������������ ������������ ��������������� ��������������������� 2006/2007 ������ �� �������� ���������������� G. Bianchi, G. Neglia ����������� �������� �������� �� �� ����������� ����������������� �������� ��������� 1. transmission technologies • physical carriers, modulation, etc 2. data link protocols • reliable transfer of bits from point to point 3. Packet switching • Historical perspective, then technologies, routing, protocols, finally IP 4. Packet forwarding • Glue IP routing with layer 2, ARP,... 5. Transport protocols, application protocols • In a rush!! (just a bit of TCP, HTTP, …) G. Bianchi, G. Neglia 1
�������� ������� ������� ��� ������� ���� ������ ������ �������� � (almost) Top-Down � Applications are indeed important � What you see is what you learn first � Start focusing on internet application programming � Notion of sockets (no Java programming this year) � Transport layer as application developement platform � Web as driving application � Limited details on other apps G. Bianchi, G. Neglia Course objectives objectives & limits & limits Course � ������� �!" � ���������������������������������������������������������� � ������������� ��� ��������� ���� ���� �������� �� ���� ��� � ��������� ���������� �� ������� �� ������ ��������� ������������������� � ������� ���� �� ���� ����� ���� �������� ����� � #�$��!" � ������������� �� !"���#������$����������%�������������� ���� ������� �� ����&������� ��������������������� ' ����������� ����������������� � (������������������������� �������������������� �� ������ �������������� G. Bianchi, G. Neglia 2
Teaching Material Material Teaching � Book and notes � Nicola Blefari Melazzi, dispense, versione 4.2 (in italian), 2003 • Available online • In progress (310 pages at the moment) � James F. Kurose, Keith W. Ross • Italian version: Internet e reti di calcolatori, McGraw-Hill, approx 40 � • top-down approach � Additional reference books & material � Stevens (vol. 1), 1994 • to dip into technical issues • a VALUABLE book (though a bit too old) � RFCs: the real stuff… � Sites: � www.ietf.org � Internet standardization � www.w3.org � Web standardization G. Bianchi, G. Neglia Course contents contents Course � PART A: Applications � Internet architecture, internet standardization, switching basics � Application addressing, Internet applications development (JAVA-based) � World wide web; HTTPv1.0 details � Domain Name System � PART B: Transport � User Datagram Protocol � Introduction to TCP, pipelining, performance issues � TCP algorithms: (a) window flow control; (b) TCP error control; (c) TCP congestion control. � PART C: Network � IP addressing � IP packet forwarding (ARP), IP address assignment (RARP, DHCP) � Advanced IP addressing: subnetting & supernetting (CIDR) � IP and ICMP details � IP routing (BGP, OSPF) � extra Time? Never happened… � P2P applications (BitTorrent?) G. Bianchi, G. Neglia 3
Internet traffic traffic growth growth Internet (USA - - recent recent measurements measurements) ) (USA G. Bianchi, G. Neglia Traffic share share - - projections projections Traffic IP TRAFFIC MIX - P2P SCENARIO 100% SHARE OF TOTAL TRAFFIC 90% 80% 70% WEB PAGES 60% RICH MEDIA 50% P2P 40% S2S 30% 20% 10% 0% 2001 2002 2003 2004 2005 2006 2007 2008 source: Cohen Communications Group G. Bianchi, G. Neglia 4
Why “ “All All” over IP? ” over IP? Why Packet 15 Times 1200 Greater Than Circuit PetaBytes per Month 1000 800 Telephony 600 Internet 400 200 0 97 98 99 00 01 02 Year End Source: M. Decina, 2000 G. Bianchi, G. Neglia Voice over IP Voice over IP – – deployment deployment (source: F. Carlini, november 2003) (source: F. Carlini, november 2003) � ITA: Fastweb � All-IP Voice service � ITA: Telecom Italia � 100% (!!) Telephone traffic, MI-RM-NA backbone is IP • Did you know? � International traffic � 12% of whole international traffic is IP � Ongoing direction: � User VoIP awareness (e.g. Fastweb) G. Bianchi, G. Neglia 5
What was was the Internet the Internet What ( for ) ( ago ) for the mass the mass- -media, a few media, a few years years ago � Internet synonimous of WWW ( W orld W ide W eb) sites & pages: • millions of documents • Spreaded worldwide • mostly written in HTML language ( HyperText Markup Language ) • mostly accessible via the HTTP protocol ( HyperText Transfer Protocol ) G. Bianchi, G. Neglia What was was the Internet the Internet What ( ( for in the 80s ) ) for the the scientist scientist in the 80s � Internet synonimous of FTP ( F ile T ransfer P rotocol) and e-mail: • Scientists were the only ones having a presence on the Internet (unix logins) » contacts via email, talk program • Research documents archived in FTP sites » accessible via FTP, gopher • Scientific (and cultural) forums: Usenet news G. Bianchi, G. Neglia 6
What is is the internet the internet What ( for ) ( today ) for the mass media, the mass media, today � Huge marketplace for e-business � B2B and B2C portals with full-fledged transaction capabilities � Virtual communities � Chat & messaging � Peer to peer applications � Communication network � IP Telephony / Multimedia commun. G. Bianchi, G. Neglia What will will be be the Internet the Internet What (in 2010?) (in 2010?) � High speed unique integrated telecommunication network and business services platform • High Speed = Broadband • Unique = integrated services network • Services = from communication to distributed systems • ??? � Worldwide operating system? � Content delivery network? p2p? ??? � Internet Appliances, the real revolution? ??? G. Bianchi, G. Neglia 7
What is What is the Internet the Internet (For For networking networking engineers engineers: : We We!) !) ( 1. A worldwide computer network � Connecting end-systems (host, servers) � Each uniquely identified by a numeric address (IP address) 2. the world wide group of networks combined with TCP/IP � TCP/IP synonimous of the entire suite of networking protocols. • The name comes from the two most important: » TCP = Transmission Control Protocol » IP = Internet Protocol 3. A packet switching network G. Bianchi, G. Neglia What Internet Internet is is: a network of : a network of What heterogeneous networks heterogeneous networks Internet and host Private Nets %�&�� ����� Token router router Power- &��'&��� Ring line central !�������� ���' Ethernet Power line Host = 1 interface Router = 2+ interfaces G. Bianchi, G. Neglia 8
TCP/IP characteristics characteristics TCP/IP � TCP/IP provides services necessary to create the Internet, by: • interconnecting computers & • interconnecting networks � Independence from underlying network topology, physical network hardware, Operating Systems, etc � Universal connectivity throughout the network � Standardize High Level protocols G. Bianchi, G. Neglia What What Internet Internet attempts attempts to to be be ( (but but only only loosely loosely is is): ): a hierarchical hierarchical network... network... a G. Bianchi, G. Neglia 9
Architecture Hierarchy Hierarchy - - USA USA Architecture � Local ISPs � Regional ISPs � National & International Backbone Providers (NBPs) � InternetMCI, Sprintlink, PSINet, UUNet, Technologies, AGIS, … � interconnected via big switching centers called Network Access Points (NAPs), or Metropolitan Area Exchanges (MAEs) � or private peering points (Point of Presence, PoP) G. Bianchi, G. Neglia A NAP: just A NAP: just another another router… router…? ? Pacific Bell Bell Pacific S. Francisco S. Francisco NAP NAP G. Bianchi, G. Neglia 10
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