Transcript CSE 245 Computer Networks and Data Communicatrion

CMPT 371
Data Communications and
Networking
Fall 2004
Outline
 Course information
 What is network?
 A brief introduction to the Internet’s
 past
 present
 Summary
2
Course Information
 Instructor:
 Jiangchuan (JC) LIU
Room 10826, Applied Science Building
 E-mail: [email protected]
Tel: 604-291-4336
 Office Hours: TBD (Wed afternoon ?)
 E-mail is the best way to communicate with me
 TA(s)

Zhengbing Bian ( [email protected] )
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Course Information
 Time & Venue
 Wednesday 17:30-20:20pm
 RC Brown 8100
 There will be one or two breaks
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Course Information
 Textbook
 Computer Networking: A Top-Down
Approach Featuring the Internet, by
Kurose and Ross
 Reference books
 Computer Networks,
4/e by Andrew Tanenbaum
 Data and Computer communications,
7th edition , William Stallings, Prentice
Hall, 2003
 And more (see Web)
 Resource
 Home page
• www.cs.sfu.ca/~jcliu/cmpt371
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Course Information
 Textbook
 Computer Networking: A Top-Down
Approach Featuring the Internet, by
Kurose and Ross
 Why using this book ?
 New content – this is a fast-changing
area
 But more important, new structure and
target
Top-down
Featuring the Internet
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What Are the Goals Of This Course?
 Understand how Internet works
 Its philosophy
 Its protocols and mechanisms
 Learn network programming
 Have fun!
 Are you happy with no Internet access in your life ?
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What Will We Cover? (Tentative schedule)
 Introduction (1.5 – 2 weeks)
 Internet architecture and design philosophy
 Applications (2-3 weeks)
 HTTP, Email, DNS
 transport services (2-3 weeks)
 reliability; congestion control; transport
protocols: TCP/UDP
 network services (2-3 weeks)
 routing; network protocols: IP/IPv6
 link and physical layers (2-3 weeks)
 multiple access; Ethernet, FDDI, hubs and
bridges
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What Do You Need To Do?
 Your prerequisites
 algorithms: e.g. shortest path algorithms
 programming: C/C++, Java
 basic concepts of operating systems
 Your workload
 reading assignment for every lecture
 homework assignments
• 3 written assignments
• 2 programming projects

one mid-term exam, and one final exam
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Grading (tentative)
Written Homework
10%
Programming work
15%
Mid-term exam
30%
Final exam
45%
 Class participation
 More important is what you learn than the grades
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Questions?
Outline
 Course information
 What is network?
 A brief introduction to the Internet’s
 past
 present
 Summary
12
Q: What is Network?
 Telephone network
 Dialup
 Local area network
 Internet
 Mobile phone
…
Nodes -- Interconnected
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Why Internet ?
 The most successful network
 Open
 Heterogeneous
 Simple network, complex end-terminals
• End-to-end argument
 How about other networks?
 Telephone
 Mobile phone
 Wireless LAN
 Cable TV
 IP convergence…
 And, about the authors of the text book
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Course Information
 Textbook
 Computer Networking: A Top-Down
Approach Featuring the Internet, by
Kurose and Ross
 Reference books
 Computer Networks,
4/e by Andrew Tanenbaum
 Data and Computer communications,
7th edition , William Stallings, Prentice
Hall, 2003
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Motivation: Communication
 Need some common interface to
communicate  network protocol
 A->B: Hi
 B->A: Hi
 A->B: What time is it ?
 B->A: 1:00pm
 What if no protocol…
 Woi kx ioa nio ?
 #@!>? …
…
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An Example: Simple Mail
Transfer Protocol (SMTP)
 Scenario
 Email client: Outlook, TheBat, NetscapeMail …
 Email server: in Unix, Windows …
 Messages from a client to a mail server
 HELO
 MAIL FROM: <email address>
mail
 RCPT TO: <email address>
server
 DATA
<This is the text (mail body) end
with a line with a single .>
 QUIT
SMTP
 Messages from a mail server to a client
 status code
– 1xx - Informative message
mail
– 2xx - Command ok
server
– 3xx - Command ok so far, send the rest of it.
– 4xx - Command was correct, but couldn't be
performed for some reason.
– 5xx - Command unimplemented, or incorrect, or a
serious program error occurred.

