Another "please help me with the modem readings, I've got 1mb instead of 50mb" thread

[cllp1975]

Hi All,
I won't bore you with my story, because it seems to echo just about every 50meg story on this site. But sufficed to say, that my current download is 1mb wired, and my upload is .09.... and my wifi, despite being on a vacant channel, has a radius of about 5 feet. Can you take a look at my modem readings before the engineer tries to fob me off tomorrow please? Generally, after rebooting everything, I get 40ish for about 20 minutes, and then it just goes down and down and down and then drops out....

Thanks in advance, I'm insanely grateful.... :angel:


Item Status Comments
Acquired Downstream Channel 298.751221 MHz Primary Downstream Locked
Ranged Upstream Channel 46.200001 MHz Success
Provisioning State OK Operational
Ethernet Link Status Up 100 Mbps/Half duplex

Cable Modem Downstream
DS-1 DS-2 DS-3 DS-4
Frequency 298750000 306750000 314750000 N/A
Lock Status
(QAM Lock/FEC Sync/MPEG Lock) Y/Y/Y Y/Y/Y Y/Y/Y N/N/N
Channel Id 51 52 53 N/A
Modulation 256QAM 256QAM 256QAM N/A
Symbol Rate
(Msym/sec) 6.952 6.952 6.952 N/A
Interleave Depth I=12
J=17 I=12
J=17 I=12
J=17 N/A
Power Level
(dBmV) 7.83 7.38 6.22 N/A
RxMER
(dB) 35.97 36.84 36.17 N/A
Correctable
Codewords 3820 1724 1394 N/A
Uncorrectable
Codewords 337 334 403 N/A

Cable Modem Upstream
US-1 US-2 US-3 US-4
Channel Type 1.0 N/A N/A N/A
Channel ID 4 N/A N/A N/A
Frequency
(Hz) 46200000 N/A N/A N/A
Ranging Status Success N/A N/A N/A
Modulation 16QAM N/A N/A N/A
Symbol Rate
(KSym/sec) 2560 N/A N/A N/A
Mini-Slot Size 2 N/A N/A N/A
Power Level
(dBmV) 55.50 N/A N/A N/A
T1 Timeouts 0
T2 Timeouts 0 0 0 0
T3 Timeouts 3 0 0 0
T4 Timeouts 0 0 0 0

Cable Modem Upstream Burst



US-1


Req


Init Maint


Per Maint


Short Data


Long Data


(1)


(3)


(4)


(5)


(6)
Modulation Type QPSK QPSK QPSK 16QAM 16QAM
Differential Encoding OFF OFF OFF OFF OFF
Preamble Length 36 100 100 128 128
Preamble Value Offset 244 6 6 504 504
FEC Error Correction (T) 0 5 5 4 9
FEC Codeword Information Bytes (k) 16 34 34 76 232
Maximum Burst Size 0 0 0 7 0
Guard Time Size 22 48 48 22 22
Last Codeword Length FIX FIX FIX SHORT SHORT
Scrambler on/off ON ON ON ON ON

General Configuration
Network Access : Allowed
Maximum Number of CPEs : 1
Baseline Privacy : Enabled
DOCSIS Mode : DOCSIS 3.0

Primary Downstream Service Flow
SFID : 6834
Max Traffic Rate : 53000000 bps
Max Traffic Burst : 3044 bytes
Min Traffic Rate : 0 bps
Primary Upstream Service Flow
SFID : 6833
Max Traffic Rate : 1750000 bps
Max Traffic Burst : 3044 bytes
Min Traffic Rate : 0 bps
Max Concatenated Burst : 1522 bytes
Scheduling Type : Best Effort

[Sephiroth]

I'm far from the expert on this sort of diagnosis but it seems to me that there is a high downstream power level for a not too brilliant SNR. In other words, somethings not right between you and the other end.

A good power level will hover around the 0 mark - yours at 7+. Your SNR is around 10x worse than what's considered ideal.

What do others think?

[cllp1975]

Thanks so much. I note I'm only on half duplex... that's not right is it?

---------- Post added at 22:40 ---------- Previous post was at 22:33 ----------

Thanks so much. I note I'm only on half duplex... that's not right is it?

[Sephiroth]

Well, you're right. You should set everything to auto-negotiate. Half duplex will be problematical nothwithstanding any other issues.

[cllp1975]

Thanks so much. I note I'm only on half duplex... that's not right is it?

[broadbandking]

Try setting it to auto the levels look okay for downstream as I think it can handle upto 12db not too sure tho broadbandings or moldova are your best bet

[cllp1975]

Thanks so much. I note I'm only on half duplex... that's not right is it?

[Peter_]

Thanks so much. I note I'm only on half duplex... that's not right is it?
Set it to Full Duplex


The power levels are within operational parameters but lets see what the engineer has to say about it.

[cllp1975]

Thanks for this, all. Excuse the duplicate post - was caused by the fact that I'm currently getting 1.2 down and 0.01 up!

I meant that the modem is set at half duplex - my pc adaptor is set at full duplex, as advised by telephone tech support.

