Bài giảng Mạng máy tính nâng cao - Chapter 1: Introduction cung cấp cho người học các kiến thức: Network edge, network core, delay, loss and throughput in packet-switched networks, protocol layers, service models,... Mời các bạn cùng tham khảo.
Chapter Introduction 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 Computer Networking: A Top Down Approach , 5th edition Jim Kurose, Keith Ross Addison-Wesley, April 2009 Thanks and enjoy! JFK/KWR All material copyright 1996-2009 J.F Kurose and K.W Ross, All Rights Reserved CuuDuongThanCong.com Introduction https://fb.com/tailieudientucntt 1-1 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 Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-2 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 Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-3 What’s the Internet: “nuts and bolts” view PC Hàng triệu thiết bị tính tốn nối mạng: server wireless laptop cellular handheld access points wired links router hosts = end systems chạy ứng dụng mạng communication links fiber, copper, radio, satellite transmission rate = bandwidth routers: Chuyển packets (gói tin) Mobile network Global ISP Home network Regional ISP Institutional network Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-4 “Cool” internet appliances Web-enabled toaster + weather forecaster IP picture frame http://www.ceiva.com/ World’s smallest web server http://www-ccs.cs.umass.edu/~shri/iPic.html Internet phones Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-5 What’s the Internet: “nuts and bolts” view protocols (giao thức) điều Mobile network khiển việc gửi/nhận msg Global ISP e.g., TCP, IP, HTTP, Skype, Ethernet Internet: “mạng mạng” loosely hierarchical public Internet versus private intranet Home network Regional ISP Institutional network Các tiêu chuẩn Internet RFC: Request for comments IETF: Internet Engineering Task Force Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-6 What’s the Internet: a service view Hạ tầng truyền thông (communication infrastructure) cho phép ứng dụng phân bố: Web, VoIP, email, games, e-commerce, file sharing Các ứng dụng sử dụng dịch vụ truyền thông (communication services) Truyền liệu bảo đảm từ máy nguồn đến máy đích Truyền liệu thường (ko bảo đảm) Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-7 What’s a protocol? human protocols: “Mấy rồi?” “Cho hỏi” giới thiệu … gửi thông điệp định … hành động định thực nhận thông điệp, có kiện khác network protocols: Máy tính, ko phải người Tất hoạt động truyền thông Internet phải tuân thủ protocols protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-8 What’s a protocol? a human protocol and a computer network protocol: Xin chào TCP connection request Xin chào Cho hỏi rồi? TCP connection response Get http://www.awl.com/kurose-ross 2:00 Thời gian Q: Other human protocols? Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-9 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 Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-10 Network Security An ninh mạng nhằm nghiên cứu về: Cách thức kẻ xấu công vào MMT Cách thức bảo vệ MMT khỏi đợt công Cách thức thiết kế mạng đề kháng với đợt công Ban đầu, Internet không thiết kế với ý định an ninh original vision: “a group of mutually trusting users attacked to a transparent network” ☺ An ninh mạng cần xem xét tất tầng! Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-68 Bad guys can put malware into hosts via Internet Malware xâm nhập máy tính từ virus, worm, trojan horse Spyware malware ghi nhận bàn phím, viếng thăm website, tải thơng tin lên site Các máy tính bị lây nhiễm kết nạp vào botnet, sử dụng cho cơng spam DDoS Malware thường có khả tự nhân (selfreplicating): từ máy tính bị lây nhiễm, tìm kiếm máy tính khác để lây nhiễm tiếp Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-69 Bad guys can put malware into hosts via Internet Trojan horse Phần ẩn vài phần mềm có ích Hiện tại: dạng Active-X, plugin từ trang Web Virus Gây lây nhiễm nhờ việc người kích hoạt ứng dụng Tự nhân bản: tự lây lan đến file khác máy Worm: Gây lây nhiễm việc công vào lổ hổng bảo mật, ko cần người kích hoạt Tự nhân bản: tự lây lan đến máy tính khác Sapphire Worm: aggregate scans/sec in first minutes of outbreak (CAIDA, UWisc data) Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-70 Bad guys can attack servers and network infrastructure Tấn công từ chối dịch vụ (Denial of service -DoS): kẻ công sử dụng số luợng lớn truy cập hợp lệ làm cạn kiệt tài nguyên mạng (Server, băng thơng) Chọn đích cơng Xâm nhập máy tính khác từ mạng Huy động máy tính bị xâm nhập, đồng loạt gửi gói tin đến máy bị công target Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-71 The bad guys can sniff packets Packet sniffing: broadcast media (shared Ethernet, wireless) promiscuous network interface reads/records all packets (e.g., including passwords!) passing by C A src:B dest:A payload B Wireshark software used for end-of-chapter labs is a (free) packet-sniffer Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-72 The bad guys can use false source addresses IP spoofing: send packet with false source address C A src:B dest:A payload B Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-73 The bad guys can record and playback record-and-playback: sniff sensitive info (e.g., password), and use later password holder is that user from system point of view C A src:B dest:A user: B; password: foo B Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-74 Network Security more throughout this course chapter 8: focus on security crypographic techniques: obvious uses and not so obvious uses Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-75 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 Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-76 Internet History 1961-1972: Early packet-switching principles 1961: Kleinrock - queueing theory shows effectiveness of packet-switching 1964: Baran - packetswitching in military nets 1967: ARPAnet conceived by Advanced Research Projects Agency 1969: first ARPAnet node operational 1972: ARPAnet public demonstration NCP (Network Control Protocol) first host-host protocol first e-mail program ARPAnet has 15 nodes Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-77 Internet History 1972-1980: Internetworking, new and proprietary nets 1970: ALOHAnet satellite 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 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 Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-78 Internet History 1980-1990: new protocols, a proliferation of networks 1983: deployment of TCP/IP 1982: smtp e-mail protocol defined 1983: DNS defined for name-to-IP-address translation 1985: ftp protocol defined 1988: TCP congestion control new national networks: Csnet, BITnet, NSFnet, Minitel 100,000 hosts connected to confederation of networks Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-79 Internet History 1990, 2000’s: commercialization, the Web, new apps Early 1990’s: ARPAnet 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 Late 1990’s – 2000’s: more killer apps: instant messaging, P2P file sharing network security to forefront est 50 million host, 100 million+ users backbone links running at Gbps of the Web Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-80 Internet History 2007: ~500 million hosts Voice, Video over IP P2P applications: BitTorrent (file sharing) Skype (VoIP), PPLive (video) more applications: YouTube, gaming wireless, mobility Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-81 Introduction: Summary 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 You now have: context, overview, “feel” of networking more depth, detail to follow! Introduction CuuDuongThanCong.com https://fb.com/tailieudientucntt 1-82 ... https://fb.com/tailieudientucntt 1- 13 Dial-up Modem Văn phịng trung tâm telephone network Máy tính gia đình home dial-up modem Internet ISP modem (e.g., AOL) Sử dụng hạ tầng mạng điện thoại có Máy tính gia đình... Tier-2 ISP local ISP Tier-2 ISP local ISP Introduction https://fb.com/tailieudientucntt 1- 44 Chapter 1: roadmap 1. 1 What is the Internet? 1. 2 Network edge end systems, access networks, links 1. 3... https://fb.com/tailieudientucntt 1- 2 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,