— BGP: neighbor peer remote-as asn

Creates a new neighbor whose remote-as is asn. peer can be an IPv4 address or an IPv6 address.

          router bgp 1
           neighbor 10.0.0.1 remote-as 2
     

In this case my router, in AS-1, is trying to peer with AS-2 at 10.0.0.1.

This command must be the first command used when configuring a neighbor. If the remote-as is not specified, bgpd will complain like this:

          can't find neighbor 10.0.0.1