BGP doesn't discover neighbors automatically. You must configure each peering explicitly.
Configuring a peer requires:
- Neighbor's IP address
- Neighbor's ASN
- Your router's BGP configuration
Session establishment:
TCP connection on port
Exchange OPEN messages
If parameters acceptable, session becomes Established
Exchange routes via UPDATE messages
Send KEEPALIVE messages periodically
Why TCP? BGP needs reliability. Lost routes cause traffic black holes.