DUAL, the
Diffusing
Update
ALgorithm, is the
algorithm used by
Cisco's
EIGRP routing protocol to ensure that a given route is recalculated globally whenever it might cause a routing loop. It was developed by J.J. Garcia-Luna-Aceves at
SRI International. According to Cisco, the full name of the algorithm is DUAL
finite-state machine (DUAL FSM). EIGRP is responsible for the routing within an autonomous system and DUAL responds to changes in the routing topology and dynamically adjusts the routing tables of the router automatically.