[Ecn-sane] Meanwhile, over on NANOG...

[Toke Høiland-Jørgensen]

Luca Muscariello <muscariello at ieee.org> writes:

> TCP anycast fails in this case and I would not blame the load balancer for
> that.
> Some people will have a different opinion on that.
>
> The current Internet just does not support well these use cases.
>
> At the same time this DNS service is supposed to be used in a different
> way. So we may even blame the user? Toke in this case ?
>
> DNS anycast works as long as it uses UDP.
> The IP address returned by the resolver should be unicast and TCP should
> run over unicast addresses.
>
> Toke,  Looks like you are doing an HTTP GET directly toward an anycast
> address. This is where things are supposed to break and they break.

I was just using 1.1.1.1 as a convenient example because it's easy to
type. I get the same behaviour to an actual web site hosted on
Cloudflare (which is how I discovered it in the first place). Cloudflare
makes heavy use of anycast, including to its HTTP endpoints.

> If you traceroute over unicast addresses you should see the load
> balancer providing stickiness.

As I replied to Rod, the non-stickiness was indeed user error on my
part. The problem is that the load balancer is hashing on headers
including the ECN bits.

I guess I'll go reply to the NANOG thread... :)

-Toke