Bt Infinity 2, HH5: Are my connection stats normal?

Hi All,

Got Infinity 2 installed about 4 weeks ago. I'm really close to the cabinet, and I kind of expected to be connecting at full speed. However, my download is hovering around 70 - 72 (line 6 Data Rate), and I'm concerned that my line might be sub optimal.

Can anyone comment on the stats below?

1. Product name: BT Home Hub
2. Serial number: +068343+NQ44103035
3. Firmware version: Software version 4.7.5.1.83.8.204 (Type A) Last updated 27/01/15
4. Board version: BT Hub 5A
5. DSL uptime: 0 days, 00:01:54
6. Data rate: 19999 / 71621
7. Maximum data rate: 24055 / 70937
8. Noise margin: 15.2 / 6.3
9. Line attenuation: 22.1 / 17.2
10. Signal attenuation: 22.1 / 17.2

Thanks,
Mike

Why the low connection time?
You don't want to keep rebooting the Hub.

Also if your cabinet has loads of people all using their connection then this will cause noise which reduces your speed in effort to reduce errors.

Also what is really close?

Paul

Hi Paul,

I literally just did a full power-off and reboot to see if it would sync up faster. (based on reading some advice in the forum), so no. I've not been rebooting like mad. Prior to then, it was last rebooted on the 26th Jan.

I was the first person connected to the cab. (It is a brand new one outside an exchange, one of the few EO conversions). Distance: I'd guess between 150 to 200m to the cab. (The installer was also confident that based on the distance that I'd get full speed)

Mike

In reply to a post by mramcha:

Hi Paul,

I literally just did a full power-off and reboot to see if it would sync up faster. (based on reading some advice in the forum), so no. I've not been rebooting like mad. Prior to then, it was last rebooted on the 26th Jan.

Ah, ok.
I learnt the hard way with our ADSL2+ connections

In reply to a post by mramcha:

I was the first person connected to the cab. (It is a brand new one outside an exchange, one of the few EO conversions). Distance: I'd guess between 150 to 200m to the cab. (The installer was also confident that based on the distance that I'd get full speed)

Mike

200m isn't that bad, but you really need to count the distance by the rout of the cable and not birds eye view.
Has it always been that speed or has it decreased since then, if that was the case then its probable down to more people getting fibre on your cabinet.

Also that Noise margin of 15.2dB is that upstream or down stream?

Paul

150m is bird, 200m is my guess at line routing. (It's pretty direct TBH)

It's pretty much always been that speed. I'm expecting it to go down as more people get added, hence the desire to track down potential line problem now.

I'm assuming the order is up/down (to be consistent with the Data Rate line), so 15.2db is, I assume, the up.

I'm also confused because all the other line stats I've seen have 0.0 for the up for Signal and Line Attentuation, and I'm wondering if that is significant.

I think the noise margin is normally between 6 and 7, but may be wrong, not yet got fibre.

I am sure somebody will jump in and correct me

Paul

If the line is running at max, which this one is on upstream, then the margin will almost certainly be above the normal 6dB.

I cannot look at mine at present - ECI modem running however it has been up at 20dB with a 19999 sync.

If running with a sub 20 sync then it will be around 6.x

You need to measure it reasonably accurately. Remember to include the drop from pole to house, 7 metres to go from underground to pole, then all of the road distance back to the primary PCP and then add on the distance from there to the FTTC twin.

Just spent the past hour on chat/phone with BT, so after going through the "script" twice, they finally did some tests from their end and said that there is a problem with the line. Have an engineer turning up on Thursday morning to figure where the problem is.

(Just recalculated measurement. No more than 270m worst case)

I am around 400m as the crow, however, I am actually at the end of a rather long loop at around 1500m.

Update:
BT came, they did a line test, said all was fine.

They went back the exchange and some checks there.

Said they were getting 80m at the cab, and it drops to 72m by the time it gets to me.

I guess I really shouldn't complain, although still not gotten an explanation why the Line and Signal attenuation are so high on such a short link.

In reply to a post by mramcha:

Update:
BT came, they did a line test, said all was fine.

They went back the exchange and some checks there.

Said they were getting 80m at the cab, and it drops to 72m by the time it gets to me.

That makes sense, it's fibre to the cab so the cab should always get 80m.

