What is the function of the 'bgp neighbor' command?

The 'bgp neighbor' command is used to configure a BGP peer relationship, which is essential for establishing BGP communication between routers. When you use this command, you specify the IP address of the neighboring router and define parameters such as the remote AS (Autonomous System) number, which allows the local router to recognize that it needs to exchange routing information with that neighbor. Establishing a BGP peer relationship is crucial for the BGP protocol to function, as it enables the routers to share information about the routes to different IP networks and ensures that they can make informed routing decisions based on that information. This command is foundational in setting up BGP and facilitating inter-domain routing.