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At the heart of EIGRP is the Diffusing Update Algorithm (DUAL), the decision process for
all route computations. DUAL uses distance information to select
efficient, loop-free paths and selects the best route for insertion
into the routing table, as well as a feasible successor. This
feasible successor is used if the primary route becomes unavailable,
thus avoiding a complete recalculation of the algorithm in the event
of a link failure, and hence lowering convergence time. EIGRP also
introduced a Reliable Transport Protocol to ensure guaranteed, ordered delivery of routing
updates, rather than relying on broadcasts. |
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