to the Faculty of the
Virginia Polytechnic Institute and State University
in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE
in
Electrical Engineering
Scott F. Midkiff, Chair
Nathaniel J. Davis, IV
Charles J. Parry
December, 1997
Blacksburg, Virginia
Keywords: Video-on-Demand, Traffic Management, High-speed Networking
Copyright 1997, Elvin Lattis Taylor, Jr.
MODELING AND SIMULATION OF A VIDEO-ON-DEMAND
NETWORK IMPLEMENTING ADAPTIVE SOURCE-LEVEL
CONTROL AND RELATIVE RATE MARKING FLOW CONTROL
FOR THE AVAILABLE BIT RATE SERVICE
by
Elvin Lattis Taylor, Jr.
Scott F. Midkiff, Committee Chair
Electrical Engineering
(ABSTRACT)
The Available Bit Rate (ABR) service class for the Asynchronous Transfer Mode (ATM)
protocol was originally designed to manage data traffic. ABR flow control makes no
guarantees concerning cell transfer delay or cell delay variation. A closed-loop feedback
mechanism is used for traffic management. To use this class of service for video transport,
the video source will accept feedback from the network and adapt its source rate based on
this status information. The objective of this research is to assess the ability of the ATM
ABR service class to deliver Moving Picture Experts Group version 1 (MPEG-1) video.
Three approaches to source-level control are compared: (i) arbitrary loss or no control
method, (ii) selective discard of MPEG B-pictures, and (iii) selective discard of MPEG B-
and P-pictures. Performance is evaluated based on end-to-end delay, congested queue
occupancy levels, network utilization, and jitter. A description of the investigation,
assumptions, limitations, and results of the simulation study are included.
Acknowledgments
I would like to thank my advisor Dr. Scott F. Midkiff for his advice, patience, and
commitment to excellence during this research endeavor, including the writing of this
thesis. I want to thank committee members Drs. Nathaniel J. Davis and Charles J. Parry
for their time and cooperation in this study.
I want to thank the National Science Foundation Graduate Research Fellowship Program
for supporting this work.
I would like to thank Farooq-e-Azam, Scott Harper, Rhett Hudson, and David Lee for
help with solving UNIX and OPNET problems.
I want to thank my parents Elvin L. Taylor, Sr. and Joyce W. Taylor and my sister
Michelle R. Taylor for their love, encouragement, and support.
I want to thank Cheryl D. Earle, Jeff Earley, Edward McPherson, and James Moore III for
their support.
I want to thank O. Rose for making publicly available the MPEG data sets used in this
study. Data sets are available via anonymous FTP to
ftp-info3.informatik.uni-wuerzburg.de in the /pub/MPEG/ directory.
Finally, I want to thank God who has allowed me to triumph through patience and
perseverance [Philippians 4:13].
iii
Table of Contents
Abstract.................................................................................................................ii
Acknowledgments..................................................................................................iii
Table of Contents...................................................................................................iv
List of Figures........................................................................................................vii
List of Tables.........................................................................................................ix
Chapter 1. Introduction.......................................................................................1
1.1 Research Objectives..........................................................................................1
1.2 Thesis Organization..........................................................................................3
Chapter 2. Communications Networks Overview...............................................5
2.1 Historical Highlights in Communications...........................................................5
2.1.1 The T1 Carrier...............................................................................................5
2.1.2 Optical Fiber Medium and Packet-Switching..................................................5
2.1.3 Integrated Services Digital Network..............................................................5
2.1.4 Broadband Integrated Services Digital Network.............................................5
2.1.5 Synchronous Optical NETwork and Synchronous Digital Hierarchy...............7
2.2 Asynchronous Transfer Mode...........................................................................7
2.2.1 ATM Protocol Reference Model....................................................................8
2.2.1.1 Physical Layer.............................................................................................8
2.2.1.2 ATM Layer.................................................................................................9
2.2.1.3 ATM Adaptation Layer...............................................................................12
2.3 Summary..........................................................................................................14
Chapter 3. Bandwidth Management...................................................................15
3.1 Quality of Service Traffic Contract...................................................................15
3.1.1 Contract Parameters......................................................................................15
3.1.2 Service Categories.........................................................................................17
3.1.2.1 Real-Time Traffic.......................................................................................17
3.1.2.2 Non-Real-Time Traffic................................................................................18
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3.2 Switch Mechanisms..........................................................................................19
3.3 Summary..........................................................................................................20
Chapter 4. Video Compression...........................................................................22
4.1 Joint Photographic Experts Group....................................................................22
4.2 H.261...............................................................................................................23
4.3 Moving Picture Experts Group.........................................................................23
4.4 Adaptive Video Compression...........................................................................24
