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[strontium90]

Hi...after years of struggling with adsl max and artificially manipulating my target snr, about 3 weeks ago I got BT's "Faster Total Broadband" and got a speed of 19meg (the engineers JDSU) coming into the house and a profile of 18.63meg...speeds always in the 18meg bracket...until today...

I noticed the speed had dropped to 15/16meg and there had been no connection drop...I havent unlocked the openreach modem so can't see stats..

However, 5 mins ago, my sister (who lives about 300 yds from me) telephoned to say they had got BT Infinity this morning and a re getting 25meg...It was my own fault for telling them this service was available

Anyways, could my speed drop be due to contention? We live pretty rural...

Edit:- I can't find the link to asbokids unlocking procedure for the HG open reach modem with flashed firmware...can anyone post me a link?

[Bald_Eagle1]

Here's the link :-

Firmware & Graphing Scripts


I very much doubt that contention is the issue.

It is more likely due to distance from the cabinet & the condition/type of cabling used.

Attenuation & noise interference are the main deciding factors which will, to an extent, be dictated by the above.

These can only be determined via unlocked firmware, as you have gathered.


BT's speed test will provide the IP Profile speed, which should be 96.79& of sync speed.

[strontium90]

Reset the modem and Bt Homehub and new BT speed test shows my profile is down from 18.63 to 17 meg and my ping has doubled from 36ms to 80 ms...sounds like interleaving has kicked in...will I request It be turned off? (I'm a gamer)

[Bald_Eagle1]

There has been some talk of ISPs being able to request various profiles e.g. speed profile, stability profile, standard profile etc.

However, as far as we are aware, this has NOT been implemented (yet).
 
In the meantime, DLM is allowed to automatically set such things as sync speed / Interleaving depth, Target SNR etc.

DLM appears very aggressive when slowing things down, but very slow at speeding things up.

Ideally you would harvest your stats & graph them & compare them against your nearby sister's stats & graphs.

Due to the low FTTC speeds you report, I assume you are both already quite a distance from the cabinet (I assume you are both connected to the same cabinet?).

I would take a wild stab that you are around 1600m from the cabinet & your sister is 1300m from the cabinet.

If you are both a lot closer than that, it could suggest aluminium cabling and/or its connections being in poor condition.

[strontium90]

Thanks Bald Eagle....yep, the distances you quoted are pretty spot on....prior to FTTC I had problems aplenty with unknown REIN issues (I had guessed it was overhead powerlines) but Have had 3 week solid connection with no problems until this morning...pretty sure DLM has kicked in but it seems too much of a coincidence that it started at exactly the moment they (my sister) got hooked up...won't have time to unlock modem till next week...

[Bald_Eagle1]

One other thing to note:-

The connection can often re-sync at different speeds too quickly for ISP systems to notice (The HG612 only takes around 16 seconds to re-sync).

Thus, a new PPP session is not initiated.

A new PPP session is required to update BT's IP Profile detail.

Therefore, quite often a BT test will show low speed yet IP Profile is still high, which causes lots of confusion for may users.

To ensure the correct IP Profile is being reported, disconnecting & reconnectiong the router will initiate a new PPP session without rebooting the modem.
DLM is again very aggressive if "too many" modem Sync disconnections are seen, but does not care how many new PPP sessions are initiated via the router/hub.

When reporting unstable connections, this inability for ISPs to see all the real disconnections makes it hard to prove instability unless other records are maintained (from an unlocked modem).

You may well end up being very surprised by how often the connection actually re-syncs.

I was when I first unlocked my modem & I had a few heated discussions until my ISP eventually agreed that they cannot see all the disconnections.