Should I expect more...

Been with Uno on a VDSL2 connection over 2 years every since moving into a new build. Connection has been reliable and support is quick in responding.

However I've had a long nagging feeling about download speeds I'm getting.

Connection speeds have been stable for over 18 mths. circa 60 Down, circa 16 Up. Checking tonight connection is 60.7mbps DL / 17.2mbps UL.

Through numerous speedtests (I check once or twice a week at different times) I get 15-16 up but normally only 43-45 down. Once (and I mean once) I got 53 down but never more.

Comparing to family who live on the other side of town whose connection is at max speeds (79.9 DL/18.5 UP) I get 74-76mbps download using the same speedtest sites on their network.

I've raised with support a couple of times over the last year. Their response has been very dismissive of speedtest.net stating results are unreliable and therefore they won't consider them -although I have to say I find the Vodafone UK London server very consistent.

If it was local temporary congestion at the cabinet or exchange I would expect the DL speed to fluctuate low and high but it doesn't. If I didn't know better I would have guessed its some kind of quality service throttling at the ISP but Uno has dismissed this as well.

Using their own speedtest tool on their customer portal registers 51-53. They feel that is reasonable for the connection speed and do not believe there are any faults. I'm a little skeptical about the accuracy of their speedtest tool. It doesn't reflect the speeds I've seen from download local mirrors & various speedtests.

The only option they have offered is to arrange an Openreach engineer visit but noting they are not seeing faults and their own speedtester results they state I would have to pay c. £150 if the engineer doesn't find a fault - not particularly compelling risk to take.

So...

If speedtests return 76mbps from 80mbps connection, is it reasonable to only get 45mbps from 60mbps? Should I expect more? If I should, what speeds should we expect?

I'm out of contract so could move. If I moved could I expect higher DL speeds or if I'm seeing this problem with Uno are we just as likely to see it with someone else?

Some speedtests results I've taken while writing this...

TB Speedtest
Speedtest.net #1
Speedtest.net #2

How are you connecting to the router? Wireless or ethernet? I would try another router first and just rule that out before going down the network route.

I am with Uno on a Fibre+ package (BT Wholesale based) and sync at the full 80/20. Generally I am getting around 70/17 on various speedtests at the moment. Running the following on iperf3 also returns 70.2Mbps on average.

70Mbps on a 80Mbps is a factor of 0.875x, which on a 60Mbps connection gives you 52.5Mbps - which is coincidentally around the same speeds you are seeing.

I decided to do a bit more digging and ran a full diagnostic on http://speedtest.btwholesale.com. The results were quite interesting.

Download speed achieved during the test was - 69.84 Mbps
IP Profile for your line is - 73.7 Mbps

My cabinet has vectoring enabled and I generally have an attainable rate of 95/22 most of the time, meaning a steady sync of 80/20 is achieved. I can't quite therefore understand why my IP profile is just 73.7 Mbps, especially given FTTC profiles are supposedly meant to be ~96.8% of your sync speed.

That goes some way to explaining the slightly reduced bandwidth, although I still seem to be missing ~3Mbps somewhere.

That's normal.
Retransmission High has an I.P profile between 91-92%

I'm synced at 75/20 and get 69/19 on speedtest.net.

Downstream loss of ~15 seems high to me. Is it the same in the middle of the day/night?

There is/was a tool to check your BT BRAS IP profile here: https://windows.mouselike.org/be/index.asp?DoAction=...

Who's your provider? They might be applying a different rate-shaping profile on their BRAS.

I see similar somewhat contradictory results here on BT with a cabled connection.

Sync: 80.00/20.00 (Attainable 83623/25468, used to be so much higher when less users on the cab)
BRAS Rate: 70.56/20.00
TB Speedtest (ipv6): 67.69/18.1 to 19.7 unusually fluctuating a bit)

I'm unclear as to why the download BRAS rate is 88.2% of sync whereas upload is the same (100%)

In reply to a post by MCM:

I'm unclear as to why the download BRAS rate is 88.2% of sync whereas upload is the same (100%)

It's because the BRAS doesn't need to do any shaping on the uplink direction.

The downstream shaping is done because the xDSL line is a bottleneck:

INTERNET ===> BRAS ===> DSLAM -----> end-user

The speed between the DSLAM and the end user's router is limited. The DSLAM is pretty dumb, and if you send it packets faster than it can deliver them, it will just throw them away.

The BRAS is smarter: it can limit the speed at which it sends packets to the DSLAM, and buffers any excess if data arrives faster than this. This leads to smoother performance, avoiding lots of unnecessary TCP retransmits for example.

There is L2TP/RADIUS magic by which the DSLAM signals to the BRAS what sync speed it has achieved, and the BRAS has to set a lower limit based on the usable throughput (sync speed minus overheads).

However in the reverse direction, there's no problem as you're going from narrow channel to wide channel:

INTERNET <=== BRAS <=== DSLAM <---- end-user

The BRAS receives packets as fast as the DSLAM can send them, and dumps them straight out to the Internet. Any outbound buffering would be done in the end-user's router.

Thank you and understood. I'm still unclear though as to why my BRAS/sync ratio is 88.2% (FastPath, Huawei). I thought this was normally around the mid 90s or a little higher.

I have around the same sync rates, (theoretical max) but that checker says ......

The current Downstream BRAS rate is: 73.7 Mbps
The current Upstream BRAS rate is: 20 Mbps

... I used to get max rate at my old place too, but could often hit 75/76 on download.

Dark magic, that�s what it is.

In reply to a post by MCM:

Thank you and understood. I'm still unclear though as to why my BRAS/sync ratio is 88.2% (FastPath, Huawei). I thought this was normally around the mid 90s or a little higher.

Do you have G.INP on your line (also called retransmission)? That lowers the IP profile.

Retransmission Low gives an IP profile that's ~96.69% of the sync speed.
Retransmission High gives an IP profile that's between ~91-92% of the sync speed.