Slides for Chapter 15:
Distributed Multimedia Systems
From Coulouris, Dollimore and Kindberg
Distributed Systems:
Concepts and Design
Edition 3, © Addison-Wesley 2001
Figure 15.1
A distributed multimedia system
Vid eo came ra
and mike
Local network
Local network
Wid e are a ga teway
Vid eo
server
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Digital
TV/radio
server
Figure 15.2
The window of scarcity for computing and communication resources
interactive
video
hig h-qua lity
aud io
ins uffi cie nt
reso urce s
scarce
reso urce s
abu ndan t
reso urce s
netwo rk
fil e acce ss
remo te
log in
198 0
199 0
200 0
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.3
Characteristics of typical multimedia streams
Data rate
(approximate)
Sample or frame
size
frequency
Telephone speech
64 kbps
8 bits
8000/sec
CD-quality sound
1.4 Mbps
16 bits 44,000/sec
Standard TV video
120 Mbps
up to 640 x 480
24/sec
(uncompressed)
pixels x 16 bits
Standard TV video
1.5 Mbps
variable
24/sec
(MPEG-1 compressed)
HDTV video
1000–3000 Mbps up to 1920 x 1080 24–60/sec
(uncompressed)
pixels x 24 bits
HDTV video
10–30 Mbps
variable 24–60/sec
MPEG-2 compressed)
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.4
Typical infrastructure components for multimedia applications
PC/works tati on
PC/works tati on
Win dow syste m
Camera
K
A
Codec
Micro phon es
Scre en
B
G
Codec
H
L
Mixer
Network
co nnectio ns
C
Vid eo fil e syste m
D
Codec
M
Vid eo
sto re
Win dow syste m
: mul time diastre am
Whi te b oxes re prese nt m edia process ing com pone nts,
man y of whi ch are i mple mented i n so ftware, includ ing:
co dec: co ding /decodi ngfil ter
mixer: sou nd-mi xi ngco mpon ent
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.5
QoS specifications for components of the application shown in Figure 15.4
Component
Latency
A
Interactive Low
B
H
K
L
Bandwidth
Out:
10 frames/sec, raw video
Camera
640x480x16 bits
Codec
In:
10 frames/sec, raw video
Out:
MPEG-1 stream
Mixer
In:
2 44 kbps audio
Out:
1 44 kbps audio
Window
In:
various
system
Out:
50 frame/sec framebuffer
Network
In/Out: MPEG-1 stream, approx.
connection
1.5 Mbps
Network
In/Out: Audio 44 kbps
connection
Loss rate
Zero
Interactive Very low
Interactive Low
Interactive Low
Interactive Very low
Resources required
10 ms CPU each 100 ms;
10 Mbytes RAM
1 ms CPU each 100 ms;
1 Mbytes RAM
5 ms CPU each 100 ms;
5 Mbytes RAM
1.5 Mbps, low-loss
stream protocol
44 kbps, very low-loss
stream protocol
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.6
The QoS manager’s task
Adm issi onco ntrol
QoS neg otia tion
Application components s pecify their QoS
requirements to QoS manager
Flo w spec.
QoS manager ev aluates new requirements
agains t the av ailable res ources.
Suffic ient?
Yes
Reserve the requested res ources
Resou rce con tract
Allow applic ation to proceed
Application runs w ith res ources as
per resourc e c ontract
No
Negotiate reduc ed res ource provision w ith applic ation.
Agreement?
Yes
No
Do not allow applic ation to proceed
Application notifies QoS manager of
increas ed res ource requirements
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.7
Traffic shaping algorithms
(a) L eaky bucket
(b) Toke n bu cket
Token gene rator
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.8
The RFC 1363 Flow Spec
Protocol version
Maximum transmission unit
Bandwidth:
Token bucket rate
Token bucket size
Maximum transmission rate
Delay:
Minimum delay noticed
Maximum delay variation
Loss sensitivity
Loss:
Burst loss sensitivity
Loss interval
Quality of guarantee
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.9
Filtering
Source
Targets
High bandwidth
Medium bandwidth
Low bandwidth
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Figure 15.10
Tiger video file server hardware configuration
Controller
low-bandwidth network
0
n+1
Cub 0
1
n+2
Cub 1
2
n+3
Cub 2
3
n+4
Cub 3
n
2n+1
Cub n
high-bandwidth
ATM switching network
video distribution to clients
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
Start/Stop
requests from clients
Figure 15.11
Tiger schedule
2
block service
time t
1
block play time T
0
slot 0
slot 1
slot 2
slot 3
slot 4
slot 5
slot 6
slot 7
viewer 4
free
free
viewer 0
viewer 3
viewer 2
free
viewer 1
state
state
state
state
Instructor’s Guide for Coulouris, Dollimore and Kindberg Distributed Systems: Concepts and Design Edn. 3
© Addison-Wesley Publishers 2000
state