Kitz Forum
Broadband Related => FTTC and FTTP Issues => Topic started by: jonnyt44 on September 08, 2015, 09:49:12 AM
-
Hey Folks
Just moved in to a new build property. BT were willing to provide me with a 17a Infinity service, unlike everyone else who said up to 38Mbps max only (and some neighbours have been told "fibre not available").
Anyway, I'm about 700m from the cab. I was expecting around 45-50Mbps however I seem to be syncing at the full 80Mbps :O!
> adsl status
adsl status
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 79995000 bps US Actual Rate : 19999000 bps
DS Attainable Rate : 81794208 bps US Attainable Rate : 26933000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 16 dB Cur SNR Margin : 6 dB
DS actual PSD : 7. 5 dB US actual PSD : 13. 4 dB
NE CRC Count : 12 FE CRC Count : 1
NE ES Count : 10 FE ES Count : 1
Xdsl Reset Times : 0 Xdsl Link Times : 1
ITU Version[0] : b5004946 ITU Version[1] : 544e0000
VDSL Firmware Version : 05-07-04-03-00-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 20 dB Far SNR Margin : 15 dB
CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da459
DSLAM CHIPSET VENDOR : < BDCM >
It would be appreciated if someone could "review" my stats and tell me if they are good/bad, and if I'm on the limit of anything bad happening.
I'm pretty sure BT ran a brand new cable to our site and we're the first to move in, so no interferance from others...yet
Note: Before I upgraded the firmware on my Draytek Vigor 130, my max attainable rate was around 87Mbps and the NE Current Attenuation was 12dB. This dropped to 82Mbps and 16dB respectively (as shown above) after reboot/update.
Thanks
-
Your sync speeds are very close to the maximum 80/20 so I would say you are much closer to the cabinet than you think, probably a maximum of 400 meters. Enjoy your speed. :)
-
Hey Folks
Just moved in to a new build property. BT were willing to provide me with a 17a Infinity service, unlike everyone else who said up to 38Mbps max only (and some neighbours have been told "fibre not available").
All Openreach FTTC services are using a 17a profile - 40/2, 40/10 and 80/20. The only difference is the maximum sync speed cap.
-
Your sync speeds are very close to the maximum 80/20 so I would say you are much closer to the cabinet than you think, probably a maximum of 400 meters. Enjoy your speed. :)
Yeah, I am 425m from the cab and my attenuation is 17dB
-
Your sync speeds are very close to the maximum 80/20 so I would say you are much closer to the cabinet than you think, probably a maximum of 400 meters. Enjoy your speed. :)
Yeah, I am 425m from the cab and my attenuation is 17dB
Cool, that's comparing to my "NE Current Attenuation 16dB"? What is "Far Current Attenuation 20dB". I don't really understand my stats sorry.
-
Do you see that you have two separate sections of statistics?
The first, headed ATU-R, relates to your modem (the Vigor 130) and the second, ATC-C, relates to the DSLAM/MSAN located in the cabinet.
The various abbreviations are: DS -- down stream, US -- up stream, NE -- near end, FE -- far end, BDCM -- Broadcom.
Never having used a Draytek Vigor 130, I think it best for me to allow someone else to "translate" both sections of the statistics.
-
When you say you're 700m from the cabinet, is that walking distance or line length?
-
It's actually the line length. As this was a new build property, I was fortunate enough to observe the Openreach work. I can literally trace the cable back to the cab. It's about 650m. I'm amazed I'm getting this speed!
It is, for most of it's length, a very straight line.
Higher grade cable maybe?
-
I suspect a combination of new copper, very low background noise and a low takeup in your area of FTTC, all contribute to your excellent connection speed.
There was another user on here who was in a situation very similar to yours: they had a full sync at around 750m from the cabinet, so it does happen.
I can't help but feel jealous as I'm 800m away and only getting 50Mb :P
-
you much closer than 700m as indicated by your attenuation :)
enjoy the speed :)
-
I'm jealous for both of your lines and i am 1000 meters away from fttc cab and only getting 35mbps, what a difference 200-300 meters makes to ones fttc stats :ouch:
-
you much closer than 700m as indicated by your attenuation :)
enjoy the speed :)
Attenuation isn't just down to speed distance though ;)
-
attenuation is nothing to do with speed in regards to the measurement.
-
attenuation is nothing to do with speed in regards to the measurement.
I meant distance :)
-
yeah copper quality plays a part as well. But that is a extremely low attenuation for 700m, must be out of this world copper :)
-
And I'm only 450 meters and only getting 45 Mbps :(
-
And I'm only 450 meters and only getting 45 Mbps :(
Indeed Ronski no two line are the same given an equal line length it must be down to conductivity crosstalk and other stuff that makes are lines so unique.
-
I think I'm quite possibly literally the only one using VDSL2 in the bundle, as Openreach ran a new bundle to our new development (in a new PVC duct) from the PCP (with the fttc cab next to it), where myself and next door are the only houses completed (and next door don't have fttc).
Since this is a development with nearly 50 houses being built, I think that I will see a drop over time :(
Regarding the attenuation figure everyone is talking about...is it the 16dB or the 20dB? Which is the important one?
Thanks
-
Ronski put in for a pair swap, I would :)
-
Regarding the attenuation figure everyone is talking about...is it the 16dB or the 20dB? Which is the important one?
