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 deleted (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!

I read somewhere that vectoring is more effective on 17a than on 30a.

If you're intent on hassling him then make it vectoring, it will benefit far more people.

Without searching was that not around April 2012?

I don't know, sorry Andrew. RONSKI and wombat may remember

In reply to a post by MrSaffron:

Without searching was that not around April 2012?

Yes, it was about 6 months before my FTTC order in Sept 2012.

The modem firmware's were updated autumn 2013, I think mine was Nov time, when the web interface went on my hacked modem.

In reply to a post by RobertoS:

I don't know, sorry Andrew. RONSKI and wombat may remember

Packages using 80/20 speeds may have become available formally in Spring 2012, I'm not sure of the exact date. Plusnet ran a trial with those speeds, which meant mine upgraded in February 2012, but I don't know how things went for the general public.

However, the cabinets were converted to the 17a profile in Autumn 2011. IIRC, the process was gradual.

My old line was affected by this profile switch... on the 8c profile, my old line suffered from errors and packet loss, and DLM intervened to drop the sync speed from 40Mbps to around 37Mbps. However, on the switch to the 17a profile, the adjustment to the frequency bands allowed my modem to sync at a full 40 without DLM intervention and without the errors & packet loss. That happened when the profile was switched in 2011, months before 80/20 services became available.

I got my fttc connection in August 2012, and that was when Plusnet officially launched their 80/20 product just as my cabinet went live. My cab was installed in February 2012 and I remember being frustrated by Plusnet not having an official 80/20 product, so it must have been available from others sometime in early 2012

Edited by R0NSKI (Sat 22-Feb-14 15:20:58)