Re: [Unbearable] Ben Campbell's Yes on draft-ietf-tokbind-negotiation-12: (with COMMENT)

[Ben Campbell <[e-mail]>]

> On May 9, 2018, at 4:05 PM, Eric Rescorla <[e-mail]> wrote:
> 
> 
> 
> On Wed, May 9, 2018 at 1:05 PM, Ben Campbell <[e-mail]> wrote:
> Ben Campbell has entered the following ballot position for
> draft-ietf-tokbind-negotiation-12: Yes
> 
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> Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html
> for more information about IESG DISCUSS and COMMENT positions.
> 
> 
> The document, along with other ballot positions, can be found here:
> https://datatracker.ietf.org/doc/draft-ietf-tokbind-negotiation/
> 
> 
> 
> ----------------------------------------------------------------------
> COMMENT:
> ----------------------------------------------------------------------
> 
> Thanks for this document. I am balloting "yes", but have a few comments:
> 
> - I support Alexey's DISCUSS. Additionally, do I understand the version
> negotiation to require the client to support all previous version from the one
> it initially advertises? If so, how would you deprecate a version at some time
> in the future?
> 
> You can't do it in the CH. The assumption is that the server will pick the highest
> common version in the SH and if you don't support that, you abort.

Just to make sure I understand: If the client selects version N (ignoring the (major, minor) format for a minute) , the server might respond with N-1. If the client doesn’t like N-1, it aborts and optionally tries again with the highest version it supports that is lower than N-1? Or should it just give up on TB?

Thanks,

Ben.