现代信息网络技术
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– Example: The telephone network
Busy Resource reservation: Resources are always available when needed by call Drawbacks ? Advantages ?
10
A simple Telephone Network
4
What is an Information Network
Telephone network TV network Integrated Service Digital Network (ISDN) B-ISDN ATM DWDM Internet
– why Internet???
21
Enabling Technologies
Transatlantic Cable (1866) Telephone System Satellite Communications: Sputnik (1957) The UNIX Operation System Local Area Networks and Desktop Workstations The Personal Computer Communications Devices Telecommunications Standards
Internet Users Internet Users Internet bandwidth Telephone bandwidth WWW
a^x b^x c^x ax+b ? x^x
why?
Assumption: New killer application x^x
27
DNA
N
1 2 3
N
A
3
N N 3
Address Memory
Time slot interchange pattern held during entire call Multiple connections: Time multiplexed
14
More Notes
Stochastic process
– Packet switching
– If users are burst (on/off), then packet-switching is advantageous (Baran, 1965)
18
Packet Switching Alternatives
Virtual-circuit transport
Bandwidth efficiency: Statistical multiplexing
– Buffers smoothen peak traffic load
Address data
17
Why Statistically Share Resources
Save/make money Example: 1Mbps link; each user requires 100Kbps when transmitting; each user has data to send only 10% of the time.
22
ARPANET TEAM
23
The Time Line
1960s
1970s
ARPA (57), ARPANet (69)
telnet (72), ftp (73), TCP (74), UUCP (75), mail (77)
1980s
CSNET (81), Bitnet (81), TCP/IP (82), EGP (82), IAB (82), DNS(84), NSFnet (86), NNTP (86), CERT (88), RIPE (89), IETF (89) ISP (90), CIX (91), WAIS (91), WWW (91), NREN (91), ISOC (92), NIC (93), Mosaic (93), Commercial (95), Netscape (95), Java (95), VRML (95), IAHC (96), NGI (96)
28
猜想
互联网下一个革命性的应用的必要条件 是其用户数量具有以 X^X 速率增长的潜 力。
29
Modeling
A^x X^x
How to model the Chinese new year based on the telephone traffic from US to China?
– Queuing theory – Poisson Model
Nyquist Theorem
– 300-3,400 8K
Quatization
– 8 bit
Digital communication standard
– – – – 64K E1 32x64K = 2.048M E2 8M E3 34M T1 24x64K = 1.5M T3 45M
– Saving of more than 31,000 km of links
11
Signaling Systems
随路信令
– 中国一号信令
s
s
s
共路信令
– 七号信令
s
s
s
12
Circuit Switching: Space division switch
Switching fabric
Control
5
பைடு நூலகம்
Network Evolutions
通信网 电话网数字化 模拟电话 步进交换 纵横交换 程控交换 N-ISDN ATM B-ISDN 计算机网 异构机互联 RS-232 LAN SNA IPX TCP/IP OSI
6
Evolution Networks
From point-to-point connection ...
– US Department of Defense Advanced Research Projects Administration envisions what would become the ARPANet Project.
Official justification: create a communications network capable of surviving nuclear war Real reason: An ARPA administrator had 3 terminals on his desk connecting to 3 different timesharing systems and he thought this was stupid.
