[Iccrg] congestion control and visability to the user

[michawe at ifi.uio.no]

Hi, Mikael,

You said:

> The customer is paying for a certain access to The Internet, congesting in
> the core basically is a breach of contract. The only congestion on a well
> behaved network is on the access line (PE-CE link).

and:

> I guess your view of the wolrd and mine differes widely. I don't agree
> with you at all. ISPs congesting their cores are doing a bad job and
> should be punished for it.

For a minute, assume that all users have an extremely
well working congestion control mechanism, which would
allow them to completely saturate their PE-CE links
(from what Matt says, I gather that we're moving towards
such a situation, as - I think - we should)

Do you, then, assume that core network capacities have
to match all this traffic, i.e. be up to N * PE-CE capacity
when N is the number of customers?
(I'm assuming an extremely inefficient net layout here  :)
but I think you get my point)


>> I didn't realize how bad it might be until I had a conversation with
>> my son, who mused that he liked his new PC because it was so quick on
>> the network.  However, whenever he is doing anything serious (he is a
>> web designer), everybody else on his home LAN starts to complain.
>
> That is the PE-CE link I was talking about. The PE-P-PE links should never
> go full, then they're not capacity managed correctly. The PE-CE link is
> designed to be a limiting factor (that's what you pay for) and THERE is
> where the intelligent queueing needs to be (or have really small buffers
> that saw-tooth bulk TCP performance so the smaller capacity interactive
> flows have a high probability of succeeding in getting their traffic
> thru).

I agree on that. Since you were in the Stockholm IETF,
you must have seen my Ph.D. student Dragana's presentation,
which addressed exactly that:
http://www.ietf.org/proceedings/75/slides/iccrg-1/iccrg-1_files/v3_document.htm
(it seems that her only diagram hasn't survived the conversion,
but it should be understandable anyhow)

Cheers,
Michael
(also pronounced "Mikael" by most people in these
parts of the world btw  :-)   )