The diffusing update calculation (DUAL) is the calculation utilized by EIGRP steering convention to ensure that a given course is recalculated around the world at whatever point it could cause a directing circle. It is ensures circle free and reinforcement ways all through the steering space. EIGRP store all suitable reinforcement courses utilizing diffusing update calculation and afterward adjust the course when required. There are a few terms utilizes in diffusing update calculation, which are:
- Possible Distance (FD)
- Possible Successor (FS)
- Detailed Distance (RD) or Advertised Distance (AD)
- Possible Condition or Feasibility Condition (FC)
Double is the calculation utilized by EIGRP for union. Union is vital to an organization for trying not to defeat circles. Steering circles are exceptionally harming to organize execution. EIGRP utilizes a hold-down clock and split skyline to forestall directing circles.
The essential way that EIGRP forestalls directing circles is with the DUAL calculation. It gives circle opportunity at each occurrence all through a course computation. The DUAL permits all switches in a geography change to synchronize simultaneously. Switches not impacted by the geography changes are not piece of recalculation. Double EIGRP is the method of quicker assembly than other distance vector directing conventions.
The DUAL Finite State Machine (FSM) is the choice interaction for all course calculations. Limited State Machine (FSM) is a work process model containing a set number of states, changes between those states, and FSM Operation.
The diffusing update calculation FSM tracks all courses use EIGRP measurements to choose productive, circle free ways and recognize the courses with the smallest expense way to be embedded into the directing table.
EIGRP stays away from recalculation at whatever point conceivable in light of the fact that recalculation is processor-concentrated. EIGRP stay away from recalculation by keeping a rundown of reinforcement courses that DUAL has recently found for circle free. In the event that the essential course in the steering table not working, the best reinforcement course is straight away added to the directing table.
Double Finite State Machine (FSM)
The DUAL Finite State Machine (FSM) is EIGRP course computation motor. This FSM contains rationale to compute and look at courses in an EIGRP organization. It is a theoretical machine, not a mechanical gadget with moving parts. It characterizes the different condition of conceivable outcomes expresses that something can go through, what procedures cause those states, and what procedures result from those states. FSMs are excluded from the extent of CCNA. However, the idea is utilized to inspect a portion of the result from EIGRP’s FSM utilizing the “troubleshoot eigrp fsm” order.