Re: [tcpm] New Version Notification for draft-touch-tcpm-tcp-edo-01.txt

[Joe Touch <[e-mail]>]

On 5/5/2014 12:49 AM, Costin Raiciu wrote:
> I'd like to add to what Olivier has said.
>
> One question I had about this draft is whether the options included
> in the EDO are supposed to be carrying sequence numbers or not. Two
> options:
>
> 1. they carry sequence numbers: in this case we are changing the
> semantics of options in TCP, sending them reliably, orderly and
> subject to flow control.

We're not doing that any more than the options in existing segments 
within the existing Data Offset are so covered.

The option isn't buried in the data stream - this was considered for 
MPTCP, but rejected, for some of the reasons you mention.

So EDO option space ought to be used the same way - with the same 
limitations (or not) of existing option space.

...
> Another thing: the draft says that NAT will work with EDO. However,
> most NATs have a passive FTP mode - which means they will look
> through the TCP payload for the host's IP address and rewrite with
> their own. With EDO, the NAT could be messing up options placed in
> EDO space in the payload. To avoid this you need a checksum, as
> Olivier says.

See my response to Oliver's issue on this. Such a NAT ought to have 
either dropped the EDO in the initial SYN or dropped the SYN completely.

Joe