Broadband Related > Broadband Technology

bRAS profile - my experience

(1/3) > >>

kitz:
Thought I'd share a personal experience of bRAS profiling that seems to go against all that BT say should happen.
Bear in mind this is a 7dB att connection which has always sync'd at 8128 with an SNR Margin of around 14dB

---------------

On Sat evening I lost all my downstairs lighting - so trying to be efficient I replaced the fuse in the fuse box.  Duly armed with re-wired fuse I plugged it back in and BANG..  I temporarily lost power in the whole house.

Reset the master switch and everything came back up again aside from the lighting....  and my router.
Whilst waiting for someone to come to my rescue.. I tried to see what could be done about getting my router to resync to the exchange.
After about an hour it did...  but with disastrous results...  synced at 8000, lost sync.. sync at 7800, loose sync..  and downwards.. it went until by the time it got to around 4000 I gave up and unplugged it.

Anyhow chris came round - fixed the faulty light switch and turns attention to the router.. which is still having problems trying to sync.
Still the downward trend to 4000 ish with only 6dB Margin.
Was about to get the SAR out, when a final router reset managed to at last get a stable resync of 8128.

Do a BT performance test - IP profile set at 5000. :/
So me thinks thats me buggered for the next 3 days and interleaving.

However..  next day checks my IP profile and back up at 7150..  so what happened here seems to go against all the so called rules laid down by BT as to bRAS profiling.

~ It didnt take long for the lower IP profile to kick in.
~ Blip logic wouldn't have been applicable in this case because sync was down more than once and for more than a couple of hours in all.
~ Blip logic didnt kick in anyhow or I wouldn't have been lower profiled in the first place
~ IP profile set at 5000 despite me syncing at speeds that should in theory have profiled me at 3500
~ It didnt take 3 full days to see the increase back up to full sync speed (possibly 12 hours?)
... and thankfully I'm on FAST and don't have to play ISP <--> BT ticket tennis trying to get interleaving turned back off.

roseway:
That's certainly a weird series of events. You do hear occasional reports of IP profiles going back up almost immediately instead of waiting for three days (in fact it happened to me once) but the 5000 profile after syncing at 4000 is really quite odd.
Also odd is the behaviour of the router after the mains problems. Routers do seem to be very sensitive to mains glitches (cheap and nasty power supplies I presume) but I have no idea why they sometimes take so long to recover. I can't imagine what the 'healing' process is.

Eric

kitz:
>> You do hear occasional reports of IP profiles going back up almost immediately instead of waiting for three days (in fact it happened to me once)

Yes Ive seen this too... in fact I am beginning to wonder if its a "first offence" then the going back up could happen a lot quicker than for repeat offences...  All unproven - but something doesnt seem to be happening quite by the rules set out by BT.
I also synced in the 4000 region on at least 2 separate occasions with at least an hour in between, but it didnt seem to pick up on those.

Something for sure upset my router -despite it being plugged in to a power surge protected socket.

kitz:
BTW whilst on weirdness things occuring totally unrelated but several weeks ago I had a weird event occur with my latency.
I'd been doing a fair bit of testing which involved several reboots of my router... when all of a sudden my latency increased drastically.
My normal bbc pings of 16ms increased to nearer 40ms.

For 3 days solid latency I had an additional and rock solid additional 24ms added - no matter where I pinged. 
The problem only seemed to affect me and no-one else from my ISP.. although my router still reported me on FAST mode.

You can see the sudden increase and decrease on these l8nc graphs
(ignore the blue on the increase as I was downloading something at the time), but you can still clearly see the underlying yellow increase.
BT works in mysterious ways - perhaps it was a routing issue and for 3 days my connection went up via aberdeen and then down to devon before going on to london.  :-\


[attachment deleted by admin]

roseway:
That increase in latency does rather suggest that you had been interleaved temporarily, despite what the router reported. In theory that would have limited you to 7150kbps sync, but several people have reported full-speed sync after interleaving, so that rule isn't inviolate either. But you could also be right about routing of course. :-\

Eric

Navigation

[0] Message Index

[#] Next page