1 / 117

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

aldan
Download Presentation

Computer/ Telecommunication Networks

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  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)

More Related