mạng máy tính nâng cao nguyễn đức thái chương 1 introduction sinhvienzone com

Zo ne C om Chapter Introduction nh Vi en A note on the use of these ppt slides: Si 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 Computer Networking: A Top Down Approach , 4th edition Jim Kurose, Keith Ross Addison-Wesley, July 2007 Thanks and enjoy! JFK/KWR All material copyright 1996-2007 J.F Kurose and K.W Ross, All Rights Reserved SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-1 Chapter 1: Introduction om C  what’s a protocol?  network edge; hosts, access nh Vi en terminology  more depth, detail later in course  approach:  use Internet as example  what’s the Internet? ne  get “feel” and Overview: Zo Our goal:  Si     SinhVienZone.com net, physical media network core: packet/circuit switching, Internet structure performance: loss, delay, throughput security protocol layers, service models history Introduction https://fb.com/sinhvienzonevn 1-2 .C 1.1 What is the Internet? 1.2 Network edge om Chapter 1: roadmap Zo 1.3 Network core ne  end systems, access networks, links nh Vi en  circuit switching, packet switching, network structure Si 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 SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-3 What’s the Internet: “nuts and bolts” view computing devices: hosts = end systems  running network apps  communication links Global ISP nh Vi en Zo ne wireless laptop cellular handheld C server Mobile network om  millions of connected PC fiber, copper, radio, satellite  transmission rate = bandwidth  routers: forward packets (chunks of data)  Regional ISP Institutional network Si access points wired links Home network router SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-4 Zo Si nh Vi en IP picture frame http://www.ceiva.com/ Web-enabled toaster + weather forecaster ne C om “Cool” internet appliances World’s smallest web server http://www-ccs.cs.umass.edu/~shri/iPic.html SinhVienZone.com Internet phones Introduction https://fb.com/sinhvienzonevn 1-5 What’s the Internet: “nuts and bolts” view networks”   loosely hierarchical public Internet versus private intranet om Global ISP ne Internet: “network of Zo e.g., TCP, IP, HTTP, Skype, Ethernet C receiving of msgs   Mobile network protocols control sending, nh Vi en  Home network Regional ISP Institutional network Si  Internet standards  RFC: Request for comments  IETF: Internet Engineering Task Force SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-6 What’s the Internet: a service view om  communication Si nh Vi en Zo ne 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 C infrastructure enables SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-7 What’s a protocol? Si om C ne nh Vi en … specific msgs sent … specific actions taken when msgs received, or other events SinhVienZone.com network protocols:  machines rather than humans  all communication activity in Internet governed by protocols Zo human protocols:  “what’s the time?”  “I have a question”  introductions protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt Introduction https://fb.com/sinhvienzonevn 1-8 What’s a protocol? C om a human protocol and a computer network protocol: Zo ne Hi Got the time? Si 2:00 nh Vi en Hi TCP connection request TCP connection response Get http://www.awl.com/kurose-ross time Q: Other human protocols? SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-9 .C 1.1 What is the Internet? 1.2 Network edge om Chapter 1: roadmap Zo 1.3 Network core ne  end systems, access networks, links nh Vi en  circuit switching, packet switching, network structure Si 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 SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-10 Network Security om  The field of network security is about: how bad guys can attack computer networks  how we can defend networks against attacks  how to design architectures that are immune to attacks Zo ne C  nh Vi en  Internet not originally designed with (much) security in mind  original vision: “a group of mutually trusting Si users attached to a transparent network”   Internet protocol designers playing “catch-up”  Security considerations in all layers! SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-66 om Bad guys can put malware into hosts via Internet  Malware can get in host from a virus, worm, or ne C trojan horse  Spyware malware can record keystrokes, web nh Vi en Zo sites visited, upload info to collection site  Infected host can be enrolled in a botnet, used Si for spam and DDoS attacks  Malware is often self-replicating: from an infected host, seeks entry into other hosts SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-67 ne C  Worm:  infection by passively receiving object that gets itself executed  self- replicating: propagates to other hosts, users Zo  Trojan horse  Hidden part of some otherwise useful software  Today often on a Web page (Active-X, plugin) om Bad guys can put malware into hosts via Internet Sapphire Worm: aggregate scans/sec in first minutes of outbreak (CAIDA, UWisc data) Si nh Vi en  Virus  infection by receiving object (e.g., e-mail attachment), actively executing  self-replicating: propagate itself to other hosts, users SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-68 om Bad guys can attack servers