TheMgt wrote:
> Nick wrote:
>
>> I'm surprised that a VOIP connection works at all while STM is in place.
>
> My upstream gets throttled to 128Kb/s, still enough to carry a 64Kb/s
> a-law voice stream.
>
>> I was never under STM. My connection sucked because of congestion.
>

I thought STM used a method that dropped packets. I'm not sure this is
the case and would welcome a technical descriptions of how STM works.

> How do you know? VM's support groups are full of people asking if
> they're being STMed. They have to ask, otherwise how would they know
> it's not congestion or other network problems?
>

If you haven't download much and your upstream is 3 times the STM limit.
It seems like a no-brainer.

>> It is easy to spot STM because the upstream speed drops so significantly.
>
> Congestion can do that too.
>

It can but my experience was that the upstream did not drop anywhere
near as much as the downstream. More to the point it means if it doesn't
drop you know you are not being STMed.

>> If you don't approve of STM how do you think VirginMedia should manage
>> congestion?
>
> How about not rolling out speed upgrades until they have the network
> capacity to support them.
>

I think current costs for ADSL 1Mb/s are about £200 per month. I was
looking at the new BT ADSL provison quoting prices less than this but
still in the £100 region. VM has a different cost structure to BT but
the problem is still the same. Say VM can provide 1Mb/s for £50 a month,
If a substantial proportion of users start using that allocation the
network gets congested.

So if a 20Mb/s user pays £37 a month after profit and admin costs are
taken maybe £25 is left which can finance 1/2 Mb/s. Thus you cannot
profitably run at a contention ratio of < 40:1. The more bandwidth
hungry users get the more likely this figure causes congestion.

VM cannot just add network capacity to fix the problem.