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  • 2005/03/11(C) Herbert Haas

    The Internet Protocol (IP)

    The Blood of the Internet

  • "Information Superhighway is really an acronym for 'Interactive Network For Organizing, Retrieving, Manipulating,

    Accessing And Transferring Information On National Systems, Unleashing Practically

    Every Rebellious Human Intelligence, Gratifying Hackers, Wiseacres,

    And Yahoos'."

    Keven Kwaku

  • 3(C) Herbert Haas 2005/03/11

    The Internet Protocol (IP)

    Introduction IP Addressing

    IP Header IP Address Format

    Address Classes Class A - E

    Subnetting, VLSM IP Fragmentation

  • 4(C) Herbert Haas 2005/03/11

    Need of an Inter-Net Protocol (1)

    Different Data-Link Layer Different frames Different protocol handling

    Different Physical Layer Different hardware Different signals

    No interconnection possible !!!

    Host 1

    Host 2 Host 3

    Host 1

    Host 2

    Host 3

    Host 1

    Host 3 Host 2

  • 5(C) Herbert Haas 2005/03/11

    Need of an Inter-Net Protocol (2)

    Network 1

    Network 3

    Network 2

    Common internetworking layer One packet type

    Gateways terminate layer 1 and 2 Layer 3 addresses identify

    Not only Host But also Network

    Gateway

    Gateway

    1.1

    1.2 1.3

    2.1

    2.2

    3.4

    3.1

    3.3 3.2

    2.3

    2.4

  • 6(C) Herbert Haas 2005/03/11

    IP Introduction (1)

    Packet switching technology Packet switch = router = "gateway" (IETF terminology) End system is called IP host Layer 3 address (Structured)

    Datagram Service Connectionless Best effort delivery

  • 7(C) Herbert Haas 2005/03/11

    Packet Switching Principle

    T1

    T2

    T3

    TA T2

    T3

    T1

    T4 T4

    T4 T4T1 TB

    User A2

    User B5

    Address Information

    • Each switch must analyze address information

    • "Store and Forward"

  • 2005/03/11 8

    A

    D C

    B

    PS2 PS3 PS4

    IP packet forwarding is based on routing tables only (Connectionless PS, Best-Effort Service, Datagram Service)

    A B

    ... Packet payload

    A B A B

    A B time t0

    time t2 time t4

    time t6

    time t1 forwarding decision

    of PS2 time t3

    forwarding decision of PS3

    time t5 forwarding decision

    of PS4

    A B ... Source Address / Destination Address

    B PS3 C PS3 D PS3

    to next hop

    B PS4 C PS5 D PS6

    to next hop

    B local C PS5 D PS3

    to next hop

    Routing Table of PS 4

  • 2005/03/11 9

    14 CR A B

    A

    E C

    B

    PS2 PS3 PS4

    CR ... Call Request

    X.25/FR/ATM packet forwarding is based on X25/FR/ATM switching tables; but call-setup uses routing tables (Connection Oriented PS, Virtual Call Service)

