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Computer Networks and Communications [Δίκτυα Υπολογιστών και Επικοινωνίες] Lectures 8&9: Internet Protocols in Detail – TCP/IP Univ. of the Aegean Financial and Management Engineering Dpt. Petros KAVASSALIS. What you will learn in this course.
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Computer Networks and Communications[Δίκτυα Υπολογιστών και Επικοινωνίες]Lectures 8&9: Internet Protocols in Detail – TCP/IPUniv. of the Aegean Financial and Management Engineering Dpt Petros KAVASSALIS
What you will learn in this course • A set of fundamental concepts for understanding Data Networks and the Internet • What is the Internet? • Internet architecture and layers • Internet applications and services • New concepts in the evolution of the Internet • The Internet goes Wireless… • Familiarization with the structure and organization of Digital Networks • Business and Social Networks • Electronic Markets and Online Feedback Mechanisms
Who am I? • PhDinEconomicsandManagement (Univ. ParisDauphine & Ecolepolytechnique) • Research experience • Ecolepolytechnique, Paris • MIT CenterofTechnologyPolicyandIndustrialDevelopment, MIT CTPID (MIT Internet TelecommunicationsConvergenceConsortium) • Current positions • Univ. of the Aegean (FME): Assoc. Professor • RACTI: Director of ATLANTIS Group
Communication tools • e-mail: pkavassalis [at] atlantis-group.gr • Course web site: see fme website
Course Textbook[http://books.google.gr/books?id=Pd-z64SJRBAC&dq=tanenbaum+networks&printsec=frontcover&source=bn&hl=el&ei=ml-dSfH9L4S2jAeJ5L3ZBQ&sa=X&oi=book_result&resnum=4&ct=result]
Supplementary Texts & References William Stallings, Computer Networking with Internet Protocols, Prentice Hall, 2004 James F. Kurose and Keith W. Ross, Computer Networking: A Top-Down Approach, Addison-Wesley, 2008
Students evaluation • Class Participation (20%) + • Assignments (20%) + • Final Exam (60%)
Reminder: Overview of the Internet The structure of the Internet is roughly hierarchical
Internet Transport Layer • Common layer shared by all applications • Provides reliable delivery of data • In same order as sent • Commonly uses TCP • Example: Web browsing • Uses also UDP (for real-time traffic)
application transport network data link physical application transport network data link physical logical end-end transport Internet Transport Layer key role • Providelogical communication between app processes running on different hosts • Transport protocols run in end systems • Send side: breaks app messages into segments, passes to network layer • Receive side: reassembles segments into messages, passes to app layer • Two mail transport protocol available to apps • Internet: TCP and UDP
application transport network data link physical application transport network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical logical end-end transport Internet Transport Layer Protocols • Reliable, in-order delivery (TCP) • Congestion control • Flow control • Connection setup • Unreliable, unordered delivery: UDP • No-frills extension of “best-effort” IP • Services not available: • Delay guarantees • Bandwidth guarantees
Internet Network Layer • Exchange of data between an end system and attached network • Concerned with issues like : • Destination address provision • Invoking specific services like priority • Access to & routing data across a network link between two attached systems • Allows layers above to ignore link specifics
Internet Network Layer key role • Transport segment from sending to receiving host • On sending side encapsulates segments into datagrams • On receiving side, delivers segments to transport layer • Network layer protocols in every host, router • Host: Creates datagrams / headers • Router examines header fields in all IP datagrams passing through it
application transport network data link physical application transport network data link physical Internet Network Layer in a nutshell 1. Send data 2. Receive data • No call setup at network layer • Routers: no state about end-to-end connections • no network-level concept of “connection” • Packets forwarded using destination host address • packets between same source-dest pair may take different paths
network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical network data link physical application transport network data link physical application transport network data link physical Internet Network Layer functionality • Forwarding • Move packets from router’s input to appropriate router output • Routing • Determine route taken by packets from source to destination
Addressing requirements • Two levels of addressing required • Each host on a subnet needs a unique global network address • IP address • Each application on a (multi-tasking) host needs a unique address within the host • Port