and network infrastructure  Denial of service (DoS): attackers make resources select target nh Vi en break into hosts Zo ne C (server, bandwidth) unavailable to legitimate traffic by overwhelming resource with bogus traffic Si around the network (see botnet) send packets toward target from compromised hosts SinhVienZone.com target Introduction https://fb.com/sinhvienzonevn 1-69 The bad guys can sniff packets om Packet sniffing: broadcast media (shared Ethernet, wireless)  promiscuous network interface reads/records all packets (e.g., including passwords!) passing by Zo ne C  nh Vi en A Si src:B dest:A  C payload B Wireshark software used for end-of-chapter labs is a (free) packet-sniffer SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-70 .C spoofing: send packet with false source address C payload nh Vi en src:B dest:A Zo ne A B Si  IP om The bad guys can use false source addresses SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-71 om The bad guys can record and playback nh Vi en Zo ne C  record-and-playback: sniff sensitive info (e.g., password), and use later  password holder is that user from system point of view Si A C src:B dest:A user: B; password: foo B SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-72 Network Security om  more throughout this course C  chapter 8: focus on security Si nh Vi en Zo not so obvious uses ne  crypographic techniques: obvious uses and SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-73 .C 1.1 What is the Internet? 1.2 Network edge om Chapter 1: roadmap Zo 1.3 Network core ne  end systems, access networks, links nh Vi en  circuit switching, packet switching, network structure Si 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 SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-74 Internet History C  ARPAnet public demonstration NCP (Network Control Protocol) first host-host protocol first e-mail program ARPAnet has 15 nodes    Si nh Vi en Zo theory shows effectiveness of packetswitching  1964: Baran - packetswitching in military nets  1967: ARPAnet conceived by Advanced Research Projects Agency  1969: first ARPAnet node operational  1972: ne  1961: Kleinrock - queueing om 1961-1972: Early packet-switching principles SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-75 Internet History    C Zo nh Vi en  Cerf and Kahn’s internetworking principles:  minimalism, autonomy - no internal changes required to interconnect networks  best effort service model  stateless routers  decentralized control define today’s Internet architecture Si  network in Hawaii 1974: Cerf and Kahn architecture for interconnecting networks 1976: Ethernet at Xerox PARC ate70’s: proprietary architectures: DECnet, SNA, XNA late 70’s: switching fixed length packets (ATM precursor) 1979: ARPAnet has 200 nodes ne  1970: ALOHAnet satellite om 1972-1980: Internetworking, new and proprietary nets SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-76 Internet History om 1980-1990: new protocols, a proliferation of networks C Si  Csnet, BITnet, NSFnet, Minitel  100,000 hosts connected to confederation of networks Zo  nh Vi en  TCP/IP 1982: smtp e-mail protocol defined 1983: DNS defined for name-to-IPaddress translation 1985: ftp protocol defined 1988: TCP congestion control  new national networks: ne  1983: deployment of  SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-77 Internet History  more killer apps: instant messaging, P2P file sharing  network security to forefront  est 50 million host, 100 million+ users  backbone links running at Gbps Si nh Vi en Zo ne decommissioned  1991: NSF lifts restrictions on commercial use of NSFnet (decommissioned, 1995)  early 1990s: Web  hypertext [Bush 1945, Nelson 1960’s]  HTML, HTTP: Berners-Lee  1994: Mosaic, later Netscape  late 1990’s: commercialization of the Web Late 1990’s – 2000’s: C  Early 1990’s: ARPAnet om 1990, 2000’s: commercialization, the Web, new apps SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-78 Si nh Vi en Zo ne C 2007:  ~500 million hosts  Voice, Video over IP  P2P applications: BitTorrent (file sharing) Skype (VoIP), PPLive (video)  more applications: YouTube, gaming  wireless, mobility om Internet History SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-79 .C You now have:  context, overview, “feel” of networking  more depth, detail to follow! Si nh Vi en Zo ne Covered a “ton” of material!  Internet overview  what’s a protocol?  network edge, core, access network  packet-switching versus circuit-switching  Internet structure  performance: loss, delay, throughput  layering, service models  security  history om Introduction: Summary SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1-80 ... protocol layers, service models history Introduction https://fb.com/sinhvienzonevn 1- 2 .C 1. 1 What is the Internet? 1. 2 Network edge om Chapter 1: roadmap Zo 1. 3 Network core ne  end systems, access... Other human protocols? SinhVienZone.com Introduction https://fb.com/sinhvienzonevn 1- 9 .C 1. 1 What is the Internet? 1. 2 Network edge om Chapter 1: roadmap Zo 1. 3 Network core ne  end systems, access...  geosynchronous versus low altitude Introduction https://fb.com/sinhvienzonevn 1- 26 .C 1. 1 What is the Internet? 1. 2 Network edge om Chapter 1: roadmap Zo 1. 3 Network core ne  end systems, access