Infinity 2: Download vs Upload

I have only just got around to posting this, but I am on BT Infinity Option 2 and a few months ago my line's performance seems to have changed.

Historically I always got 74.x Mbit download speed and 16.x upload. Since this change occured - whatever it was - I now always get 69.x download and 18.x upload.

Is this normal - have BT changed how much bandwidth they are allocating for upload or something? This doesn't really matter to me, I am just interested. If I was chosing, I'd rather have the faster download speeds, since I rarely if ever upload anything substantial. But I do download the odd gigabyte+ file every now and again when the extra download bandwidth would be handy.

I don't suppose there's anything I can do to change it back, is there?

BTW - none of my equipment has changed. And I have rebooted modem and router over the ensuing weeks and its made no difference.

I should say, I am very close to the FTTC cabinet and the BT checker says I should get download of between 72 and 76MBit and upload of between 20Mbit and 20Mbit. So the line is slightly underperforming compared to BT's estimates.

Edited by Chippy_boy (Tue 18-Feb-14 15:19:14)

No changes to the VDSL2 profile underlying, but if may be that crosstalk has changed, and impacting downstream more now, but upstream less. Or a firmware upgrade to the Openreach modem has adjusted how it behaves.

Note the 20 Mbps is the line connection speed, so once you allow for inefficiencies in yourTCP stack and modem and router the 18.x is pretty much the top speed. Highest seen is around 19.5 Mbps.

Interesting, thank you.

I am tempted to believe the modem firmware update answer. The speed has been so consistent and rock solid and the change so sudden, it would seem odd for there to be some step change in noise/crosstalk. And also it would seem strange that this could somehow improve upload speeds.

I had wondered if perhaps BT are now allocating more bandwidth to upload with more and more people having cloud backup solutions such as BT Cloud.

Still, I can live with 69.7MB download and 18.7MB upload. But 300MB Infinity 4 FTTH would be nice

They are running Profile 17a currently. The next one that will boost upstream is Profile 30, i.e. jumps from using up to 17MHz to up to 30 MHz and no sign of a roll-out of that yet.

I had a similar experience... I was the first on my cabinet, by about a month, and I synced at the full rate. Then the neighbours found out about FTTC and crosstalk has seen my attainable sync drop from 100Mb to 70Mb. The stats I collected from the modem could be linked pretty much to a visit to one of my close neighbours houses...

I can rule out the modem firmwares because I have an ECI and Huawei and they both sync pretty much at the same value. I'd wager something similar might have happened to you.

Thanks
Tim

A new user on your cabinet with a pair running along side yours can easily change the noise levels from crosstalk and a step change would be reasonable in those cases.

In reply to a post by Chippy_boy:

I am tempted to believe the modem firmware update answer.

Yes the openreach modems had a firmware update in the autumn last year. Those with hacked Huawei modems saw the version change. It has improved performance for some users (such as myself) who don't get the full sync speeds.

It may depend on what you mean by "historically".

The original rollout used VDSL2 Profile 8c. I believe the change to 17a shifted certain frequencies around between download and upload. This could have caused the effect you observe.

In reply to a post by MrSaffron:

They are running Profile 17a currently. The next one that will boost upstream is Profile 30, i.e. jumps from using up to 17MHz to up to 30 MHz and no sign of a roll-out of that yet.

Not only no sign of rollout, but no sign at all. The modem specification for DP-supplied kit is 17a plus 17Mhz vectoring.

In reply to a post by MrSaffron:

They are running Profile 17a currently. The next one that will boost upstream is Profile 30, i.e. jumps from using up to 17MHz to up to 30 MHz and no sign of a roll-out of that yet.

I might ask BT CEO to get this roll out this year possible!