Is there any data on packet duplication?

Saku Ytti saku at
Tue Jun 23 05:21:31 UTC 2020

On Tue, 23 Jun 2020 at 08:12, William Herrin <bill at> 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

STP doesn't help, at all. Hope this helps.


More information about the NANOG mailing list