Budapest University of Technology and Economics, Faculty of Electrical Engineering and Informatics

    címtáras azonosítással

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    Communication Networks I.

    A tantárgy neve magyarul / Name of the subject in Hungarian: Kommunikációs hálózatok 1

    Last updated: 2021. október 6.

    Budapest University of Technology and Economics
    Faculty of Electrical Engineering and Informatics
    Course ID Semester Assessment Credit Tantárgyfélév
    VIHIAB01 3 2/0/1/f 4  
    3. Course coordinator and department Dr. Simon Vilmos,
    4. Instructors

    Dr. Bokor László egyetemi docens, HIT

    Dr. Pekár Adrián egyetemi adjunktus, HIT

    5. Required knowledge
    6. Pre-requisites
    (TárgyEredmény( "BMEVIMIAA01" , "aláírás" , _ ) = -1
    VAGY TárgyEredmény( "BMEVIMIAA02" , "aláírás" , _ ) = -1
    VAGY TárgyEredmény( "BMEVIMIA111" , "aláírás" , _ ) = -1 )

    ÉS NEM ( TárgyEredmény( "BMEVIHIA215", "jegy" , _ ) >= 2
    VAGY TárgyEredmény("BMEVIHIA215", "FELVETEL", AktualisFelev()) > 0)

    ÉS (Training.Code=("5N-A8") VAGY Training.Code=("5NAA8"))

    A fenti forma a Neptun sajátja, ezen technikai okokból nem változtattunk.

    A kötelező előtanulmányi rend az adott szak honlapján és képzési programjában található.

    VIMIAA01 Digitális technika, VIHIAB00 Kódolástechnika (párhuzamos felvételre), VIHIAA00 Számítógép-architektúrák.
    8. Synopsis

    The main goal of this course is to introduce the basic paradigms, architectures and protocols of communication networks to students. The course follows a top-down approach. The students will get familiar with the basic paradigms, architectures and protocols of communication networks through the transport, network, data link, and physical layers. Topics, among others, include the main application layer protocols like DNS and HTTP, congestion control solutions, UDP and TCP protocols, routing schemes, IPv4 and IPv6, medium access, and the essentials of physical layer techniques. Laboratory experiments help students to deepen their understanding of the essential characteristics of the most important building blocks of IP-based communication networks.


    Students who successfully accomplish the course will understand

    • essentials of IP-based communication networks from the application to the physical layers,
    • routing techniques and protocols,
    • IPv4 and IPv6 network layer solutions,
    • congestion control paradigms,
    • UDP and TCP mechanisms and TCP session management,
    the operation of main network layer protocols like DNS, SMTP, FTP, and HTTP,
    9. Method of instruction


    Introduction to networked systems and networking techniques. History of the Internet and its general architecture. Overview of applications and services (e.g. web, file transmission, e-mail, P2P, multi-media streaming). Requirements of communication, QoS/QoE basics, packet loss and delay.

    2. Hét

    Protocol architectures and the reference models: ISO/OSI, TCP/IP, circuit switching, packet switching, addressing.

    3. hét
    Network applications 1 - Infrastructure services: DNS (functionalities, requirements, zone, servers, operation, messages). Dynamic Host Configuration Protocol. Text and file transmission: Telnet, File Transfer Protocol.

    4. hét
    Network applications 2 - Mailing systems: Simple Mail Transfer Protocol, Post Office Protocol, Internet Message Access Protocol. Web solutions: Hypertext Transfer Protocol, persistent and non-persistent operation, message formats, commands, headers.


    5. hét
    Transport layer: general characteristics, goals, sockets, socket types, User Datagram Protocol (ports, headers), Congestion control: goals of congestion control, congestion control vs. flow control, general solutions and mechanisms, stop-and-wait operation.


    6. hét
    Transmission Control Protocol (main characteristics and operation, segment format, session establishment).

    7. hét
    Transmission Control Protocol (retransmission cases, fast retransmit, timeout interval calculation, AIMD, Slow Start).

    8. hét
    Network layer and Internet Protocol (IP): IP functionalities, characteristics, addressing (classes, public/private addresses), Classless Inter-domain Routing, IPv4, IPv4 header structure

    9. hét
    Routing: the function itself, bridging vs. routing, routing tables, distance vector and link-state based protocols. Hierarchical routing, autonomous systems, multicast routing basics.


