In reply to a post by WilliamGrimsley:

According to the Hub, you're on a very short line. But, the downstream rate is banded and the maximum downstream rate is very low.

These conclusions are erroneous. 25dB attenuation is not a very short line - it's moderately long (I'll leave it to others who are more experienced than I to guesstimate how long it is). The Hub is mistakenly reporting sync speeds in kbit/s that are clearly in Mbit/s - 35 Mbit/s at 4.7dB SNR margin is maybe a little low but not very low compared to expectations.

Your suggested debug steps are reasonable - though when plugging in to the test socket, you should ensure there is no dial tone on any other sockets, as it is always possible that one or more extensions is mistakenly connected to the 'wrong' side of the NTE5.

Ah, whoops! My bad! I thought that the noise margin value was the line length value, but it's not! Haha! The lower downstream SNR margin is likely to be caused by either the modem connecting at a less noisy time or before more crosstalk was created by new connections to the cabinet.

That's true, but we don't know if the OP has any extension sockets, so I didn't suggest that.

Edited by deleted (Thu 06-Apr-17 08:20:50)

Oh, I never said that the issue is with the router.

There's evidence right here on this thread! Look at the data rate, it's reported in Kbps not Mbps, that's one piece, oh and the rest well you can find loads in the its log or simply search around on the BTCare Community Forums.

If the OP doesn't wish to book a broadband boost engineer to remove the downstream banding, then I recommended that option as a router such as a Billion BiPAC 8800AXL will correct more errors and resync less, encouraging DLM to remove the banding automatically.

Edited by deleted (Thu 06-Apr-17 08:31:40)

Based on the analysis some time ago from a trawl of all the attenuation/sync data I could find the average works out that sort of range, with 7.5 to 8 Mbps on the upload side

Just as with ADSL2+ of years gone there is the average and the small number of edge cases that seem to buck the trends, but with VDSL2 that can be explained by them being lucky and not having much cross talk potentially

Agreed! But, looking at the stats, there is definitely downstream banding present, proven by the OP saying that the Hub connects at the same downstream rate.

Edited by deleted (Thu 06-Apr-17 11:23:41)

Thank you for all your input. However, my knowledge is limited on this subject so not sure what "banding" is. Is it similar/the same as IP Profile where BT's system restricts the speed? If so does it look like they are doing that and could I it go to a higher download speed. As I said at the beginning, my HH6 always reconnects at 35 mbps download, although the log seems to suggests it could be as high as 46 mbps.It just seems a bit odd to me.

Thanks once again.

John

Banding is a way of dealing with excessive error rates on FTTC.

On ADSLx it was done by raising the sync-time SNR Margin. This reduced the sync speed so decreased the number of errors. On FTTC it is done with a straight "banding" of the sync speeds. Setting an upper and lower limit.

See BT SIN 498, Para 2.2.1.

AFAIK, it is still SNR margin then banding. That's what I saw with my connection. I think Openreach should've brought over the intervention part of the DLM system on ADSL to VDSL!

Edited by deleted (Thu 06-Apr-17 21:53:09)

Not so easy with FTTC frequency profiles. On ADSLx the upstream and downstream were each contiguous ranges, but the FTTC specifications are for multiple interleaved bands.

Shame. Ah well, at least on the most part, an EU can request a DLM reset which is conducted normally a few days afterwards.

Edited by deleted (Thu 06-Apr-17 21:55:13)