4.4.1 Methods Applicable To Any Algorithm..........................................................25
4.4.2 Methods Applicable To MPEG......................................................................25
4.5 Summary..........................................................................................................26
Chapter 5. Experimental Design and Implementation .....................................28
5.1 Experimental Setup ..........................................................................................28
5.2 Response Variables...........................................................................................29
5.3 Experimental Factors........................................................................................29
5.4 Model Description............................................................................................29
5.4.1 Network Level...............................................................................................30
5.4.2 Node Level....................................................................................................31
5.4.2.1 STARTx10 Node Model.............................................................................31
5.4.2.2 CELL_GENn Node Model.........................................................................32
5.4.2.3 TRAF_MGR_SRCn Node Model...............................................................32
5.4.2.4 BURSTY_SRC Node Model......................................................................32
5.4.2.5 BURSTY_SINK Node Model....................................................................33
5.4.2.6 TRAF_MGR_SW_L Node Model..............................................................33
5.4.2.7 TRAF_MGR_SW_R Node Model..............................................................35
5.4.2.8 TRAF_MGR_DESTn Node Model.............................................................36
5.4.2.9 CELL_SINKn Node Model........................................................................37
5.4.3 Process Model Level......................................................................................37
5.4.3.1 STARTx10 Process Model.........................................................................38
5.4.3.2 TRAF_MGR_SRCn Process Model............................................................39
5.4.3.3 CELL_GENn Process Model......................................................................45
v
5.4.3.4 ACP_FIFO Process Model..........................................................................47
5.4.3.5 TRAF_MGR_DEST Process Model...........................................................49
5.4.3.6 CELL_SINK Process Model.......................................................................50
5.5 Verification and Validation...............................................................................51
5.5.1 Verification Techniques.................................................................................52
5.5.2 Validation Methods.......................................................................................52
5.6 Summary..........................................................................................................53
Chapter 6. Performance Results.........................................................................54
6.1 Simulation Performance....................................................................................54
6.2 Parameter Settings............................................................................................54
6.2.1 Trace Data.....................................................................................................54
6.2.2 Backbone Data Rate......................................................................................55
6.2.3 Bursty Source Parameters..............................................................................55
6.2.4 Network Congestion Points and Queue Congestion Thresholds.....................57
6.3 Analysis of Source Level Control Methods.......................................................57
6.3.1 Effects on End-to-End Delay.........................................................................58
6.3.2 Effects on Congested Queue Occupancy........................................................62
6.3.3 Effects on Network Backbone Utilization......................................................66
6.3.4 Variation in Delay..........................................................................................70
6.3.5 Distribution of Delay .....................................................................................74
6.4 Summary..........................................................................................................77
Chapter 7. Conclusions........................................................................................80
7.1 Summary of Research.......................................................................................80
7.2 Conclusions from Analysis................................................................................81
7.3 Recommendations for Future Research.............................................................81
References..............................................................................................................82
Appendix. ITU-T and ATM Forum........................................................................87
Vita........................................................................................................................88
vi
List of Figures
2.1 ATM Cell Format.............................................................................................7
2.2 ATM Protocol Architecture..............................................................................9
2.3 ATM Cell Header Format.................................................................................10
2.4 ATM Connection Identifier...............................................................................11
4.1 Representation of H.261 Video Coding Sequence............................................23
4.2 Representation of MPEG Video Coding Sequence...........................................24
5.1 Model of Simulated Network............................................................................28
5.2 Network Model................................................................................................30
5.3 Node Model of STARTx10..............................................................................31
5.4 Node Model of Cell Generator..........................................................................32
5.5 Node Model for TRAF_MGR_SRCn................................................................32
