20MB XL Service running at about 8MB

[netutgamer]

Hi Guys

Could do with a little help, my 20MB (recently installed) internet isn't really running as I would expect it to. Everything was fine for the first 3-4 weeks, but now my speeds have dropped.

I've been checking with downloading files large files (ubuntu ISO's from the VM mirror), and also using ThinkBroadband (which according to this http://www.virginmedia.com/customers/speedtesters/ VirginMedia seem to approve of).

I've attached my results over the last few days. I don't do torrent downloading, so shouldn't be coming under speed control.

Here's the relevant data from the downstream area of my modem:

Downstream Lock : Locked
Downstream Channel Id : 4
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : 4.1 dBmV
Downstream SNR : 39.0 dB

Can anyone offer any suggestions?

I'm in Norwich, in the NR3 area connected to NTL equipment with an Ambit modem.

[Axegrinder]

What are you upstream power levels?

[netutgamer]

upstream details:

Upstream Lock : Locked
Upstream Channel ID : 2
Upstream Frequency : 22200000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 41.5 dBmV
Upstream Mini-Slot Size : 2

[moroboshi]

My 20mbit line often runs at less than 1mbit. Sadly getting Virgin to fix it has proved impossible, but at least (after weeks of badgering them) they have finally settled on two different excuses (one for the email team, one for the newsgroup team).

- Your area is over subscribed. No idea when/if it will be fixed.
- We are upgrading our network to 50mbits. No idea when/if it will be fixed.

Virgin customer service = by far the worst of any company in the UK.

[Axegrinder]

Sounds like oversubscription on your UBR to me.


Upstream levels fine btw.

[Martyn]

i get the same constantly in TN23 Area....

Downstream Lock : Locked
Downstream Channel Id : 4
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -1.5 dBmV
Downstream SNR : 39.9 dB

Upstream Lock : Locked
Upstream Channel ID : 4
Upstream Frequency : 46200000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 43.5 dBmV
Upstream Mini-Slot Size : 2

Network Access : Allowed
Maximum Downstream Data Rate : 20480000
Maximum Upstream Data Rate : 768000
Maximum Upstream Channel Burst : 1600
Maximum Number of CPEs : 1
Modem Capability : Concatenation Enabled, Fragametation Enabled, PHS Disabled

---------- Post added at 20:02 ---------- Previous post was at 19:47 ----------

Date 10/03/09 20:02:00
Speed Down 4022.03 Kbps ( 3.9 Mbps )
Speed Up 597.04 Kbps ( 0.6 Mbps )
Port 8095
Server speedtest1.thinkbroadband.com

[Peter_]

i get the same constantly in TN23 Area....

Downstream Lock : Locked
Downstream Channel Id : 4
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -1.5 dBmV
Downstream SNR : 39.9 dB

Upstream Lock : Locked
Upstream Channel ID : 4
Upstream Frequency : 46200000 Hz
Upstream Modulation : QPSK
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 43.5 dBmV
Upstream Mini-Slot Size : 2

Network Access : Allowed
Maximum Downstream Data Rate : 20480000
Maximum Upstream Data Rate : 768000
Maximum Upstream Channel Burst : 1600
Maximum Number of CPEs : 1
Modem Capability : Concatenation Enabled, Fragametation Enabled, PHS Disabled

---------- Post added at 20:02 ---------- Previous post was at 19:47 ----------

Date 10/03/09 20:02:00
Speed Down 4022.03 Kbps ( 3.9 Mbps )
Speed Up 597.04 Kbps ( 0.6 Mbps )
Port 8095
Server speedtest1.thinkbroadband.com
Your power levels are fine for EX-NTL connection so pleas try the speed test below.

-------------------------------------------------------------

If you are a Virgin Media customer then the best speedtest is from the link below.

Have you tried going to this link below to check your speeds

click on http://gamefiles.virginmedia.com/ > click on blueyonder games then go to Demos >then click on at least 2 large files and save them to your desktop, and then wait a couple of minutes then write down the transfer rates on the files that are running > times them by 8 and you will get a truer download speed.

Remember to stop and delete the files.

i.e : 250Kbps X 8 = 2Mbps, 500Kbps X 8 = 4Mbps, 1250Kbps X 8 = 10Mbps, 2500Kbps X 8 = 20Mbps
-----------------------------------------------------------

[Martyn]

im only getting about 600kbs maxium.. and it constatly going up and down in between that, no high then 600kbs tho....

[The Jackal]

Can someone check if mine look ok ? Thanks

Cable Modem Downstream
Downstream Lock : Locked
Downstream Channel Id : 1
Downstream Frequency : 339000000 Hz
Downstream Modulation : QAM256
Downstream Symbol Rate : 5360.537 Ksym/sec
Downstream Interleave Depth : taps32Increment4
Downstream Receive Power Level : -11.5 dBmV
Downstream SNR : 35.7 dB

Cable Modem Upstream
Upstream Lock : Locked
Upstream Channel ID : 2
Upstream Frequency : 34000000 Hz
Upstream Modulation : QAM16
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 44.5 dBmV
Upstream Mini-Slot Size : 2

[Turkey Machine]

That downstream power level is absolutely horrendous! Are you sure the cable's correctly screwed in to the modem?!

[Ignitionnet]

That downstream power level is absolutely horrendous! Are you sure the cable's correctly screwed in to the modem?!

It's low but it's not 'absolutely horrendous' - I've seen far worse. -11.5dBmV is workable.

The Jackal, if you are seeing reasonable performance really who cares what the power levels are, if it's not broken don't fix it :)

[The Jackal]

That downstream power level is absolutely horrendous! Are you sure the cable's correctly screwed in to the modem?!

AFAIK it is :erm:

Is it really that bad ?

---------- Post added at 22:44 ---------- Previous post was at 22:34 ----------

It's low but it's not 'absolutely horrendous' - I've seen far worse. -11.5dBmV is workable.

The Jackal, if you are seeing reasonable performance really who cares what the power levels are, if it's not broken don't fix it :)

As soon as VM replaced my trusted Old Motorola SB4100 I've had no end of problems.

I remember the guy taking it and he glanced back at me, that's when I realised my mistake. 16mbps stable connection was great now it's pants.

[Turkey Machine]

AFAIK it is :erm:

Is it really that bad ?


The only time I've ever had anything close to that (IIRC was about -8 to -9dbmv) was when I failed to screw the cable into the modem properly. Tightening the nut, a reboot later, and all was well. So check that first. :)

[The Jackal]

The only time I've ever had anything close to that (IIRC was about -8 to -9dbmv) was when I failed to screw the cable into the modem properly. Tightening the nut, a reboot later, and all was well. So check that first. :)

You do realise that this means that I'll have to get out of bed :D

I'll try it in the morning but I'm pretty much certain I haven't touched it since the tech came around besides it's hidden under the stairs - so defo will look at in the morning

[Ignitionnet]

Yep as a first course just make sure everything is done up nice and tightly mate, usually the simplest things :)

[Feenix]

Why fiddle with it if nothing is wrong? -11.5 is fine as long as the SNR doesn't drop. I've seen SACMs in the field happy as larry at -16dBmV.

Back on topic, in Norwich we've had crap speeds most of the weekend due to some network issue over in Peteborough which was fixed about 6ish on Sunday. Lots of packet loss and huge pings.

https://www.cableforum.co.uk/images/local/2009/03/51.png (http://www.speedtest.net) Mine a couple of minutes ago, NR3 Norwich

https://www.cableforum.co.uk/images/local/2009/03/52.png (http://www.speedtest.net) Sunday :(