EITF25 Internet Techniques and Applications

EITF25 Internet Techniques and Applications

Stefan Höst E:3135b stefan.host@eit.lth.se

Internet, one view

Internet, another view

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Other views

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Objectives

•  Understanding of data communication networks •  Logical levels of communication

•  Physical

•  Network

•  Application

•  Security on Internet •  Search engines

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Course content?

•  11 lectures •  3 mandatory laboratory sessions •  Two hand in problem •  Home exam

Schedule of lectures (E:2311) Week Date Topic 1 30/10 13-15 Introduction

1 2/11 10-12 Physical layer

2 6/11 13-15 Data link

2 9/11 10-12 Network access

3 13/11 13-15 Wide Area Networks

3 16/11 10-12 Routing

4 20/11 13-15 Applications

4 23/11 10-12 Network management alt. Mobile networks

5 27/11 13-15 Web search

6 4/12 13-15 Network security

7 11/12 13-15 Repetition/Reserve 7

Laboratory exercises (E:)

Study week Topic

5 Protocols

6 World Wide Web --- WWW

7 Infrastructure and applications

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•  Two groups per week •  Signa up for groups on the web page •  Prepare before

Exercises

•  Recommended problems can be found on the web page

•  Question hours scheduled on the web page •  Friday 9/11 13-15 E:3139

•  …

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Course material

•  Two alternative books (sold by KFS)

•  Data Communications and Networking (5 Ed), B.A. Forouzan

•  Internet, M. Kihl and J. A. Andersson •  Slides published on web page •  Lab manual •  Exercises

Examination

•  Laboratory sessions •  Hand in problems

•  After study week 2 and 4

•  Home exam

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What is Internet?

•  How did it start? •  What is Internet today? •  How does it work?

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Data communication

After torches and smoke signals, the optical telegraph was invented in the 18th century.

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Data communication

Optical telegraphs evolved into electrical telegraphs, which quickly increased the available data communication speed and distance.

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Telephone networks

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The need for telephone networks became obvious in the late 19th century...

Basics of circuit switching

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Telephone networks

17 •  Late 1940: 350 000 operators at AT&T, 98% women

Basics of packet switching

18 Source: http://www.tcpipguide.com

Internet growth

•  1969 ARPANET •  Advanced Research Projects Agency Network

•  First packet switched network

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•  UCLA •  University of California, Los Angeles

•  SRI •  Stanford Research Institute

•  UCSB •  University of California, Santa Barbara

•  UTAH •  University of Utah

Internet growth

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Internet growth

•  1985 NSFNET replaces ARPANET •  Backbone based on 56kb/s links

•  1988 backbone complemented with 1.5Mb/s links •  1991

•  upgrade to 44Mb/s

•  600 000 hosts in 100 countries

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Internet growth

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•  Map of Internet 2003

•  Color coding according to continents

Internet growth

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•  Connection density

Connection technology

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Nielsen’s law

The end-user connectivity grows with 50% every year.

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Internet growth

Internet in numbers ≈2015: •  1 billion fixed connections •  >7 billion mobile connections •  15 billlion devices (twice the population) •  1 million minutes of video every second •  Total traffic close to 1Zbyte/year (Z=zetta=1021)

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Client/server paradigm

Most early applications were based on the client/server paradigm.

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Request

Reply

Telnet

Telnet was invented in 1969, and provided access to a remote terminal.

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TELNET, klient

Terminal driver

Network

TELNET, server

Local computer

Applications

Pseudoterminal driver

Email

•  Ray Tomlinson sent the first email in 1971 •  To separate a specific user on a host computer, he

used the @ sign. It was unused on the keyboard.

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Email

30 Source: http://www.tekguard.com

File Transfer Protocol (FTP)

•  FTP was devloped in 1971 •  It enabled file transfer between two computers.

31 Source: http://opcenter.cites.uiuc.edu

Internet protocol

•  In 1973, Robert E. Kahn and Vincent Cerf developed the ideas of an internetwork protocol that made it possible for hosts on different networks to communicate with each other.

