BGP Finite-State Machine (BGP FSM)

[a1111]

Hello, 

I've created a flowchart for the BGP FSM. Do you think I have to add or correct anything? The main goal is to learn the most important details.

I've used the ENCOR OCG, and these sites:

https://www.catchpoint.com/bgp-monitoring/bgp-states

https://www.inetdaemon.com/tutorials/internet/ip/routing/bgp/operation/finite_state_model.shtml

https://notes.networklessons.com/bgp-finite-state-machine-fsm

https://www.ciscopress.com/articles/article.asp?p=2756480&seqNum=4

This last one is the most detailed. I assume it is most useful when troubleshooting a complex issue, rather than as a learning aid:

https://nwktimes.blogspot.com/2017/07/border-gateway-protocol-finite-state.html

Thanks

[Ramblin Tech]

Check your FSM against that in BGP-4 RFC 4271 Section 8. As long as you end up in the same state with the same event occurrence, then you should be good. It appears that you have chosen to transition between states via flow-chart style decisions for conciseness/clarity, rather than strictly keying on the RFC enumerated events, but it is the end result that really matters, as is stated in the RFC itself:

   The data structures and FSM described in this document are conceptual
   and do not have to be implemented precisely as described here, as
   long as the implementations support the described functionality and
   they exhibit the same externally visible behavior.