Re: [conex] Potentially interesting ConEx problem

[Matt Mathis <[e-mail]>]

Bob, I do know how to do it from the ISP's vantage point.

It is a bit harder from the content provider's vantage point.   A
large content provider might, for example, want to be able to
distinguish between appropriately filling subscriber links and
aggravating some capacity failure elsewhere along the path.
Traditional serving optimizations actually make this problem far
worse: serving from as many places as possible, as close to the users
as possible makes the system even more brittle to ISP failures.

There is not an easy way to do this today.  There are inference
signals (e.g. correlated losses across flows) but the signals are
expensive and slow.

Thanks,
--MM--
The best way to predict the future is to create it.  - Alan Kay

Privacy matters!  We know from recent events that people are using our
services to speak in defiance of unjust governments.   We treat
privacy and security as matters of life and death, because for some
users, they are.


On Tue, Mar 5, 2013 at 1:53 AM, Bob Briscoe <[e-mail]> wrote:
> Matt,
>
> The solution to the access link part of this problem is explained in:
> <http://tools.ietf.org/html/draft-briscoe-conex-initial-deploy-03#section-4.1.1>
>
> It can only distinguish access link congestion from shared congestion.
> Distinguishing home network congestion is harder, but possible with a tunnel
> to the home router, which already exists in some DSL arrangements (e.g. in
> BT we use a tunnel for services that share a line).
>
>
> Bob
>
>
> At 22:18 04/03/2013, Matt Mathis wrote:
>>
>> I have an interesting problem that I wish ConEx could solve, but I
>> don't see how.   I want to distinguish between congestion on the path
>> between a server and a subscriber aggregation point (e.g. DSLAM etc)
>> and congestion beyond the aggregation point (e.g. the access links
>> themselves, or the user's home network).
>>
>> There are some ways to infer this, but as far as I can tell there is
>> not a reasonable way to measure it directly.   This is a problem that
>> we have touched on in the past, but I don't recall discussing any
>> solutions.
>>
>> Thanks,
>> --MM--
>> The best way to predict the future is to create it.  - Alan Kay
>>
>> Privacy matters!  We know from recent events that people are using our
>> services to speak in defiance of unjust governments.   We treat
>> privacy and security as matters of life and death, because for some
>> users, they are.
>
>
> ________________________________________________________________
> Bob Briscoe,                                                  BT