•  The ideas defined the Transmission Control Protocol (TCP) protocol in 1974.

•  Later, some parts of the TCP protocol were moved to the Internet protocol (IP), creating the TCP/IP protocol suite.

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Basic idea of Kahn and Cerf’s internetworking

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NetworkNetwork

Network

§  Host identification (Addresses)

§  Forwarding of messages between networks (routing)

§  End-to-end reliability (error and flow control)

In the beginning

•  1978: First spam (by Gary Thuerk) •  1982: Scott Fahlman introduces :-) and :-( •  1985: lth.se registrerades •  1987: GIF •  1988: Internet worm

(by Robert Tappan Morris) •  1990: Internet service provider

(world.std.com) 34  Boston Museum of Science.

World wide web (www)

•  1990: Tim Berners-Lee developed •  HTTP (Hypertext Transfer Protocol)

•  HTML (Hypertext Markup Language)

•  1991 he wrote a first web browser •  1991 www goes public •  1990: http://info.cern.ch/ •  1991: The Trojan Coffee room pot

•  First webcam (real time images) 35

World wide web (www)

•  1993 NCSA Mosaic (1994 Netscape) •  1995 IE

•  1994: Pizza Hut first online webshop •  1994: Yahoo •  1995: AltaVista •  1997: AOL instant messanger •  1997: Sixdegrees.com (first modern social network) •  1997: Google.com

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And then came the explosion •  1999: Napster •  1999: Blogger •  2001: BitTorrent •  2001: Wikipedia •  2003: Skype •  2003: WordPress •  2004: Gmail •  2004: Flickr •  2005: YouTube •  2005: Facebook •  2006: Twitter •  2008: Spotify •  2009: Google Docs •  2009: (Dec): Angry Bird 37

•  1998: ADSL standard •  2001: UMTS service (3G) •  2005: VDSL2 standard •  2007: iPhone •  2007: Android •  2007: Amazone Kindle •  2009: First LTE service (4G) •  2010: iPad

Peer-to-peer paradigm

Several of the modern Internet applications are based on the Peer-to-peer (P2P) paradigm.

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Example: Skype

39 Source: http://www.technology-training.co.uk

Evolution of Internet usage (traffic volumes) seen from the users

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2007: 2011:

J. Li, A. Aurelius, V. Nordell, M. Du, Å. Arvidsson, M. Kihl: A five year perspective of traffic pattern evolution in a residential broadband access network Future Network & Mobile Summit 2012

Content distribution architectures

Media content is stored in back-end server clusters (cloud) and then distributed to clients when requested.

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Internet

Content Clients

Example:Live sport channel at TV4

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National ISPAccess network Modem

Speakers

Cache servers(http)

Production Transmission control

IP multicast network

EncodingEncryption Ingest servers Origin servers

(http)

PC / CE device (TV /

bluray)

Content Distribution

Network (CDN)Ingest servers

(http)

Performance challenges

•  Client/server archictures are usually deployed: •  Standardized protocols as HTTP are used.

•  Control of the material.

•  Client/server archtectures cause performance problems: •  Heavy traffic loads on network infrastructure (unicast

transmission).

•  Delays due to centralized data centers and overloaded access networks.

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One solution: P2P and caches (Spotify)

44 Source: http://www.csc.kth.se/~gkreitz/

Internet physical structure

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Internet physical structure

Sunet

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Nordunet

Internet logical structure

•  Applications •  MAIL, FTP, HTTP, SNMP, DNS, SSH

•  Networks •  TCP, UDP, IP, IPsec, Flooding, IPv4

•  Point to point connection •  PSK, FSK, Multiplexing, CRC, ALOHA

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Course objectives

•  Introduction to computer communication and networking, with focus on the Internet.

•  Digital communication

•  Network access

•  Internet protocols

•  Routing

•  Applications

•  Security

•  Web search

•  ”Hands-on” experience in laboratory sessions. 48