# EIGRP DUAL FSM (Finite State Machine)

**URL:** https://forum.networklessons.com/t/eigrp-dual-fsm-finite-state-machine/1865
**Category:** Lessons Discussion
**Created:** [June 29, 2017, 9:46am UTC](https://forum.networklessons.com/t/eigrp-dual-fsm-finite-state-machine/1865 "2017-06-29T09:46:37Z")
**Posts on this page:** 1
**Showing post:** 6

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### Author: ![hugodiaz1988](https://cdn-forum.networklessons.com/letter_avatar_proxy/v4/letter/h/a88e57/32.png) [@hugodiaz1988](https://forum.networklessons.com/u/hugodiaz1988)
#### Post date: [February 18, 2020, 9:14pm UTC](https://forum.networklessons.com/t/eigrp-dual-fsm-finite-state-machine/1865/6 "2020-02-18T21:14:30Z")

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I am having a very hard time understanding this concept with the demonstrated diagram.  
My main problem is not seeing a defined path (to my lack of understanding) as to the Input Events and their corresponding state.  
I understand the overall goal of DUAL and how it functions (to some degree), but when presented the diagram I don’t know what it means to have those 4 different “types?” of ACTIVE states, and what is the structure of the Input Events.

Are the numbers a representation of the process of each one? or is it just one of the Input events that changes the state from Passive to Active (and vise versa).

How are the Query and Reply flags structured?

I guess I am over thinking this a lot, and the diagram might just be making it more complicated than it is, but I figured I could submit the question.

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