Both are important! The smaller, the better. ;) Those two figures are upstream and downstream, respectively.
I like to regard the attenuation as the "electrical length" of the circuit as distinct from the physical length.
As an example, there are approximately 2400 metres (physical) between my modem/router and the (exchange located) MSAN. As a consequence my attenuation is 28 dB and 48 dB, respectively.
-
Regarding the attenuation figure everyone is talking about...is it the 16dB or the 20dB? Which is the important one?
Thanks
It does not matter jonnyt44 the attenuation on fttc is not a benchmark for distance to PCP cabinet it's only a very rough guide, we would go with the downstream attenuation as a start point.
-
Will joints and thickness of the copper affect attenuation? Is it possible BT have seen sense and installed heavier gauge copper?
-
Heavier gauge copper will probably have lower attenuation, but it's not a simple matter of lower DC resistance. At the frequencies we're talking about, skin effect is an important consideration (that's the effect whereby high frequencies tend to travel mainly in the outer skin of the conductor, not the core). I imagine heavier gauge copper will have lower attenuation because it has more skin.
There are many other high frequency effects which all contribute to the attenuation - inductance, capacitance, standing waves, etc. - so attenuation is never a simple matter to analyse.
-
Out of interest I just checked my distance to the cab and it is around 255m and I am seeing 17db attn down with a max possible of 77878kbps and actual 64320 so there is a lot more to this than meets the eye. My cab was full last year and I had to wait for it to be expanded before I could go FTTC so there must be quite a lot of FTTC users on it.
Stuart
-
Pah I'm 700m from the cab (confirmed by OR engineer) and I get a very flaky 33/5 connection, that's the effect aluminium has I guess!
-
Will joints and thickness of the copper affect attenuation? Is it possible BT have seen sense and installed heavier gauge copper?
yep thicker copper lowers attenuation.
-
I get the feeling that BT used thick good copper on my lines, which are something like five miles long. The thinking is that I wouldn't be getting the speeds I'm getting (DS sync rate of 2016-2144) without really good stuff being in use. That combined with a low noise level caused by the complete lack of humans and technology along the route once you get one mile away from the exchange.
-
Well...it's been nearly 2 weeks, and of course yesterday (or today), my sync has dropped. I think there was some digging on the BT ducts.
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 64343000 bps US Actual Rate : 19999000 bps
DS Attainable Rate : 64562400 bps US Attainable Rate : 25461000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 16 dB Cur SNR Margin : 6 dB
DS actual PSD : 8. 0 dB US actual PSD : 13. 3 dB
NE CRC Count : 5756 FE CRC Count : 577
NE ES Count : 870 FE ES Count : 508
Xdsl Reset Times : 0 Xdsl Link Times : 3
ITU Version[0] : b5004946 ITU Version[1] : 544e0000
VDSL Firmware Version : 05-07-04-03-00-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 20 dB Far SNR Margin : 15 dB
CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da459
DSLAM CHIPSET VENDOR : < BDCM >
Do you think there is a chance it will go back up? All the other stats look the same?? Anyone with better understanding of the stats like to chip in? :)
Just to compare, my initial stats were:
> adsl status
adsl status
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 79995000 bps US Actual Rate : 19999000 bps
DS Attainable Rate : 81794208 bps US Attainable Rate : 26933000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 16 dB Cur SNR Margin : 6 dB
DS actual PSD : 7. 5 dB US actual PSD : 13. 4 dB
NE CRC Count : 12 FE CRC Count : 1
NE ES Count : 10 FE ES Count : 1
Xdsl Reset Times : 0 Xdsl Link Times : 1
ITU Version[0] : b5004946 ITU Version[1] : 544e0000
VDSL Firmware Version : 05-07-04-03-00-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 20 dB Far SNR Margin : 15 dB
CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da459
DSLAM CHIPSET VENDOR : < BDCM >
Thanks
-
Annnnd after a sneaky reboot (via vigor 130 web admin), it's gone up again. Not to max though, but still better.
vdsl status
---------------------- ATU-R Info (hw: annex A, f/w: annex A/B/C) -----------
Running Mode : 17A State : SHOWTIME
DS Actual Rate : 69680000 bps US Actual Rate : 19999000 bps
DS Attainable Rate : 69445296 bps US Attainable Rate : 25274000 bps
DS Path Mode : Fast US Path Mode : Fast
DS Interleave Depth : 1 US Interleave Depth : 1
NE Current Attenuation : 16 dB Cur SNR Margin : 5 dB
DS actual PSD : 8. 0 dB US actual PSD : 13. 4 dB
NE CRC Count : 0 FE CRC Count : 578
NE ES Count : 0 FE ES Count : 509
Xdsl Reset Times : 0 Xdsl Link Times : 1
ITU Version[0] : b5004946 ITU Version[1] : 544e0000
VDSL Firmware Version : 05-07-04-03-00-07 [with Vectoring support]
Power Management Mode : DSL_G997_PMS_L0
Test Mode : DISABLE
-------------------------------- ATU-C Info ---------------------------------
Far Current Attenuation : 20 dB Far SNR Margin : 15 dB
CO ITU Version[0] : b5004244 CO ITU Version[1] : 434da459
DSLAM CHIPSET VENDOR : < BDCM >