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

[Wesley Eddy <[e-mail]>]

On 5/5/2014 10:41 AM, John Leslie wrote:
>> 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. 
>
>    (That's one of the reasons I prefer to have "Data Offset" be a clearly
> invalid value whenever it is overridden by EDO: any middlebox will then
> have fair warning that it is clueless.)
> 


I think I agree.  IMHO, the tradeoff comes down to whether it's more
desirable for the middlebox to end up doing something violent like:

- dropping the segment
- resetting the TCP connection
- generating an ICMP
- crashing

versus just doing something to the segments which the receiver can
detect and possibly work-around with greater size and complexity in
the mechanism itself.

It ends up being a matter of transition and whether we really
expect offending nodes to be found and fixed over time, and can
stand some deployment hassles and complaints in the meantime.
If not, then the design needs to be a bit more complicated forever
in order to accommodate today's legacy.

If there are significant advantages to being able to use long
options that relate to real business problems, then I think the
legacy won't be as much of a problem, but don't really know.

-- 
Wes Eddy
MTI Systems