Diffusing update algorithm

From Wikipedia, the free encyclopedia

DUAL stands for Diffusing Update ALgorithm and is the algorithm used by EIGRP to ensure that a given route is recalculated globally when it might cause a routing loop.

EIGRP uses a feasibility condition to ensure that only loop-free routes are ever selected. Unfortunately, the feasibility condition may, under some conditions, cause all routes to a given destination to be rejected.

When no feasible route to a destination is available, the DUAL algorithm[1] invokes a Diffusing Computation [2] to ensure that all traces of the problematic route are eliminated from the network. At which point the normal Bellman-Ford algorithm is used to recover a new route.

[edit] References

  1. ^ The DUAL Algorithm
  2. ^ Termination Detection for Diffusing Computations - Dijkstra, Scholten - 1980
Languages