On Tue, 23 Jun 2020 at 08:12, William Herrin <b...@herrin.us> wrote: Hey Bill,
> That's what spanning tree and its compatriots are for. Otherwise, > ordinary broadcast traffic (like those arp packets) would travel in a > loop, flooding the network and it would just about instantly collapse > when you first turned it on. Metro: S1-S2-S3-S1 PE1: S1 PE2: S2 Customer: S3 STP blocking: ANY S3 sends frame, it is unknown unicast flooded, S1+S2 both get it (regardless of which metro port blocks), which will send it via PE to Internet. STP doesn't help, at all. Hope this helps. -- ++ytti