24
1990s
Internet 的里程碑
1969-1985 1974 1983 1986 1989/90 1990 1994 1995 1998
basic packet net research design first published first major development first router commercial service WWW commercial WWW NSFNET retires new IANA
25
Explosive Growth
10000000 1000000 100000 10000 1000 100 10 1 69 84 89 92 95
1969 Host
1984 1989 1992 1995
4 1,024 159,000 1,136,000 9,472,000
26
Rate Game
15
Packet Switching
Data entering network divided into small chunks called packets Packets traversing a network share network resources with other packets Demand for resources may exceeded resources available: contention
现代信息网络技术
(01) 现状和定义
李星 (2004.02)-(2004.07)
1
Course Goal
Learn design and implementation of Internet (protocols, services and applications) Both theory and practice Comparison with traditional communication networks Case study: Learn through examples A fun, interactive learning experience
– Queuing (waiting) for resources
Statistical sharing of resources
16
Packet Switching: A closer look
Objective
– High utilization of communication links
Datagram transport
19
History
通信网 50 60 70
程控 X.25
80
ISDN
90
ATM
00
SDH DWDM
计算机网 50 60
分组交换
70
ARPANET
80
TCP/IP
OSI IPX
90
WWW
00
IPv6
20
Internet - The Beginning
Fall, 1968
2
Arrangements (1)
1、 现状和定义 2、 网络体系结构 3、 网络层分析,网络设计,地址分配,拓扑设计 4、 内部路由协议 5、 外部路由协议 6、 物理层和链路层 7、 传输层协议 8、 应用举例 VoIP, MLPS 9、 网络管理
3
Arrangements (2)
10、 网络安全 11、 政策性路由 12、 交换中心 13、 服务质量控制, MLPS, VoIP 14、 multicast 15、 网络电话 16、 移动IP 17、 IPv6 18、 新的应用
– Circuit-switching
Given each called 100 Kbps capacity Can support 10 callers
With 35 ongoing calls, probability that 10 or more callers are simultaneously active is less than 0.0004 Can support many more callers with small probability of contention.
7
Evolution Networks
To shared links
8
Evolution Networks
To store-and-forward networks A 1 2 3 60 60 1 2 B C
3
Time
9
Circuit Switching
All resources needed by a call (session) dedicated to that call for its duration.
Group of 10 lines of 1000 m each
S
S
S
Three building blocks
– 100 phone per building
100 telephone sets in each building
Saving achieved by connecting the telephones via switched instead of with point-to-point
Connections held during entire call Multiple connections: space multiplexed
13
Circuit Switching: Time division switch
Slot Memory
1 frame slot 2 3
M
1
2
N 1
Busy Resource reservation: Resources are always available when needed by call Drawbacks ? Advantages ?
10
A simple Telephone Network
4
What is an Information Network
Telephone network TV network Integrated Service Digital Network (ISDN) B-ISDN ATM DWDM Internet
– why Internet???
21
Enabling Technologies
Transatlantic Cable (1866) Telephone System Satellite Communications: Sputnik (1957) The UNIX Operation System Local Area Networks and Desktop Workstations The Personal Computer Communications Devices Telecommunications Standards
Internet Users Internet Users Internet bandwidth Telephone bandwidth WWW
a^x b^x c^x ax+b ? x^x
why?
Assumption: New killer application x^x
27
DNA
N
1 2 3
N
A
3
N N 3
Address Memory
Time slot interchange pattern held during entire call Multiple connections: Time multiplexed
14
More Notes
Stochastic process
– Packet switching
– If users are burst (on/off), then packet-switching is advantageous (Baran, 1965)
18
Packet Switching Alternatives
Virtual-circuit transport
Bandwidth efficiency: Statistical multiplexing
– Buffers smoothen peak traffic load
Address data
17
Why Statistically Share Resources
Save/make money Example: 1Mbps link; each user requires 100Kbps when transmitting; each user has data to send only 10% of the time.
22
ARPANET TEAM
23
The Time Line
1960s
1970s
ARPA (57), ARPANet (69)
telnet (72), ftp (73), TCP (74), UUCP (75), mail (77)
1980s
CSNET (81), Bitnet (81), TCP/IP (82), EGP (82), IAB (82), DNS(84), NSFnet (86), NNTP (86), CERT (88), RIPE (89), IETF (89) ISP (90), CIX (91), WAIS (91), WWW (91), NREN (91), ISOC (92), NIC (93), Mosaic (93), Commercial (95), Netscape (95), Java (95), VRML (95), IAHC (96), NGI (96)
28
猜想
互联网下一个革命性的应用的必要条件 是其用户数量具有以 X^X 速率增长的潜 力。
29
Modeling
A^x X^x
How to model the Chinese new year based on the telephone traffic from US to China?
– Queuing theory – Poisson Model
Nyquist Theorem
– 300-3,400 8K
Quatization
– 8 bit
Digital communication standard
– – – – 64K E1 32x64K = 2.048M E2 8M E3 34M T1 24x64K = 1.5M T3 45M
– Saving of more than 31,000 km of links
11
Signaling Systems
随路信令
– 中国一号信令
s
s
s
共路信令
– 七号信令
s
s
s
12
Circuit Switching: Space division switch
Switching fabric
Control
5
பைடு நூலகம்
Network Evolutions
通信网 电话网数字化 模拟电话 步进交换 纵横交换 程控交换 N-ISDN ATM B-ISDN 计算机网 异构机互联 RS-232 LAN SNA IPX TCP/IP OSI
6
Evolution Networks
From point-to-point connection ...
– US Department of Defense Advanced Research Projects Administration envisions what would become the ARPANet Project.
Official justification: create a communications network capable of surviving nuclear war Real reason: An ARPA administrator had 3 terminals on his desk connecting to 3 different timesharing systems and he thought this was stupid.
24
1990s
Internet 的里程碑
1969-1985 1974 1983 1986 1989/90 1990 1994 1995 1998
basic packet net research design first published first major development first router commercial service WWW commercial WWW NSFNET retires new IANA
25
Explosive Growth
10000000 1000000 100000 10000 1000 100 10 1 69 84 89 92 95
1969 Host
1984 1989 1992 1995
4 1,024 159,000 1,136,000 9,472,000
26
Rate Game
15
Packet Switching
Data entering network divided into small chunks called packets Packets traversing a network share network resources with other packets Demand for resources may exceeded resources available: contention
现代信息网络技术
(01) 现状和定义
李星 (2004.02)-(2004.07)
1
Course Goal
Learn design and implementation of Internet (protocols, services and applications) Both theory and practice Comparison with traditional communication networks Case study: Learn through examples A fun, interactive learning experience
– Queuing (waiting) for resources
Statistical sharing of resources
16
Packet Switching: A closer look
Objective
– High utilization of communication links
Datagram transport
19
History
通信网 50 60 70
程控 X.25
80
ISDN
90
ATM
00
SDH DWDM
计算机网 50 60
分组交换
70
ARPANET
80
TCP/IP
OSI IPX
90
WWW
00
IPv6
20
Internet - The Beginning
Fall, 1968
2
Arrangements (1)
1、 现状和定义 2、 网络体系结构 3、 网络层分析,网络设计,地址分配,拓扑设计 4、 内部路由协议 5、 外部路由协议 6、 物理层和链路层 7、 传输层协议 8、 应用举例 VoIP, MLPS 9、 网络管理
3
Arrangements (2)
10、 网络安全 11、 政策性路由 12、 交换中心 13、 服务质量控制, MLPS, VoIP 14、 multicast 15、 网络电话 16、 移动IP 17、 IPv6 18、 新的应用
– Circuit-switching
Given each called 100 Kbps capacity Can support 10 callers
With 35 ongoing calls, probability that 10 or more callers are simultaneously active is less than 0.0004 Can support many more callers with small probability of contention.
7
Evolution Networks
To shared links
8
Evolution Networks
To store-and-forward networks A 1 2 3 60 60 1 2 B C
3
Time
9
Circuit Switching
All resources needed by a call (session) dedicated to that call for its duration.
Group of 10 lines of 1000 m each
S
S
S
Three building blocks
– 100 phone per building
100 telephone sets in each building
Saving achieved by connecting the telephones via switched instead of with point-to-point
Connections held during entire call Multiple connections: space multiplexed
13
Circuit Switching: Time division switch
Slot Memory
1 frame slot 2 3
M
1
2
N 1