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DUAL

Diffusing Update Algorithm

6

, Bellman - ford.

Merion Academy


(Diffusing Update Algorithm -DUAL) - , . , , . , .

1993 Bellman-Ford Dijkstra . , , " " , DUAL.

DUAL , . 8 9. DUAL, A, , . , , downstream neighbor, , downstream neighbor.

8 D A:

  1. A D:
    1. H 3.
    2. C 4.
  1. A B, B A :
    1. A - B D.
    2. B A D ( ), , D ( C) A.
    3. B split horizon D A, .
  2. A :
    1. H .
    2. , 3.
  3. A , , - downstream neighbors:
    1. C 3.

A , C D , 3.

A C .

, A C A.

  1. 3 ( C) = 3 ( A), , , C . C downstream neighbors.

Downstream neighbors DUAL . , [A, H] . DUAL , A . A . , . [A, H] , D:

  1. A (Downstream neighbors).
  2. , A D ( ).
  3. A , , - D.
  4. C:
    1. C E ( A, ).
    2. E , A D. , C .
    3. C 3 A.
  5. B:
    1. - .
    2. B , D , .
    3. B , .
    4. B A, ( ).
  6. A :
    1. C - , 4.
    2. A C .
    3. D . , (downstream neighbor).

9 (D) H E. .

(downstream neighbor).

D A:

  1. A D:
    1. H 4.
    2. C 3.
  2. A B:
    1. B D.
    2. C A 4.
    3. B A, C.
    4. B split horizon D A, A .
  3. A :
    1. C .
    2. , 3.
  4. A , , - downstream neighbors:
    1. H 2.
    2. 2 ( H) = 3 ( A), . , H .
    3. H (downstream neighbors).

[A, C] , A:

  1. A .
  2. H.
  3. A H .
    1. , .
    2. , . 3.
  4. A , , D 3 4.

, , , , . , DUAL ( , EIGRP), , . , , , .

10 DUAL.

, route gets worse ( ), :

  • , ,
  • , ,
 DUAL
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