Glava9-Protokoli Za Rutiranje

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Телекомуникациски склопови и уреди

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  • .- ,

    9-1

    9

    , 7. ,

    BGP

    , RIP OSPF

    .

    .

    9.1 Gateway

    Exterior Gateway Protocol (EGP)

    . TCP/IP

    . Border Gateway Protocol (BGP),

    ( ) . ,

    : BGP-4. BGP,

    BGP-4.

    , BGP .

    peer . BGP

    peer ,

  • .- ,

    9-2

    . , BGP

    border gateway ( ) border router ( ).

    9.1 . , R1

    1 R2

    BGP, R2 2.

    1

    2

    .

    . . ..BGP

    (Border Gateway Protocol)

    R1 R2

    9.1 BGP

    9.1.1 BGP

    BGP distance-vector ,

    link-state . :

    BGP gateway , .

    peer , BGP

    .

    BGP ,

    .

    distance-vector , BGP -hop .

    . distance-vector , BGP

    . , BGP

  • .- ,

    9-3

    .

    BGP TCP . , TCP

    .

    BGP . , BGP

    . ,

    ,

    (deltas).

    , .. BGP CIDR .

    9.1.2 BGP

    BGP peer :

    peer . peer TCP

    . -

    . ,

    hop ,

    .

    peer .

    , BGP

    , 9.1.

    9.1 BGP-4

    1 OPEN

    2 UPDATE

    3 NOTIFICATION

    4 KEEPALIVE

  • .- ,

    9-4

    BGP

    BGP

    . 9.2 .

    ( )

    0 16 24 31

    9.2 BGP

    16- (MARKER)

    . 2- (LENGTH)

    .

    19 ( ),

    4096 . , 1- (TYPE)

    9.1.

    BGP OPEN

    BGP peer TCP ,

    OPEN

    .

    , OPEN hold timer

    . 9.3 .

    (VERSION)

    ( 4). (AUTONOMOUS

    SYSTEM NUM) .

    (HOLD TIME)

  • .- ,

    9-5

    .

    .

    ()

    BGP

    (Hold Time)

    0 8 16 31

    9.3 BGP OPEN

    ; ,

    (

    ). BGP (IDENTIFIER) 32-

    . .

    PARM.LEN , Optional Parameters

    .

    BGP UPDATE

    BGP peer TCP , OPEN

    . Peer UPDATE

    . 9.4 UPDATE

    .

  • .- ,

    9-6

    ( )

    ( )

    0 16 31

    ( )

    ( )

    ( )

    9.4 BGP UPDATE

    9.4, UPDATE :

    ,

    .

    (WITHDRAWN LEN) 2-

    Withdrawn Destinations .

    , WITHDRAWN LEN .

    (PATH LEN) Path Attributes

    .

    .

    IP /

    Withdrawn Destinations Destination Networks IP

    . , BGP

    IP .

    32- , BGP

    . 9.5 .

    BGP bit- . ,

    . integer

    1 .

    -

    . , IP

    8 ,

  • .- ,

    9-7

    9 16, IP 17 24

    IP 25 32.

    (

    ). default- .

    IP ( 1 4 , IP mask)

    IP mask

    0 8 31

    9.5 BGP IP

    BGP

    BGP distance-vector

    hop. Path

    Attributes .

    : hop ,

    ,

    .

    UPDATE . : ,

    loop-.

    . ,

    loop. ,

    . ,

    . ,

    .

    ,

    gateway BGP gateway . ,

  • .- ,

    9-8

    .

    BGP KEEPALIVE

    BGP peer KEEPALIVE

    . KEEPALIVE

    . , 19

    ( BGP ).

    BGP keepalive . ,

    BGP TCP , TCP

    . , TCP

    . ,

    keepalive, TCP . ,

    keepalive .

    BGP hold timer .

    BGP . Hold timer-

    keepalive .

    KEEPALIVE hold timer-.

    ,

    Gateway

    . ,

    ,

    ( ). 9.6 .

    , R2 BGP

    . hop,

    1 R1, 3 4 R3,

    2 R2.

  • .- ,

    9-9

    R1

    R3

    R2

    R4

    Net 5

    Net 4

    Net 3

    Net 2Net 1

    Koristi BGP

    Do peer na drug avtonomen sistem

    Slika 9.6 Primer za avtonomen sistem

    BGP NOTIFICATION

    BGP NOTIFICATION

    . , BGP

    , notification TCP .