5.6 Node Model of BURSTY_SRC........................................................................33
5.7 Node Model of BURSTY_SINK......................................................................33
5.8 Node Model of TRAF_MGR_SW_L................................................................34
5.9 Node Model of TRAF_MGR_SW_R................................................................36
5.10 Node Model of TRAF_MGR_DEST..............................................................37
5.11 Node Model of CELL_SINKn........................................................................37
5.12 STARTx10 Process Model.............................................................................39
5.13 Process Model of TRAF_MGR_SRCn............................................................39
5.14 Process Model of CELL_GENn......................................................................45
5.15 Process Model of ACP_FIFO.........................................................................47
5.16 Process Model of TRAF_MGR_DEST...........................................................50
5.17 Process Model of CELL_SINK......................................................................51
6.1 Video Sequence Segmentation..........................................................................56
6.2 Drop Mode Off, End-to-End Delay, 200-Cell Queue Capacity..........................58
6.3 Drop B-Pictures Only, End-to-End Delay, 200-Cell Queue Capacity.................59
6.4 Drop B- and P-Pictures, End-to-End Delay, 200-Cell Queue Capacity..............59
6.5 Drop Mode Off, End-to-End Delay, 300-Cell Queue Capacity..........................60
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6.6 Drop B-Pictures Only, End-to-End Delay, 300-Cell Queue Capacity.................61
6.7 Drop B- and P-Pictures, End-to-End Delay, 300-Cell Queue Capacity..............61
6.8 Drop Mode Off, Queue Depth, 200-Cell Queue Capacity..................................62
6.9 Drop B-Pictures Only, Queue Depth, 200-Cell Queue Capacity........................63
6.10 Drop B- and P-Pictures, Queue Depth, 200-Cell Queue Capacity....................63
6.11 Drop Mode Off, Queue Depth, 300-Cell Queue Capacity................................64
6.12 Drop B-Pictures Only, Queue Depth, 300-Cell Queue Capacity......................65
6.13 Drop B-and P-Pictures, Queue Depth, 300-Cell Queue Capacity.....................65
6.14 Drop Mode Off, Backbone Utilization, 200-Cell Queue Capacity....................66
6.15 Drop B-Pictures Only, Backbone Utilization, 200-Cell Queue Capacity..........67
6.16 Drop B- and P-Pictures, Backbone Utilization, 200-Cell Queue Capacity........67
6.17 Drop Mode Off, Backbone Utilization, 300-Cell Queue Capacity....................68
6.18 Drop B-Pictures Only, Backbone Utilization, 300-Cell Queue Capacity..........69
6.19 Drop B- and P-Pictures, Backbone Utilization, 300-Cell Queue Capacity........69
6.20 Drop Mode Off, Jitter, 200-Cell Queue Capacity............................................71
6.21 Drop B-Pictures Only, Jitter, 200-Cell Queue Capacity...................................71
6.22 Drop B- and P-Pictures, Jitter, 200-Cell Queue Capacity................................72
6.23 Drop Mode Off, Jitter, 300-Cell Queue Capacity............................................73
6.24 Drop B-Pictures Only, Jitter, 300-Cell Queue Capacity...................................73
6.25 Drop B- and P-Pictures, Jitter, 300-Cell Queue Capacity................................74
6.26 Drop Mode Off, Frequency, 200-Cell Queue Capacity....................................75
6.27 Drop B-Pictures Only, Frequency, 200-Cell Queue Capacity...........................75
6.28 Drop B- and P-Pictures, Frequency, 200-Cell Queue Capacity........................76
6.29 Drop Mode Off, Frequency, 300-Cell Queue Capacity....................................76
6.30 Drop B-Pictures Only, Frequency, 300-Cell Queue Capacity...........................77
6.31 Drop B- and P-Pictures, Frequency, 300-Cell Queue Capacity........................77
viii
List of Tables
2.1 ATM Service Classes........................................................................................13
3.1 ATM Service Category Attributes ....................................................................19
5.1 NI and CI Bit Settings and Their Associated Actions........................................40
5.2 Validation Methods..........................................................................................52
6.1 Summary Statistics...........................................................................................70
ix
Chapter 1. Introduction
The Broadband Integrated Services Digital Network (B-ISDN) concept is a world-wide
effort to merge data1 (packet-switched), voice (circuit-switched), and video (e.g., cable
television) networks [LAPO94]. This move to produce a single network capable of
providing services for computer communications, telecommunications, and video
delivery, has been widely accepted. The Asynchronous Transfer Mode (ATM) has been
chosen as the connection-oriented, cell-based, switching and (de)multiplexing method for
B-ISDN. Of the three services mentioned above, providing video service, such as video-
on-demand, video-conferencing, and real-time broadcasts, is the most challenging because
of its high bandwidth requirements and fixed delay bounds. To handle video service,
ATM designates the Constant Bit Rate (CBR) and the Variable Bit Rate (VBR) service
classes. These service categories guarantee strict contract requirements, agreed to by the
source and the network, before the network establishes the connection.
The Available Bit Rate (ABR) service class, which was originally designed to handle data
traffic, meets less stringent requirements. The ABR class makes no guarantees concerning
cell transfer delay or cell delay variation. A closed-loop feedback mechanism is used for
traffic management. To use this class for video service, however, requires that the video
source interact with the network. More specifically, the video source must accept
feedback from the network and adapt its source rate based on this status information. If
the network status indicates congestion, then the source must lower its rate.
1.1 Research Objective
Previous research in ABR flow control includes [TSE96], [ZUKE97], [WALT96], and
[GUPT95]. In [TSE96], the authors evaluate the performance and fairness of the Explicit
Forward Congestion Indication (EFCI). Multiple ABR source-destination pairs transport

1 In this thesis, data refers to computer network traffic such as electronic mail or file transfers.
1