    A :14

    from to

    from to

    from to B PS3 C PS3 E PS3

    to next hop

    Switching Table of PS 4

    unique addresses

    local connection identifier

    packet type

    Routing Table of PS 2

    Virtual Call Setup 1

  • 2005/03/11 10

    23 CR A B

    A

    E C

    B1

    2 3 4

    5 6

    CR ... Call Request

    14

    Virtual Call Setup 2

    A :14 3:23

    from to

    2 :23

    from to from to

    B PS4 C PS5 E PS6

    to next hop

  • 2005/03/11 11

    A

    E C

    B1

    2 3 4

    5 6

    CR ... Call Request

    14

    07 CR A B

    23

    Virtual Call Setup 3

    3:07

    from to

    A :14 3:23

    from to

    2 :23 4:07

    from to

    B local C PS5 E PS3

    to next hop

  • 2005/03/11 12

    44 CR A B

    A

    E C

    B1

    2 3 4

    5 6

    CR ... Call Request

    14

    23

    07

    Virtual connection A - B: 14-23-07-44

    Virtual Call Setup 4

    A :14 3:23

    from to

    3:07 B:44

    from to

    2 :23 4:07

    from to

  • 2005/03/11 13 CA ... Call Accepted

    A B CA 44

    A

    E C

    B1

    2 3 4

    5 6

    14

    23

    07

    Virtual connection A - B: 14-23-07-44

    44

    Virtual Call Setup 5

    A :14 3:23

    to from

    3:07 B:44

    to from

    2 :23 4:07

    to from

  • 2005/03/11 14 CA ... Call Accepted

    A

    E C

    B1

    2 3 4

    5 6

    14

    23

    07

    Virtual connection A - B: 14-23-07-44

    44 A B CA 14

    Virtual Call Setup 6

    A :14 3:23

    to from

    3:07 B:44

    to from

    2 :23 4:07

    to from

  • 2005/03/11 15

    A

    E C

    B1

    2 3 4

    5 6

    14

    23

    07

    Virtual connection A - B: 14-23-07-44

    44 D 14

    D ... Data Packet … payload

    Data Transfer 1

    A :14 3:23

    from to

    3:07 B:44

    from to

    2 :23 4:07

    from to

  • 2005/03/11 16

    A

    E C

    B1

    2 3 4

    5 6

    14

    23

    07

    Virtual connection A - B: 14-23-07-44

    44

    D 23

    D ... Data Packet … payload

    Data Transfer 2

    A :14 3:23

    from to

    3:07 B:44

    from to

    2 :23 4:07

    from to

  • 2005/03/11 17

    A

    E C

    B1

    2 3 4

    5 6

    14

    23

    07

    Virtual connection A - B: 14-23-07-44

    44

    D 07

    D ... Data Packet … payload

    Data Transfer 3

    A :14 3:23

    from to

    3:07 B:44

    from to

    2 :23 4:07

    from to

  • 2005/03/11 18

    A

    E C

    B1

    2 3 4

    5 6

    14

    23

    07

    Virtual connection A - B: 14-23-07-44

    44 D 44

    D ... Data Packet … payload

    Data Transfer 4

    A :14 3:23

    from to

    3:07 B:44

    from to

    2 :23 4:07

    from to

  • 2005/03/11 19

    IP Datagram Service

    User A.2

    User B.5

    R1 R2

    R4

    R3

    R5

    Destination Next Hop A local B R2 C R2

    ..... .....

    A2 B5

    A2 B5

    A2 B5

    Destination Next Hop A R1 B R4 C R3

    ..... .....

    A 2

    B 5

    Destination Next Hop A R2 B R5 C R2

    ..... .....

    A2 B5

    Destination Next Hop A R4 B local C R4

    ..... .....IP address (structured address Net-ID:Host-ID)

    IP Host IP Router

    IP Routing Table of R1

    Destination Based Routing

  • 20(C) Herbert Haas 2005/03/11

    IP Introduction (2)

    Shared responsibility Both network and hosts must take care for delivery (!) Routers deliver datagrams to remote hosts based on IP address Hosts responsible for end-to-end control

    End-to-end control relies on TCP Layer 4

  • 21(C) Herbert Haas 2005/03/11

    IP Introduction (3)

    Physical

    Application

    Presentation

    Session

    Transport

    Network

    Link IP over

    Internet Protocol (IP)

    TCP (Transmission Control Protocol)

    ATM RFC 1483

    IEEE 802.2 RFC 1042

    X.25 RFC 1356

    Frame Relay RFC 1490

    PPP RFC 1661

    UDP (User Datagram

    Protocol)

    HTTP FTP DNSTelnetSMTP TFTPDHCP etc.

    Routing Protocols

    RIP, OSPF, BGP, EGP

    OSI 7 Layer Model

    TCP/IP Protocol Suite

    ARPRARP

    ICMP

    (US-ASCII and MIME)

    Inverse ARP

  • 2005/03/11 22

    IP Host A IP Host B

    3 33 3 IP

    M M

    3 3

    Layer 3 Protocol = IP Layer 3 Routing Protocols = RIP, OSPF, EIGRP, BGP

    IP and OSI Network Layer 3

    Router 1 Router 2IP IP

  • 23(C) Herbert Haas 2005/03/11

    IP Introduction (4)

    IP over anything: Overlay Technique IP can be easily integrated upon layer 2 technologies Open development quickly adapts to new transport and switching methods

    End-to-end principle Only hosts must be intelligent (TCP) Routers remain simple

  • 24(C) Herbert Haas 2005/03/11

    IP Introduction (5)

    TCP cares for reliability Connection oriented Error recovery Flow control Sequencing

    IP is the router's language No idea about applications Best effort delivery

  • 2005/03/11 25

    4 4

    Layer 4 Protocol = TCP (Connection-Oriented)

    M M

    TCP/UDP and OSI Transport Layer 4

    IP Host A IP Host B

    Router 1 Router 2

    Layer 4 Protocol = UDP (Connectionless)

    TCP/UDP Connection (Transport-Pipe)

  • 26(C) Herbert Haas 2005/03/11

    IP Introduction (6)

    Request for Comments (RFCs) De fact