Cisco BGP identifiers (posted 2016-04-22)
One of the tiebreakers in the BGP best path selection algorithm is to prefer the path learned from a BGP speaker with the lowest BGP identifier. So how are BGP identifier selected when they're not configured explicitly?
I always forget whether it's the highest or the lowest IP address configured on a Cisco router. Turns out this is remarkably hard to find in Google, but if you know where to look it's in Cisco's IOS command reference: