You hit the nail on the head. Google only seems to announce a subset of their routes to the route servers, but does announce all routes (for some definition of “all”) to direct peers. I notice this every time I turn up a new IX and traffic heads off onto my backbone instead of the local IX.

I did a spot check and I get that /24 via my direct peering (along with the /16).

Justin Seabrook-Rocha
-- 



On Mar 2, 2020, at 12:40, Seth Mattinen <sethm@rollernet.us> wrote:

Anyone know why Google announces only aggregates via peering and disaggregate prefixes over transit?

For example, I had a customer complaining about a path that was taking the long way instead of via peering and when I looked I saw:

Only 172.217.0.0/16 over Any2 LAX

That plus 172.217.14.0/24 over transit

Any inquiries to Google just get a generic "we're not setting up any new peering but we're on route servers" response for almost a year now. Or is it because they don't send the /24's to route servers and I'm stuck until they finish their forever improvement project to turn up a direct neighbor?