Re: RFC3168, section 6.1.1.1 - ECN and retransmit of SYN

[John Bradford]

> > What if the first SYN packet, or the response to it is lost, (which is
> > more possible on congested links, which is when ECN would be most
> > useful), and we disable ECN - then we loose out on functionality we
> > could have, and the work around is actually detremental to
> > performance.  Once 99% of internet hosts support ECN, we could be
> > loosing more than we gain.
> 
> How do you know this is the reason for the lost SYN?

We don't.

> What if other things caused the SYN to be dropped by some
> intermediate site?

Then we would be assuming the host didn't support ECN, when in fact,
it may well do.

> All the workarounds for ECN blackholes violate the protocol and
> cause more problems than they solve.

Which is exactly what I what I was providing an example of.

> That is why we refuse to implement them, and this is why the ECN
> RFCs mark the "suggested workarounds" as optional not required to
> implement.

Errr, so we agree then.  Cool.

John.