Which event occurs in the open confirm state?

• A. The router received agreement on the parameters for establishing a session.
• B. An open message was sent with the parameters for the BGP session.
• C. The router found a route to the neighbor and has completed the three-way handshake.
• D. Peering is established and routing begins.

Answer: (A)

OpenConfirm is reached after the BGP OPEN messages have been exchanged and the parameters are being checked and agreed upon by both sides. The key event in this state is that the router has received the neighbor’s OPEN and validated the session parameters (version, AS numbers, hold time, etc.). Once that agreement is established, the session exchanges a KEEPALIVE to move toward Established, where actual routing updates begin.

So the event described—receiving agreement on the parameters for establishing a session—is what defines OpenConfirm. The other events occur earlier (sending your OPEN) or later (peering and routing begin once Established), or relate to the underlying TCP connection rather than the BGP parameter negotiation.