Re: hotmail not dealing with ECN

[Jamie Lokier]

David S. Miller wrote:
>  > Every single connection to ECN-broken sites would work as normal - it
>  > would just take an extra few seconds. Instead of "Hotmail doesn't
>  > work!" it becomes "Hrm... Hotmail is fscking slow, but Yahoo is fine. I'll
>  > use Yahoo". A few million of those, and suddenly Hotmail isn't so hot...
> 
> No, as explained in previous emails, no retry scheme can work.
> 
> Hotmails failing machines, for example, send RST packets back when
> they see ECN.  Ignoring valid TCP RST frames is unacceptable and
> Linux will not do that as long as I am maintaining it.

How about this for a deployment plan:

Ignore only _one_ RST frame (the first one), either per destination IP
address or per connection.  It's equivalent to a little "controlled"
network loss :-)

First SYN includes ECN.  Second and subsequent SYNs do not.

This won't provide the benefits of ECN on a heavily congested network,
but it is a start on a lightly congested one.  In a few months you can
flip the switch to stop ignoring RST frames and enable ECN on all SYNs.

-- Jamie