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Re: multiplexing -- don't do it

From: Mike Belshe <mike@belshe.com>
Date: Mon, 2 Apr 2012 13:52:22 -0700
Message-ID: <CABaLYCs4gGT5KKmP+skJU8AWFDZS87oy8ijjXi7=jOHn1BcX6A@mail.gmail.com>
To: "Adrien W. de Croy" <adrien@qbik.com>
Cc: Amos Jeffries <squid3@treenet.co.nz>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
On Mon, Apr 2, 2012 at 1:43 PM, Adrien W. de Croy <adrien@qbik.com> wrote:

> ------ Original Message ------
> From: "Mike Belshe" mike@belshe.com
> On Mon, Apr 2, 2012 at 6:57 AM, Amos Jeffries < <squid3@treenet.co.nz>
> squid3@treenet.co.nz> wrote:
>> On 1/04/2012 5:17 a.m., Adam Barth wrote:
>> On Sat, Mar 31, 2012 at 4:54 AM, Mark Nottingham wrote:
>>>> On 31/03/2012, at 1:11 PM, Mike Belshe wrote:
>>>> For the record - nobody wants to avoid using port 80 for new protocols.
>>>>>  I'd love to!  There is no religious reason that we don't - its just that
>>>>> we know, for a fact, that we can't do it without subjecting a non-trivial
>>>>> number of users to hangs, data corruption, and other errors.  You might
>>>>> think its ok for someone else's browser to throw reliability out the
>>>>> window, but nobody at Microsoft, Google, or Mozilla has been willing to do
>>>>> thatů
>>>> Mike -
>>>> I don't disagree on any specific point (as I think you know), but I
>>>> would observe that the errors you're talking about can themselves be viewed
>>>> as transient. I.e., just because they occur in experiments now, doesn't
>>>> necessarily mean that they won't be fixed in the infrastructure in the
>>>> future -- especially if they generate a lot of support calls, because they
>>>> break a lot MORE things than they do now.
>>>> Yes, there will be a period of pain, but I just wanted to highlight one
>>>> of the potential differences between deploying a standard and a
>>>> single-vendor effort.  It's true that we can't go too far here; if we
>>>> specify a protocol that breaks horribly 50% of the time, it won't get
>>>> traction. However, if we have a good base population and perhaps a good
>>>> fallback story, we *can* change things.
>>> That's not our experience as browser vendors.  If browsers offer an
>>> HTTP/2.0 that has a bad user experience for 10% of users, then major
>>> sites (e.g., Twitter) won't adopt it.  They don't want to punish their
>>> users any more than we do.
>>> Worse, if they do adopt the new protocol, users who have trouble will
>>> try another browser (e.g., one that doesn't support HTTP/2.0 such as
>>> IE 9), observe that it works, and blame the first browser for being
>>> buggy.  The net result is that we lose a user and no pressure is
>>> exerted on the intermediaries who are causing the problem in the first
>>> place.
>>> These are powerful market force that can't really be ignored.
>> So the takeway there is pay attention to the intermediary people when
>> they say something cant be implemented (or won't scale reasonably).
> I agree we should pay attention to scalability - and we have.
> Please don't disregard that Google servers switched to SPDY with zero
> additional hardware (the google servers are fully conformant http/1.1
> proxies with a lot more DoS logic than the average site).  I know, some
> people think Google is some magical place where scalability defies physics
> and is not relevant, but this isn't true.  Google is just like every other
> site, except much much bigger.   If we had a 10% increase in server load
> with SPDY, Google never could have shipped it.  Seriously, who would roll
> out thousands of new machines for an experimental protocol?  Nobody.  How
> would we have convinced the executive team "this will be faster", if they
> were faced with some huge cap-ex bill?  Doesn't sound very convincing, does
> it?  In my mind, we have already proven clearly that SPDY scales just fine.
> But I'm open to other data.  So if you have a SPDY implementation and want
> to comment on the effects on your server, lets hear it!   And I'm not
> saying SPDY is free.  But, when you weigh costs (like compression and
> framing) against benefits (like 6x fewer connections),  there is no
> problem.  And could we make improvements still?  Of course.  But don't
> pretend that these are the critical parts of SPDY.  These are the mice nuts.
> For a forward proxy, there are several main reasons to even exist:
> a) implement and enforce access control policy
> b) audit usage
> c) cache
> you block any of these by bypassing everything with TLS, you have a
> non-starter for corporate environments.  Even if currently admins kinda
> turn a blind eye (because they have to) and allow port 443 through, as more
> and more traffic moves over to 443, more pressure will come down from
> management to control it.
> Best we don't get left with the only option being MITM.

In my talk at the IETF, I proposed a solution to this.

Browsers need to implement SSL to trusted proxies, which can do all of the
a/b/c that you suggested above.  This solution is better because the proxy
becomes explicit rather than implicit.  This means that the user knows of
it, and it IT guys knows of it.  If there are problems, it can be
configured out of the system.  Implicit proxies are only known the the IT
guy (maybe), and can't be configured out from a client.  The browser can be
made to honor HSTS so that end-to-end encryption is always enforced

Further, proxies today already need this solution, even without SPDY.
 Traffic is moving to SSL already, albeit slowly, and corporate firewalls
can't see it today.  Corporate firewall admins are forced to do things like
block facebook entirely to prevent data leakage.  But, with this solution,
they could allow facebook access and still protect their IP.  (Or they
could block it if they wanted to, of course).

Anyway, I do agree with you that we need better solutions so that we don't
incur more SSL MITM.  Many corporations are already looking for expensive
SSL MITM solutions (very complex to rollout due to key management) because
of the reasons I mention above, and its a technically inferior solution.

So lets do it!


> Adrien
> Mike
>> With plenty of bias, I agree.
>> AYJ
Received on Monday, 2 April 2012 20:52:51 UTC

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