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Computer/ Telecommunication Networks

Computer/ Telecommunication Networks. Sándor Laki ELTE-Ericsson Communication Networks Laboratory ELTE FI – Dep artment Of Information Systems lakis@elte.hu http://lakis.web.elte.hu

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Computer/ Telecommunication Networks

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  1. Computer/TelecommunicationNetworks Sándor Laki ELTE-Ericsson CommunicationNetworksLaboratory ELTE FI – Department Of Information Systems lakis@elte.hu http://lakis.web.elte.hu Basedontheslides of Laurent Vanbever.Furtherinspiration: Scott Shenker & Jennifer Rexford & PhillipaGill

  2. Hello! • Welcome to Computer Networks • Are you in the right classroom? • Okay, good. • Who am I? • Sándor Laki, PhD • Assistant Professor atDept. Of Information Systems • lakis@inf.elte.hu • Office: Southern Building, Room 2.506 • Office Hours: 10-11 Thursday, in room 2.506

  3. Why Take This Course? • How many of you have checked your e-mail, FB, text… • Today? • In the past hour? • Since I started talking?

  4. Computer networks are ubiquitous • Networks touch every part of our daily life • Web search • Social networking • Watching movies • Ordering merchandise • Wasting time

  5. Computer networks are ubiquitous • Networking is one of the most critical topics in CS • There would be no… • Big Data • Cloud • Apps or Mobile Computing • … without networks

  6. The Internet a reallyexcitingplace

  7. 17.1 billion

  8. 17.1 billion number of devices connected to Internet in 2016 (estimation*) *Cisco Visual Networking Index 2016—2021

  9. 27.1billion number of devices connected to Internet in 2021 (estimation*) *Cisco Visual Networking Index 2016—2021

  10. ~3 exabyte the daily total Internet traffic in 2016 (estimation*) [1EB = 1018Bytes = 1 000 000 000 000 000 000 Bytes] *Cisco Visual Networking Index 2017

  11. If = 1 Gigabyte

  12. ~ 1 exabyte

  13. ~9 exabyte the daily total Internet traffic in 2021 (estimation*) *Cisco Visual Networking Index 2017

  14. ~55% video traffic of the total Internet traffic in 2016 (estimation*) *Sandvine 2016 Global Internet Phenomena

  15. *Sandvine 2016 Global Internet Phenomena (https://www.sandvine.com/hubfs/downloads/archive/2016-global-internet-phenomena-report-latin-america-and-north-america.pdf)

  16. ~80% video traffic of the total Internet traffic in 2021 (estimation*) *Cisco Visual Networking Index 2017

  17. The other side…

  18. Internet traffic from/to Egypt in January 2011 *http://huff.to/1KxxoZF

  19. Syria - 2013 *aljazeera.com

  20. *https://www.wired.co.uk/article/over-50-internet-shutdowns-2016*https://www.wired.co.uk/article/over-50-internet-shutdowns-2016

  21. *http://wapo.st/1UVKamr

  22. The top-secret PRISM program *https://www.washingtonpost.com/wp-srv/special/politics/prism-collection-documents/

  23. Network Neutrality • Can the Internet Service Provider (ISP) selectively slow down traffic? 2017 2015 *http://nyti.ms/2CkTbRR *http://nyti.ms/2kZUnDA

  24. Who should pay for the Internet connection? Netflix VS ISPs The Netflix-Comcast conflict *https://freedom-to-tinker.com/2015/03/25/why-your-netflix-traffic-is-slow-and-why-the-open-internet-order-wont-necessarily-make-it-faster/

  25. Who should pay for the Internet connection? Netflix VS ISPs Netflixdownloadratedroppedto0.5 Mbps in New York because of thecongestiononCogentlinks *https://arstechnica.com/information-technology/2014/10/study-comcast-and-verizon-connections-to-cogent-dropped-below-0-5mbps/

  26. Who should pay for the Internet connection? Netflix VS ISPs Netflixstarts paying. *https://arstechnica.com/information-technology/2014/10/study-comcast-and-verizon-connections-to-cogent-dropped-below-0-5mbps/

  27. A Fragile place

  28. *https://dyn.com/blog/widespread-impact-caused-by-level-3-bgp-route-leak/*https://dyn.com/blog/widespread-impact-caused-by-level-3-bgp-route-leak/

  29. We have a little problemhere… • A little outage – for more than 90 mins • Affected millions of users from the US and world-wide • Cause: BGP routeleaking • A misconfigured routerdirectedInternet traffic from its intended path to somewhere else.

  30. *https://dyn.com/blog/widespread-impact-caused-by-level-3-bgp-route-leak/*https://dyn.com/blog/widespread-impact-caused-by-level-3-bgp-route-leak/

  31. August 2017 *https://www.theregister.co.uk/2017/08/27/google_routing_blunder_sent_japans_internet_dark/

  32. Human factor • People also often mistakenly destroy their own infrastructure

  33. Human factor • People also often mistakenly destroy their own infrastructure „Human factors are responsible for 50% to 80% of network outages.” Jupiter Networks, What’sBehind Network Downtime?, 2008

  34. Data networks work better during week-ends…

  35. Computer NetworksCourse

  36. Goals of this course • Understand how and why Internet works… • Main topics • Addressing • How to address devices, services and protocols? • Layering • How to handle complexity? • Routing • How to go from A to B? • Reliability • How to communicate reliably over an unreliable mediums? • Resource sharing • How to divide scare resources among competing parties?

  37. Skills – that are also essential in Matrix TrinityfromMatrixReloaded running a port scan, using the toolnmap…

  38. Sources • Slides: • http://lakis.web.elte.hu • Books      

  39. Teaching Style • I am a network researcher • Things make sense to me that may not make sense to you • If youdonotunderstandsomething, donot be shytostop me and ask • Seriously, ask questions!!! • Standing up here in silence is very awkward • I will stand here until you answer my questions • Help me learn your names • Say your name before each question

  40. Course = Lecture + Practice • Practice • Lecturer: Dhulfiqar A Alwahab, PhD Student • Requirementswereannouncedatthefirstclassyesterday • Lecture • After a successfullypassedpractical part… • Finalexamat end of thesemester • oneoccasion per weekintheexamperiod • writtenexam – tests + essay

  41. Cheating • Do not do it • Seriously, don’t make me say it again • Cheating is an automatic zero • Will be referred to the university for discipline and possible expulsion

  42. Final Grades • At the end of the semester, all of your grades will sum to 100 points • Final grades are based on a simple scale: • 5 - >85, • 4 - 70-85, • 3 - 60-70, • 2 - 50-60, • 1 - 0-50

  43. After typeingwww.google.cominto a browser, and pressing enter… What happens? Can you list any technologies, principles, protocols and applications used…

  44. Overview What is a network made of?

  45. Three main components

  46. Data sending and receiving end-points Linux server Computer in a car Pacemaker Smartphone Windows PC Smart TV iPad Smart Fridge Drone

  47. Data forwardingswitches and routersData forwarding towards a destination switch/router

  48. Routersdifferent sizes, features and applications Home router data center router Internet core router ~20 cm ~50cm >200 cm 0,5 kg ~ 5 kg ~700 kg 1 Gbps 1,8-6,5 Tbps 12,8 Tbps (upto 922 Tbps)

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