    IP routing (RIP, OSPF, BGP), Address Resolution Protocol, IP fragmentation, IP signaling and management (ICMP and IGMP).

    11. hét
    IPv6: motivations - problems and issues with IPv4, IPv6 header structure, address autoconfiguration, IPv6 routing, IPv6 migration, IPv4 and IPv6 in practice, addressing, network aggregation, IPv6 addresses canonical format, EIU-64 algorithm.

    Data link layer and LANs: principles behind data link layer services, error detection, correction, sharing a broadcast channel, multiple access, link layer addressing, Ethernet.

    Data link layer and LANs: Wi-Fi and other instantiation and implementation of link layer technologies, brief introduction to physical layer (major functions and services, encoding, transmission, reception and decoding).

    14. hét
    Outlook: internet of things, vehicular communication

    Laboratory #1: TCP/IP protocol stack (1x4 hours)
    Wireshark (basic usage, capture filter, display filter; Ethernet, IP, ICMP, TCP, UDP headers). ARP: Request, Reply, Probe and Announcement. DHCP: Release, Ack, Discover, Offer, Request, Ack. ping and traceroute. TCP session creation and termination. TCP session count. TCP congestion control. TCP options.

    Laboratory #2: Network applications (1x4 hours)
    DNS: „A", „PTR" and „AAAA" records. SMTP: manual e-mail sending (HELO, MAIL FROM, RCPT TO, DATA (From:, To:, Subject:, Date: and payload), QUIT), envelope sender/recipient header fields. POP3: USER, PASS, STAT, LIST, RETR, DELE, RSET, QUIT commands. FTP: client, active and passive mode, BIN vs ASCII file transfer, FTP PASV mode with telnet. HTTP: GET, 1.0 vs. 1.1. SSH and SCP: key generation, login, file transfer.

    Laboratory #3: IPv6 operation and IPv6 migration techniques (1x4 hours)
    Stateless address autoconfiguration (SLAAC) (neighbor solicitation, router solicitation, router advertisement messages, link-local and global unicast addresses, EUI-64). DNS64: common DNS64 server setup. Linux DNS64 server configuration. Common NAT64 Gateway to reach IPv4 only servers: first with HTTP, then with FTP passive and active mode. Further application tests (SMTP, POP3). Traceroute experiments. NAT64 gateway usage on local Linux (TAYGA + IPTABLES already configured).

    10. Assessment


    Laboratories: mandatory to have all 3 laboratories successfully completed, only 1 laboratory can be repeated.


    Midterm test: successful test with at least 50%. No exam.

    Grade calculation: 66% test points, 34% laboratory points.

    11. Recaps


    1 laboratory can be repeated (independently of the reason of the failure /failed entry test or failed laboratory tasks/).

    Midterm test can be repeated once during the repetition week.

    12. Consultations

    13. References, textbooks and resources Course website: 
    •    James F. Kurose - Keith W. Ross: Számítógép-hálózatok működése, Panem, 2008 (ISBN 978-963-5454-98-3).
    •    Andrew S. Tannenbaum: Számítógéphálózatok, Panem, 2004 (ISBN 978-963-5453-84-1).
    •    Lencse Gábor: Számítógép hálózatok, Universitas-Győr Nonprofit Kft, Győr, 2008 (ISBN 978-903-9819-15-3).
    •    Lencse Gábor, Répás Sándor, Arató András: IPv6 és bevezetését támogató technológiák, HunNet-Média Kft, Budapest, 2015, (ISBN: 978-963-12-3272-1), DOI: 10.18660/ipv6-b1.2015.9.1,
    14. Required learning hours and assignment

    Contact hours


    Preparation for laboratories


    Preparation for presentations


    Preparation for midterm test


    Preparation for laboratory entry tests




    15. Syllabus prepared by

    Dr. Simon Vilmos      Egyetemi docens      HIT 
    Dr. Szabó Csaba Attila      Egyetemi tanár     HIT 
    Dr. Lencse Gábor    Tud. főmunkatárs    HIT

    Dr. László Bokor, egyetemi docens, HIT