BGP working states

BGP, or the Border Gateway Protocol, is a routing protocol used to exchange routing information between different networks on the internet. In order to establish a successful BGP session, the BGP protocol goes through several working states.

Here are the BGP working states:

Idle State: This is the initial state of BGP, where the protocol waits for a connection to be established with a neighbor router.

Connect State: In this state, the BGP protocol attempts to establish a TCP connection with the neighbor router.

Active State: If the Connect State fails, BGP enters the Active State and continues trying to establish a connection with the neighbor router.

Open Sent State: In this state, the BGP protocol sends an Open message to the neighbor router, which includes the BGP version number, the Autonomous System Number (ASN), and other capabilities.

Open Confirm State: After receiving the Open message from the neighbor router, BGP enters the Open Confirm State and waits for a confirmation message from the neighbor router.

Established State: Once the confirmation message is received, BGP enters the Established State, where it begins exchanging routing information with the neighbor router.

In the Established State, BGP routers exchange information about the prefixes they know about and the paths to those prefixes. This allows routers to determine the best path for traffic to take between networks.

Overall, understanding the BGP working states is important for network engineers and administrators to ensure that BGP sessions are established and maintained properly.