DUAL
Diffusing Update Algorithm
(Diffusing Update Algorithm -DUAL) - , . , , . , .
1993 Bellman-Ford Dijkstra . , , " " , DUAL.
DUAL , . 8 9. DUAL, A, , . , , downstream neighbor, , downstream neighbor.
8 D A:
- A D:
- H 3.
- C 4.


- A B, B A :
- A - B D.
- B A D ( ), , D ( C) A.
- B split horizon D A, .
- A :
- H .
- , 3.
- A , , - downstream neighbors:
- C 3.
A , C D , 3.
A C .
, A C A.
- 3 ( C) = 3 ( A), , , C . C downstream neighbors.
Downstream neighbors DUAL . , [A, H] . DUAL , A . A . , . [A, H] , D:
- A (Downstream neighbors).
- , A D ( ).
- A , , - D.
- C:
- C E ( A, ).
- E , A D. , C .
- C 3 A.
- B:
- - .
- B , D , .
- B , .
- B A, ( ).
- A :
- C - , 4.
- A C .
- D . , (downstream neighbor).
9 (D) H E. .
(downstream neighbor).
D A:
- A D:
- H 4.
- C 3.
- A B:
- B D.
- C A 4.
- B A, C.
- B split horizon D A, A .
- A :
- C .
- , 3.
- A , , - downstream neighbors:
- H 2.
- 2 ( H) = 3 ( A), . , H .
- H (downstream neighbors).
[A, C] , A:
- A .
- H.
- A H .
- , .
- , . 3.
- A , , D 3 4.
, , , , . , DUAL ( , EIGRP), , . , , , .
10 DUAL.
, route gets worse ( ), :
- , ,
- , ,
