Re: Spin bit discussion - where we're at

[Roland Zink <[e-mail]>]

Am 27.11.2017 um 08:03 schrieb Jana Iyengar:
> In addition to how the spin bit can be designed and used, I'd like 
> those taking on this effort to consider this question: Whatever 
> network management problem you're considering solving with a bit, what 
> does it take to solve this problem without the bit exposed? I'm asking 
> you to consider "zero-bit" solutions, or at least for a cost/benefit 
> analysis of developing solutions with and without the spin bit for 
> specific network management functions. Specifically,
>
> (i) What's impossible or very difficult to do, from a network 
> management perspective, of not having the spin bit? Note that I'm not 
> asking for what is and is not measurable -- not everything measurable 
> is useful. I'm specifically asking in terms of network management 
> functions, in practice, as used by operators. Some of this has been 
> addressed in the discussions/drafts I've seen, but I think it's most 
> useful when framed in terms of network management functions.
I want to express the question about manageability from a different 
angle. QUIC moves the congestion control from being a common 
functionality in the kernel to application functionality. It also hides 
the protocol handling of congestion from the network. This gives 
incentives for application developers to change congestion control to 
give their application an advantage over others. No special rights are 
necessary. Now the question is does QUIC provide enough manageability to 
avoid an Internet (or some part of it) breakdown when it is misused? Can 
it be shown that this can't happen?

> (ii) What are the alternatives for building the same functions without 
> the spin bit? Let's consider for a moment that the spin bit isn't 
> actually available in practice. What will operators do to continue 
> managing their networks? This might be expensive, but that's precisely 
> what I'm looking for -- the cost to operators of not having the spin 
> bit. For instance, active probes are a fine way to measure network RTT 
> within operator networks, and that is an alternative. There are surely 
> others too. Their costs and limitations are important to know about in 
> order to reason about their viability, so I'd like to see alternatives 
> considered.
Solutions that only work within an operators network are not enough when 
more than one operator is involved.

>
> I don't mean to start the discussion on this thread, but I'd like to 
> urge those going off to do the writing to consider these questions.
>
> - jana
>
>
> On Sun, Nov 26, 2017 at 11:26 AM, MORTON, ALFRED C (AL) 
> <[e-mail] <mailto:[e-mail]>> wrote:
>
>     Hi Brian, Stephen, Lars, Mark and all,
>
>     one join, one suggestion, and one question below.
>     see [ACM]
>     > -----Original Message-----
>     > From: QUIC [mailto:[e-mail]
>     <mailto:[e-mail]>] On Behalf Of Brian Trammell
>     > (IETF)
>     > Sent: Wednesday, November 22, 2017 5:59 AM
>     > To: Eggert, Lars
>     > Cc: Mark Nottingham; QUIC WG; Stephen Farrell
>     > Subject: Re: Spin bit discussion - where we're at
>     >
>     > hi Lars,
>     >
>     > > On 22 Nov 2017, at 11:35, Eggert, Lars <[e-mail]
>     <mailto:[e-mail]>> wrote:
>     > >
>     > > Hi,
>     > >
>     > > On 2017-11-22, at 11:01, Stephen Farrell
>     <[e-mail] <mailto:[e-mail]>>
>     > wrote:
>     > >> What I thought was being requested and what I do think is
>     reasonable
>     > >> is to document a privacy analysis for any quic protocol bits
>     that are
>     > >> visible to the path. Whether or not some or all of that text
>     ends up
>     > >> in some RFC is another day's work.
>     > > Lars wrote:
>     > > for the Spin Bit specifically, the intent was to permanently
>     capture
>     > the analysis the DT has done, so that when others review the
>     proposed
>     > Spin Bit specification, they can take that as a given and direct any
>     > further analysis to other aspects. It made sense to the chairs
>     that that
>     > specific analysis should become part of the Spin Bit
>     specification. I
>     > think we'd be open to a discussion on whether a broader document
>     > analyzing the QUIC wire image would be a better home for this.
>     The main
>     > point is for the work that the DT has done to be documented.
>
>     > Brian wrote:
>     > Okay. That's somewhat more reasonable than what I read the ask to be
>     > ("we're going to gate this on the people who care about this
>     doing some
>     > non-trivial amount of work"). Those of us who volunteer (help,
>     please,
>     > anyone? :) ) can certainly pull together what we have in a
>     single I-D
>     > and ask the WG what more it thinks it needs. To me all this
>     seems pretty
>     > clear, but I've been working on this topic for a while.
>     [ACM]
>     Having reached the end of the "Thanksgiving thread",
>     I'm scrolling back a few pages to join the task of
>     permanently capturing the work of the DT in an I-D (at least):
>     There should be lasting value in some of our findings
>     and IMO they are worthy of a persistent reference.
>
>     > Lars wrote:
>     > > For proposals other than the Spin Bit (I think I have seen
>     individual
>     > contributors at least mention "loss" and "congestion" bits, but
>     without
>     > much detail), we wanted to clarify that we'd like to see an
>     analysis and
>     > discussion of their privacy aspects to roughly the same degree
>     as the DT
>     > has performed for the Spin Bit proposal.
>     >
>     [ACM]
>     I suggest that this might be a different I-D, at least to start.
>     Question: Is there a privacy analysis of present ECN available?
>     (a search yielded many results with Missing: privacy)
>
>     regards,
>     Al
>
>