I guess I really shouldn't complain, although still not gotten an explanation why the Line and Signal attenuation are so high on such a short link.

Are they high? What values should they be exactly?

That was the title of the post!

I was trying to find out what is "normal". If there is such a thing.

My stats are this:

6. Data rate: 19999 / 71621
7. Maximum data rate: 24055 / 70937
8. Noise margin: 15.2 / 6.3
9. Line attenuation: 22.1 / 17.2
10. Signal attenuation: 22.1 / 17.2

Compared to all other examples of Line attenuation and Signal attenuation I've seen posted by others in this and other forums for the HH5, people tend to have much lower values.

I have been connected since the 16th Jan and the line has appeared stable since, yet have noticed the SNR margins getting higher. The 1st two weeks it was roughly 15.5db UP and 11.5db - 12.7db Down.

From my understanding of ADSL+2, the lower the SNR the better sync rate and throughput. I was BE member for years and could alter my IP for fast path, etc, and having a 3db SNR was great but not stable but still enabled me to sync @ a 24mb line.

With FTTC, this appears to not be the case, as I'm having more noise but the sync is the same as day 1. Not complaining as its great and i'm way happy but would like some info to why this is? I'm I the only one on the cab?


Firmware version: v0.07.03.0814-BT (Type B) Last updated 22/1/2015
4. Board version: 01
5. VDSL uptime: 1 days, 15:10:14
6. Data Rate: 20000 / 79999
7. Maximum Data Rate: 36236 / 120267
8. Noise Margin: 16.6 / 17.3
9. Line Attenuation: 0.0 / 13.8
10. Signal Attenuation: 0.0 / 0.0

@ the OP, it's possible crosstalk could be impacting your line. Still a noob with FTTC myself

Edited by deleted (Thu 19-Feb-15 18:12:00)

The line attenuation is mainly a function of line length, but in VDSL2 land there are more than 1 band plan in use, each having it's own attenuation. So the figure you see is slightly more complex than in good old ADSL terms. If you want lower attenuation you'll have to move closer to the cabinet. My line length is about 200 metres and my attenuation is around 10.

My engineer said "Oooooh you are getting 80meg at the cab".

I was like, no shirt sherlock!

The SNR on VDSL still works the same as on ADSL.

But, you are at max sync. Unless noise increases significantly or BT introduce a new product above the current 80/20 then your sync will not change.

Many people would kill for such a short / good line.

Didn't know BT had gotten to the USA

Edited by lelboy (Fri 20-Feb-15 15:02:48)

In reply to a post by mramcha:

That was the title of the post!

I was trying to find out what is "normal". If there is such a thing.

My stats are this:

6. Data rate: 19999 / 71621
7. Maximum data rate: 24055 / 70937
8. Noise margin: 15.2 / 6.3
9. Line attenuation: 22.1 / 17.2
10. Signal attenuation: 22.1 / 17.2

Compared to all other examples of Line attenuation and Signal attenuation I've seen posted by others in this and other forums for the HH5, people tend to have much lower values.

I got connected on Tuesday and a stable connection ever since. I'm about 70m from the Fibre Cab.

My Stats

Upstream line rate (kbit/s): 19999
Downstream line rate (kbit/s): 79987
Maximum upstream rate (kbit/s): 36468
Maximum downstream rate (kbit/s): 123060
Upstream noise safety coefficient (dB): 23
Downstream noise safety coefficient (dB): 18.2
Upstream interleave depth: 0
Downstream interleave depth: 0
Line standard:
VDSL
Upstream line attenuation (dB): 4.5
Downstream line attenuation (dB): 3.3
Upstream output power (dBm): -11.8
Downstream output power (dBm): 13
Channel type: None
DSL up-time: 3 days 3 hours 35 minutes 55 seconds

Why are some peoples attenuation and signal attenuation 0.0?

Not every device reports it correctly.

So I'm assuming that 0.0 is incorrect?

It looks like it's not reported rather than actually 0 which would mean "no attenuation"

Looking at Krisk's stats from page 2 it looks like his downstream attenuation is higher than mine but his max attainable is much higher than my own, is this correct or is it because his attenuation is being reported incorrectly?

It's more likely due to his line having no noise interference/crosstalk so the SNRM is massive.

Ah I see.