1. Introduction 1-1 Networking Admin  1 to 4 lectures a week for 11 weeks for a total of 23 lectures  Interleaves with Functional Programming  First prac this week (THU 17): then every second teaching week (5 pracs in total)

2. Practicals with a difference  Two weeks to ‘execute them’  Self assessment  They will be as last year, so you will be able to have the solutions ahead of handing in, if you like  responsibility  Well, PERSONAL RESPONSIBILITY should be the keyword of your relation with this course  It worked reasonably well last year and the year before Introduction 1-2

3. The course is entirely based on a book (a very good one!)  First 5 chapters (about 500 pages)  Of course, some material will be left out: altogether about 260 pages  Still, 10 to 20 pages to read per lecture (depending on difficulty)  Book must be read BEFORE practicals, though might be understood for real just after ending prac Introduction 1-3

4. The book again…  Important: references in the book. Get used to that and use them (within reason)  Another important resource, of course: the internet (for example wikipedia and from there to ‘core’ documents, up to RFCs; www.networksorcery.com is a very useful resource for protocols) Introduction 1-4

5. So why having lectures?  Actually not too sure: tradition? Lack of inventiveness? Because life has to be hard, as parents / teachers kept telling you? ;-)  Lectures to get your interest going, or to clarify general / difficult concepts  To ease the difficulty of self learning (which remains the best way to learn, however)  As interactive as possible, please (like, don’t fall asleep…) Introduction 1-5

6. Introduction 1-6 The book (and a lot of material!) Computer Networking: A Top Down Approach, 4 th edition. Jim Kurose, Keith Ross Addison-Wesley, July 2007. A note on the use of these ppt slides: We’re making these slides freely available to all (faculty, students, readers). They’re in PowerPoint form so you can add, modify, and delete slides (including this one) and slide content to suit your needs. They obviously represent a lot of work on our part. In return for use, we only ask the following:  If you use these slides (e.g., in a class) in substantially unaltered form, that you mention their source (after all, we’d like people to use our book!)  If you post any slides in substantially unaltered form on a www site, that you note that they are adapted from (or perhaps identical to) our slides, and note our copyright of this material. Thanks and enjoy! JFK/KWR All material copyright 1996-2007 J.F Kurose and K.W. Ross, All Rights Reserved

7. Introduction 1-7 Chapter 1: Introduction Our goal:  get “feel” and terminology  more depth, detail later in course  approach:  use Internet as example Overview:  what’s the Internet?  what’s a protocol?  network edge; hosts, access net, physical media  network core: packet/circuit switching, Internet structure  performance: loss, delay, throughput  security  protocol layers, service models  history

8. Introduction 1-8 Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  circuit switching, packet switching, network structure 1.4 Delay, loss and throughput in packet-switched networks 1.5 Protocol layers, service models 1.6 Networks under attack: security 1.7 History

9. Introduction 1-9 What’s the Internet: “nuts and bolts” view  millions of connected computing devices: hosts = end systems  running network apps Home network Institutional network Mobile network Global ISP Regional ISP router PC server wireless laptop cellular handheld wired links access points  communication links  fiber, copper, radio, satellite  transmission rate = bandwidth  routers: forward packets (chunks of data)

10. Introduction 1-10 “Cool” internet appliances World’s smallest web server http://www-ccs.cs.umass.edu/~shri/iPic.html IP picture frame http://www.ceiva.com/ Web-enabled toaster + weather forecaster Internet phones

11. Introduction 1-11 What’s the Internet: “nuts and bolts” view  protocols control sending, receiving of msgs  e.g., TCP, IP, HTTP, Skype, Ethernet  Internet: “network of networks”  loosely hierarchical  public Internet versus private intranet  Internet standards  RFC: Request for comments  IETF: Internet Engineering Task Force Home network Institutional network Mobile network Global ISP Regional ISP

12. Introduction 1-12 What’s the Internet: a service view  communication infrastructure enables distributed applications:  Web, VoIP, email, games, e-commerce, file sharing  communication services provided to apps:  reliable data delivery from source to destination  “best effort” (unreliable) data delivery

13. Introduction 1-13 What’s a protocol? human protocols:  “what’s the time?”  “I have a question”  introductions … specific msgs sent … specific actions taken when msgs received, or other events network protocols:  machines rather than humans  all communication activity in Internet governed by protocols protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt

14. Introduction 1-14 What’s a protocol? a human protocol and a computer network protocol: Q: Other human protocols? Hi Got the time? 2:00 TCP connection request TCP connection response Get http://www.awl.com/kurose-ross time

15. Introduction 1-15 Chapter 1: roadmap 1.1 What is the Internet? 1.2 Network edge  end systems, access networks, links 1.3 Network core  circuit switching, packet switching, network structure 1.4 Delay, loss and throughput in packet-switched networks 1.5 Protocol layers, service models 1.6 Networks under attack: security 1.7 History

16. Introduction 1-16 A closer look at network structure:  network edge: applications and hosts  access networks, physical media: wired, wireless communication links  network core:  interconnected routers  network of networks

17. Introduction 1-17 The network edge:  end systems (hosts):  run application programs  e.g. Web, email  at “edge of network” client/server peer-peer  client/server model  client host requests, receives service from always-on server  e.g. Web browser/server; email client/server  peer-peer model:  minimal (or no) use of dedicated servers  e.g. Skype, BitTorrent