Re: [tcpm] More TCP option space in a SYN: draft-briscoe-tcpm-syn-op-sis-02

[Joe Touch <[e-mail]>]

On 9/25/2014 2:56 AM, Bob Briscoe wrote:
> Joe,
> 
> At 23:25 24/09/2014, Joe Touch wrote:
>> Hi, Bob (et al.),
>>
>> It's good to have a more detailed description of the proposal.
>>
>> I still find a dual-SYN solution untenable, though, as it has been for
>> other upgrade paths in the past (e.g., IPv6).
> 
> That's why I prefer syn-op-sis because it only uses 2 SYNs for transition.
> 
> I've included a new section on ways to use only 1 SYN during transition
> (building a white-list) and ultimately moving to 1 SYN in the future,
> only falling back to the legacy SYN in series rather than parallel if
> you hit a legacy listener.
> 
> The other two in tcp-syn-ext-opt have to be 2-SYN for ever.

But they don't both use two SYNs. One (that I prefer) uses an additional
out-of-band segment.

IMO, using two SYNs is problematic - regardless of whether the upgraded
system uses both or just one.

IMO, we're going to be dealing with legacy TCPs for a *very* long time.

Time for others to jump in ;-)

Joe