    9.7 .

    (Data)

    0 31168

    9.7 BGP NOTIFICATION

    8- (ERR CODE)

    , 9.2.

    - (sub-code) .

  • .- ,

    9-10

    9.2 ERR CODE BGP NOTIFICATION

    ERR CODE

    1

    2 OPEN

    3 UPDATE

    4 Hold Timer

    5

    6 ( )

    9.2 RIP (Routing Information Protocol)

    , ,

    (interior) . 9.8

    .

    R2

    R3 R4

    R1

    Net 1

    Net 5Net 4

    Net 3

    Net 2

    Slika 9.8 Primer na mala mre`a sostavena od 5 Ethernet i 4 ruteri

    .

    host- .

    .

  • .- ,

    9-11

    :

    . ,

    9.9.

    R2

    R3 R4

    R1

    Net 1

    Net 5Net 4

    Net 3

    Net 2

    Slika 9.9 Dodavawe na R5 voveduva alternativen pat pome|u mre`ite 2 i 3

    R5

    ,

    .

    ,

    .

    ,

    .

    ,

    .

    , Interior Gateway Protocol (IGP)

    . ,

    core SPREAD IGP.

    BGP IGP. 9.10

    , IGP

    .

  • .- ,

    9-12

    .

    . ....

    BGP

    R1 R2

    IGP2IGP1

    IGP1 IGP2

    9.10 BGP ( ) IGP ( )

    9.10, IGP1

    AS1, IGP2 AS2.

    : ,

    .

    , BGP ,

    IGP A.

    IGP RIP , Routing Information

    Protocol. distance-vector

    . .

    , RIP

    ,

    . RIP , host-

    .

    RIP ,

    30 .

    . IP

    integer . RIP hop count metric

    j. RIP, 1 hop

    ; 2 hop- , .

    RIP

    . , : ,

    RIP

  • .- ,

    9-13

    (

    ).

    ?

    RIP

    RIP. ,

    .

    RIP . 180

    .

    RIP

    . , loop-, RIP

    loop-. , RIP

    (RIP 16

    , ). , distance-vector

    RIP

    ,

    .

    .

    R1

    R1

    R3

    R2 R3

    R2 1

    2

    a)

    b) 9.11 : ) , 1; )

    1 , R2 (loop)

    . 9.11a

    1 R1, R2 R3.

    9.11, R1 1,

    1,

  • .- ,

    9-14

    . R2 R1, 2 ,

    R3 R2 3.

    R1 1 . R1

    16 ().

    , R1 . , R2

    R1 . , R1 R2

    distance-vector : R2

    1 , 3 hop-

    1 (2 R2 a 1 1 R1 R2), R1

    R2 hop. a, R1 R2

    1,

    . RIP

    . , R1

    . R1 1

    3, R2 4.

    , R1 R2 ,

    5.

    RIP.

    9.11

    split horizon update.

    ,

    . , split horizon R2

    1 R1, R1

    1, R2.

    loop . ,

    , .

    loop- .

    hold down.

  • .- ,

    9-15

    . , hold down 60 .

    .

    loop-, () hold down

    .

    poison reverse. ,

    ,

    . ,

    .

    , .

    .

    9.2.1 RIP1

    RIP :

    .

    distance .

    9.12 1 ,

    RIP1.

    0 8 16 31 COMMAND (1-5) VERSION (1) MUST BE ZERO

    FAMILY OF NET 1 MUST BE ZERO

    IP ADDRESS OF NET 1

    MUST BE ZERO

    MUST BE ZERO

    DISTANCE TO NET 1

    FAMILY OF NET 2 MUST BE ZERO

    IP ADDRESS OF NET 2

    MUST BE ZERO

    MUST BE ZERO

    DISTANCE TO NET 2

    . . . 9.12 RIP 1

  • .- ,

    9-16

    host-

    request . response .

    Version .

    RIP1

    . 9.12, RIP

    14 . , IP 4; RIP

    . FAMILY OF

    NET .

    RIP 0.0.0.0 default- .

    RIP , DISTANCE TO NET i,

    .

    hop-.

    9.2.2 RIP2

    RIP2 RIP1 ,

    .