Which one do I trust ? :-) RFC: Idle state:

      Initially, the BGP peer FSM is in the Idle state.  Hereafter, the
      BGP peer FSM will be shortened to BGP FSM.

      In this state, BGP FSM refuses all incoming BGP connections for
      this peer.  No resources are allocated to the peer.  In response
      to a ManualStart event (Event 1) or an AutomaticStart event (Event
      3), the local system:

        - initializes all BGP resources for the peer connection,

        - sets ConnectRetryCounter to zero,

        - starts the ConnectRetryTimer with the initial value,

        - initiates a TCP connection to the other BGP peer,

        - listens for a connection that may be initiated by the remote
          BGP peer, and

        - changes its state to Connect.

      The ManualStop event (Event 2) and AutomaticStop (Event 8) event
      are ignored in the Idle state.

Rekhter, et al.             Standards Track                    [Page 53]

RFC 4271                         BGP-4                      January 2006

      In response to a ManualStart_with_PassiveTcpEstablishment event
      (Event 4) or AutomaticStart_with_PassiveTcpEstablishment event
      (Event 5), the local system:

        - initializes all BGP resources,

        - sets the ConnectRetryCounter to zero,

        - starts the ConnectRetryTimer with the initial value,

        - listens for a connection that may be initiated by the remote
          peer, and

        **- changes its state to Active.**

Wikipedia https://en.wikipedia.org/wiki/Border_Gateway_Protocol : enter image description here

  • I don't understand, the quoted section of the RFC says "changes its state to Connect" which is what the diagram on Wikipedia shows. There doesn't seem to be any conflict here.
    – MAP
    Aug 3, 2016 at 5:20
  • Wikipedia does not say it can go to Active but the standard says it can
    – MiniMe
    Aug 3, 2016 at 9:45
  • I just reread the section of the standard you quoted and it says nothing about going to Active. I'm not rereading the whole RFC to try and find what you are referring to. But, if you are trying to make the claim that the RFC has a transition from Idle to Active, then quote the part that says that.
    – MAP
    Aug 4, 2016 at 1:12
  • The quoted section of the RFC says it goes from Idle to Connect, not from Idle to Active. The RFC and Wikipedia are in complete agreement. What's your problem?
    – MAP
    Aug 4, 2016 at 1:17
  • I invite you to scroll down in my post to see "what my problem is" It is the last line in that quote. It contains the magical word Active which I think turns blind some of us
    – MiniMe
    Aug 4, 2016 at 10:05

2 Answers 2


The RFC is the standard, I would go with that

  • I believe that the Wikipedia diagram does not include all the situations. On the other side the RFC mentions one particluar situation when the router goes into Active from Connect and the Wikipedia picture captures that ...
    – MiniMe
    Aug 2, 2016 at 21:09
  • Wait,. now you're talking about going from Connect to Active. Both the RFC and the Wikipedia diagram show that. But that's not what your question was about. Could you get your story straight?
    – MAP
    Aug 4, 2016 at 1:14
  • It is from Idle all the way, my initial story is straight. Focus on the question and on the discrepancies in the sources quoted not on my afterwards errors
    – MiniMe
    Aug 4, 2016 at 10:07

Hy MiniMe, Good question.

In general, being the RFC the network reference, I for sure trust what RFC says.

Anyway RFC states in page 54 in case of responce to a passive manual/automatic start event, the router start to listen for any incoming request from its peers and put its self in active state skipping the Connect state.

This COULD be due to the fact that the the router has to perform a PASSIVE connection with the peer, so it waits for an incoming request from the peer skipping the connect state (in which it tries to establish the tcp connection).

  • that is exactly the page that I quoted. and yes that was my conclusion too ...see may comment on Aug 2 at 21:09
    – MiniMe
    Aug 6, 2016 at 1:50

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