BGP is like any app that uses on TCP which means that through TCP client relationship creates the t

BGP is like any app that uses on TCP which means that through TCP client relationship creates the three-way-handshake so by sending a SYN Fktt towards Port 179, if there is a router at the other end is configured to accept the BGP he replies with a SYN / ACK
If two neighbors trying to establish neighborly relations at the same time there is a tool by RFC 4271 whose role is to discover Collision through the BGP RID and that he knows a Hello message to leave and what to do DROP.
exec
access-list 100 permit tcp any host 150.1.4.4
As we saw earlier, this problem can be solved by ebgp-multihop command and increasing the TTL value that will allow the establishment of neighborly contact.
Client-Peers
Note!
If we recall mechanism to prevent loops on BGP was the law - Split Horizon and was conducted by routing the resulting proliferation abode another IBGP IBGP neighbor, because that - Route Reflector breaking this law we need another mechanism to help prevent loops.
Hope i helped.
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