mail body
user
agent
outgoing
message queue
user mailbox
user
agent
SMTP
SMTP
POP3,
IMAP
SMTP
user
agent
mail
server
user
agent
user
agent
user
agent
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Internet Standardization Process
 All standards of the Internet are published as RFC
(Request for Comments)



but not all RFCs are Internet Standards !
available: http://www.ietf.org
Till this morning: RFC3099
 A typical (but not the only) way of standardization:
 Internet draft
 RFC
 Proposed standard
 Draft standard (requires 2 working implementations)
 Internet standard (declared by Internet Architecture
Board)
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Internet Standardization Process
 All standards of the Internet are published as RFC
(Request for Comments)



but not all RFCs are Internet Standards !
available: http://www.ietf.org
Till now: RFC3866
 A typical (but not the only) way of standardization:
 Internet draft
 RFC
 Proposed standard
 Draft standard (requires 2 working implementations)
 Internet standard (declared by Internet Architecture
Board)
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Outline
 Course information
 What is a network protocol?
 A brief introduction to the Internet’s
 past
 present
 Summary
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A Brief History of the Internet
 1957


USSR launches Sputnik, US formed Advanced Research Projects
Agency (ARPA) as a response
1968

Bolt Beranek and Newman, Inc. (BBN) was awarded Packet Switch
contract to build Interface Message Processors (IMPs) for
ARPANET
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A Brief History of the Internet
 1969

ARPANET commissioned: 4 nodes, 50kbps
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Initial Expansion of the ARPANET
Dec. 1969
July 1970
Apr. 1972
March 1971
Sep. 1972
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Multiple Networks
 1974: Initial design of TCP to connect multiple
networks
 1986: NSF builds NSFNET as backbone, links 6
supercomputer centers, 56 kbps; this allows an
explosion of connections, especially from
universities
 1987: 10,000 hosts
 1989: 100,000 hosts
WELCOME by Leonard Kleinrock …
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Web and Commercialization of the Internet
 1991: NSF lifts restrictions on the commercial use
of the Net; World Wide Web released
 1992: 1 million hosts
 Today: backbones run at 10Gbps, 100s millions
computers in 150 countries
 Internet history and Timeline

http://www.zakon.org/robert/internet/timeline/
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Growth of the Internet
in Terms of Number of Hosts
Number of Hosts on the 1,000,000,000
Internet:
100,000,000
Aug. 1981
213
10,000,000
Oct. 1984
1,024
1,000,000
Dec. 1987
28,174
100,000
10,000
Oct. 1990
313,000
1,000
Jul. 1993
1,776,000
100
Jul. 1996 19,540,000
10
Jul. 2000 93,047,000
1
Jul. 2002 162,128,493
1981 1984 1987 1990 1993 1996 1999 2002
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Internet Physical Infrastructure
Local/Regional
ISP
 Residential
Access



Modem
DSL
Cable modem
 Campus
network access



Ethernet
FDDI
Wireless
 Access to ISP,
Backbone
transmission


Local/Regional
ISP
Backbone:
National ISP
 Internet Service
T1/T3, OC-3, OC-12
ATM, SONET, WDM
Providers


Local/Regional/Natio
nal
They exchange
packets at Point of
Presence (POP)
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Local Access: ADSL
 Asymmetrical Digital Subscriber Line (ADSL)
 Telephone company’s solution to “last mile problem”
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Local Access: Cable Modems



Fiber node: 500 - 1K homes
Distribution hub: 20K - 40 K homes
Regional headend: 200 K - 400 K homes
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AT&T US Internet Backbone
From AT&T web site.
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Canadian 2G National Internet Backbone
From http://www.canarie.ca/canet4/connected/canet4_map.html
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AT&T Global Backbone IP Network
From http://www.business.att.com
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Web and Commercialization of the Internet
http://research.lumeta.com/ches/map/
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Killer applications - FTP
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Killer applications - Email
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Killer applications – WWW 1990-
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Killer applications – P2P 2000-
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Killer applications- what’s next ?
 Media streaming (Internet TV)
 E-commerce
 Online game
 …
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Summary
 Course information
 Network: nodes -> interconnected
 Protocol: format and the order of messages
exchanged, as well as the actions taken
 Internet: The past:



started as ARPANET: late 1960s
initial link bandwidth: 50 kbps
number of hosts: 4
 Internet: Current:
 number of hosts: grows at an exponential speed
July 2002 was about 162 millions
 backbone speed: 10 Gbps
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Practices
 Log into a Unix machine (or Windows)
 Read the manual of ping and traceroute,
and try them on a machine
1.
2.
% /bin/ping <machine_name>
% /usr/sbin/traceroute <machine_name>
 Look at the web sites of the routers you
see through traceroute
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