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

[Joe Touch <[e-mail]>]

On 5/5/2014 9:36 AM, John Leslie wrote:
> Joe Touch <[e-mail]> wrote:
>> On 5/5/2014 7:41 AM, John Leslie wrote:
>>>
>>> (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.)
>>
>> It had that warning when it saw the EDO option and decided that it could
>> ignore it quietly.
>
>     This points out another failure of the TCP-Options design: for such
> a basic building block, Options should have carried an indicator of
> what to do with an unrecognized option -- e.g. ignore, drop the packet,
> etc.

Right - we built that into IPv6, but TCP missed that boat.

However, it still requires that middleboxes would do the right thing; 
their incentive to "keep working" suggests they would treat this like 
all other Internet standards - something to violate if it makes them money.

So even if the flag were there (it sort of is already - but "ignore" on 
pass-through should have been interpreted as "drop"), it's not clear 
middlebox vendors would do as we proscribe.

Joe