In this deep dive introductory tutorial on The Three Napkins Protocol (or BGP as it is commonly known!) we take a comprehensive look at establishing eBGP & iBGP peerings, examine the validation and verification commands available such as “show ip bgp neighbors”, “show ip bgp summary”, and “show ip bgp”, discuss the three (3) BGP tables (Adj-RIB-In, Adj-RIB-Out, and the LOC-RIB), examine Wirehshark packet captures of the TCP session establishment, OPEN, KEEPALIVE, NOTIFICATION, and UPDATE messages, discuss and demonstrate the importance of the three (3) well-known/mandatory BGP path attributes AS_PATH, ORIGIN, and NEXT_HOP, configure next-hop-self to ensure reachability, show how to establish peerings using loopback addresses, configure eBGP multihop and Cisco’s recommended best practice of disable-connected-check, discuss the BGP Finite State Machine (FSM), and much, much more! This is all done through the lens of the Cisco Learning Labs Discovery #22 activity! Enjoy!