cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 
Highlighted
Aspiring Contributor
688 Views
Message 1 of 15

Is my sync speed inappropriately capped?

Hi all,

 

I have a HH5A. Had Infinity 1 since Jan 2016, upgraded to Infinity 2 in October (higher speeds not possible on my line, but got a deal that made it cheaper than Infinity 1). I'm around 0.6m from the (Huawei) cabinet. Standard setup at the master socket, which has a Mk.3 faceplate.

 

Up until some point in November, I was syncing at approx 29-31k, max attainable approx 34-35k, with a downstream noise margin of approx 6-7. Then something happened in November (not in my home, to my knowledge) to improve line conditions.

 

After a week or two of the sync speed stepping upwards, I have been syncing at EXACTLY 34,958 ever since - it's always this sync speed, never higher or lower. This is with a downstream noise margin of approx 11. Max attainable is always around 43k. I often have what look like scheduled re-syncs at about 5am in the morning (with corresponding TR069 entires in the log) , but the line is rock solid in-between these.

 

Is it possible that my sync speed is being capped, but at a speed that is too conservative for the condition that the line has been in since November? If so, how I could get this changed?

 

Router stats (please ignore the uptime, I had to shut down the router due to some electrical work):

 

1. Product name: BT Home Hub

2. Serial number: +068543+NQ53423819

3. Firmware version: Software version 4.7.5.1.83.8.204.1.11 (Type A) Last updated 06/01/16

4. Board version: BT Hub 5A

5. DSL uptime: 0 days, 10:16:16

6. Data rate: 4759 / 34958

7. Maximum data rate: 4759 / 43966

8. Noise margin: 6.1 / 11.4

9. Line attenuation: 26.7 / 24.3

10. Signal attenuation: 26.8 / 21.5

 

Downstream BRAS profile shows as 33.84 Mbps.

 

 

Any help appreciated!

 

Thanks,

 

Graham

 

0 Ratings
14 REPLIES 14
Highlighted
Distinguished Sage
Distinguished Sage
682 Views
Message 2 of 15

Re: Is my sync speed inappropriately capped?

It could be poor line quality causing DLM (Dynamic Line Management) to decrease the connection speed to reduce the number of errors on the line.

 

Noise on phone calls can be one indication, interference pickup on your internal wiring is another cause.

 

Highlighted
Distinguished Sage
Distinguished Sage
668 Views
Message 3 of 15

Re: Is my sync speed inappropriately capped?

Yes, your line would appear to have been banded by DLM. In theory, the banding should be released if the line remains stable but in practice lines that have been banded remain stuck in that state. Unfortunately the only way to get a manual DLM reset is by an Openreach engineer visit that results in clearing a fault. However, you are very unlikely to be able to tell the difference between 35M and you posssible 44M

Highlighted
Aspiring Contributor
663 Views
Message 4 of 15

Re: Is my sync speed inappropriately capped?

Thanks Keith.

 

Quiet line test is just that - quiet. Extension wiring is in good condition, is connected properly at the master socket, and should be isolated from the DSL side by the Mk.3 faceplate. I know the faceplate makes a difference in my situation because when I installed it a few weeks after first connecting to FTTC, the sync speed did increase by a good few Mb/s.

 

In other words, no obvious issues in terms of noise.

 

Is there any way of finding out whether the DLM is protecting me from some non-obvious line conditions by intentionally limiting the profile, vs. the profile being stuck? The extra speed would be genuinely useful 🙂

 

0 Ratings
Highlighted
Distinguished Sage
659 Views
Message 5 of 15

Re: Is my sync speed inappropriately capped?

Unless you run something like my dsl web stats, you're unlikely to see what numbers of errors are recorded on the line and as such, if DLM classes your line as Green, Amber, or Red.

If you want to say thanks for a helpful answer,please click on the Ratings star on the left-hand side If the the reply answers your question then please mark as ’Mark as Accepted Solution’
Highlighted
Aspiring Contributor
647 Views
Message 6 of 15

Re: Is my sync speed inappropriately capped?

Thanks licquorice.

 

Given that I'm well within the parameters (other than a slower upstream) shown by the BT checker, I imagine I would be very hard pushed to swing an engineer visit.

 

If only there was an alternative way of trying a DLM reset...

 

 

VDSL Range A (Clean)37.327.47.45.425Available----Yes--
VDSL Range B (Impacted)32.117.66.93.713.1Available----Yes--
0 Ratings
Highlighted
Guru
644 Views
Message 7 of 15

Re: Is my sync speed inappropriately capped?

You may have initially seen a rise in your downstream sync and throughput due to the implementation of G.INP on the connection via your street cab, but it doesn't operate on the upstream path. So in real terms your line could be just "average" and submit to a number of errored second counts that breach "green flag" ... but G.INP is making the downstream path acceptible. Without seeing the proper linestats, hard to say whether that could be the case, sounds plausible though.
Highlighted
Aspiring Contributor
625 Views
Message 8 of 15

Re: Is my sync speed inappropriately capped?

Thanks RogerB. I did wonder whether G.INP was the enabler back in November.

 

So, the situation seems to be:

 

1. DLM is limiting sync speed, maybe correctly, maybe not

2. DLM cannot be reset without an engineer visit, which I'm unlikely to get

3. Only way of investigating further is to look for clues in detailed line stats, which for me would require new hardware

4. If I had those stats and it looked like there was a case for DLM to be reset, go back to step 2

 

So unless one of the moderators takes pity on me and my first-world problem, it looks like I'm stuck for now!

0 Ratings
Highlighted
Distinguished Sage
Distinguished Sage
616 Views
Message 9 of 15

Re: Is my sync speed inappropriately capped?

As stated previously, I would be extremely surprised if you could tell any difference in the real world if the banding was removed.
0 Ratings
Highlighted
Guru
600 Views
Message 10 of 15

Re: Is my sync speed inappropriately capped?

I agree. But as stated many times on here, the best way to make the best of your connection with Infinity is to use a decent router/modem. A Billion router with Broadcom chipset matching the architecture of the MSAN chipset will always be more reliable, providing you're on a Huawei dslam. My own connection was using interleave 8 and 4 when I got it ... since changing over modems it's doing interleave 4 with G.INP and level 2 upstream. An increase of 4mbits down and about 2 up, not a lot but throughput is smooth and errored second count well down to what it was. And you get the benefit of 2.4 and 5G wireless simultaneously if you want it. Not cheap though, nothing worth anything ever is. 😉
0 Ratings