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Re: [LUG] ADSL testing

 

On Sat, 7 Jan 2012, Shaun Orchard wrote:

On 7 January 2012 11:03, Gordon Henderson <gordon+dcglug@xxxxxxxxxx> wrote:


And see my earler post... Over their wholesale network (assuming you're
not an an LLU line), then BT guarantees a minimum of 2Mb/sec for 90% of
the peak-time... (I think - can't find the reference right now, but it's
not far from that if it's not that)


Are you sure? Every time I had exchange contention issues, I was told by my
(fairly reputable) ISP that BT would not accept speed complaints unless it
was below something like 1200Kbps throughput (as reported by BT's
speedtester), at several times of the day. This was on a Max Premium line,
so logically it would be even less on a non-premium line (800kbit? I don't
remember).

I'm pretty sure, however, I can't find the actual documents on BTs site, but this is from the Entanet documentation:

  Our business packages meet the needs of business customers requiring
  generous monthly bandwidth allowances ranging from 15GB to 180GB, greater
  priority and business friendly bandwidth allowance times. Business
  packages include Elevated Best Efforts (EBE) where available, which
  guarantees a minimum throughput of 3Mbps over the BT network subject to
  line sync rate. This minimum level of service is guaranteed for 90% of the
  time over the busiest 3 hour period. Please note: the minimum download
  speed achieved depends upon the quality of the line. Where EBE is not
  available the Business package will provide an increased upload speed of
  up to 832kbps through the use of MAX Premium circuits.

and I understand the limit is 2Mb/sec for standard, residential level.

But then, even when you did get to that stage (and I had to throttle my
traffic to force it below that threshold because whenever I would run a BT
speedtest it'd conveniently report a speed of 1300Kbps, or whatever was
just above their arbitrary threshold), BT would take their time in fixing
it.

They (BT wholesale) were even prepared to send an engineer out to my house
when it patently is nothing to do with my line or equipment - a full 8Mbit
sync, no CRC errors, tried several different modems. I'm not paying £130
for someone to declare that it must be my equipment at fault. Eventually
after months (seriously) of scathing emails to BT Wholesale (via my ISP who
seemed willing to pass them along) they finally admitted it was congestion
and fixed it. Unsurprisingly I suddenly started getting 6+Mbit throughput.

You probably had a stuck BRAS profile. Also, you should not have been talking to BT directly, but via your ISP - they normally ignore end users, so you got lucky in the end.

Sadly, diagnosing a stuck BRAS is pretty easy, but BT seem to have it very hard to fix - AIUI, they removed some of the controls that the resellers used to have to let them do this and now insist that they jump through hoops to get it reset. My own, rather bitter experiences recently left me with a total lack of connectivity for 4 days after I'd gone though the proper process of waiting for 72 hours, etc. and BT having sent someone on-site too. (and finding no fault, then me having to fight to not pay their charges!)

However, do read this:

  http://revk.www.me.uk/2012/01/bypassing-congestion-on-carrier-network.html

Not so much the whole article, but the paragraph near the bottom which contains:

  "They have clearly stated they will happily put 400 ADSL customers (up
  to 7.15Mb/s each) on a 10Mb/s back-haul."

That's BT for you.

I'm just glad I don't have to deal with that anymore - FTTC has just been
made available in my village (thanks partly to the EU) and I got it
installed yesterday. Absolutely flies and BT supposedly guarantees
something like 16Mbit throughput.

15. IIRC.

But you still potentially have the same issues, it's just a shorter bit of copper. Fortunately, BT are doing away with the BRAS profile system on WBC (21CN) lines. Those of us stuck on 20CN are still at it's mercy though.

Gordon
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