Should the modem not be full duplex? Half duplex means one way traffic doesn't it?

[Sephiroth]

So, what's the router and what are the WAN settings on the router?

[cllp1975]

It's the new D-Link DIR-615. I've already had a Netgear DWR2000, which was replaced on Saturday in the hope that it was the problem. Details should be attached to this post. Using WPA2-AES on advice.

[Sephiroth]

What I need to additionally see are the following:

1 SETUP --> Internet Setup

2 SETUP --> LAN Setup

3 ADVANCED --> Advanced Network

4 MAINTENANCE --> DYNAMIC DNS

5 MAINTENANCE --> System Check (with usual users connected)

6 STATUS --> Device Information

It seems a lot, but this info is what we would use if it were our own situation to resolve.

Cheers

[cllp1975]

No probs.

Only info on "Internet setup" is my MAC, which I've tried both cloned and uncloned and the MTU of 1500.

LAN Set Up:
outer Settings
Use this section to configure the internal network settings of your router. The IP address that is configured here is the IP address that you use to access the Web-based management interface. If you change the IP address here, you may need to adjust your PC's network settings to access the network again.

Router IP Address 192.168.0.1
Default Subnet Mask : 255.255.255.0
Local Domain Name :
Enable DNS Relay : on
DHCP Server Settings
Use this section to configure the built-in DHCP server to assign IP address to the computers on your network.

Enable DHCP Server : on
DHCP IP Address Range : 0 to 199 (addresses within the LAN subnet)
DHCP Lease Time : 10080 (minutes)



Enable UPnP : on

Enable WAN Ping Respose : on
WAN PORT SPEED: 100mhz
MULTICAST STREAMS
Enable Multicast Streams : on
Wireless Enhance Mode : on

DynDNS not currently active (haven't done it yet - didn't seem much point!)


LAN
MAC Address : xxxxxxxxxxxxxxxxxxxxx
IP Address : 192.168.0.1
Subnet Mask : 255.255.255.0
DHCP Server : Enabled
Internet
MAC Address : xxxxxxxxxxxxxx
Connection : DHCP client

IP Address :
xxxxxxxxxxxxxxx
Subnet Mask :
255.255.255.0
Default Gateway :
xxxxxxxxxxxxxx
DNS :
194.168.4.100 194.168.8.100
Wireless 802.11n
SSID : xxxxxxxxxxxxxxx
Channel : 3
Encryption : AES

[cllp1975]

After a 3 and a half hour sterling effort from two fine VM dudes, they traced the problem all the way back to the cabinet. Network are due in the morning. Thanks for your help everyone. I'll keep you posted.

Keep plugging away, anyone in the same boat.... they'll take you seriously eventually!!

Props to the Twitter team too....

[Sephiroth]

I shouldn't boast - but post #2 got it right. The rest was the usual dead end.

Let us know what happens.

[cllp1975]

Well, it's a two pronged problem.... true enough, as predicted, there was significant noise on the line, not just at our cabinet, but on the master cabinet for the neighbourhood..... this has been fixed and the connection seems a lot more stable.

However, we are losing a total of 23db betweeen the cabinet and the modem, so we're getting a new drop cable and a full reinstall. The saga continues....

[cllp1975]

THE SAGA CONTINUES :bigcry:

So, Mr Tech Support came round today. I wasn't in when he called, so he made a start - replacing the cable from the cabinet to the drop, all the way up to the house.

After I got back, he borrowed my modem to make sure the speed from the cabinet was staying constant. And low and behold, within 30 minutes, it had gone from 48 to 23 to 15.

So the new drop cable was a red herring, and they're running out of ideas.... tomorrow, they're coming round to run a test on a different drop, to eliminate there being some kind of problem with my ACCOUNT settings, which is the only other thing they haven't tried. Failing that, it's off to the exchange at Lewisham to move the whole street onto a different DOCSIS to see if that helps.

One of the current theories that is floating around (basically a collection of straws, being clutched at, in much the same way as a child clutches at the big pile of straws in McDonalds in anticipation of a chocolate milkshake) is that someone, who should be on ntl:Telewest business and... well... isn't, is running a server farm in the area....

But it could still be a faulty cable they haven't found yet of course....

More news tomorrow..... if I can get online.....

[cllp1975]

Still no resolution - our connection (internet and V+ return) has been popping in and out all day, so I suspect that they've been fiddling down at the Lewisham Headend but at the end of it all, I'm still getting 9meg.

Could one of you lovely people answer me this? Here is the status page from router config:

Cable Modem Status
Item Status Comments
Acquired Downstream Channel 298.751221 MHz Primary Downstream Locked
Ranged Upstream Channel 42.799999 MHz Success
Provisioning State OK Operational
Ethernet Link Status Up 100 Mbps/Half duplex

Now surely, the Ethernet Link Status should be FULL duplex.... right? I first pointed this out to an engineer over a week ago....

[Feenix]

What has changed (signal level/SNR(RxMER)) wise since the new drop has been installed?

Have you tried your Apple directly connected to the modem with an ethernet lead?

If not do so and monitor, it could be a duff router.
If it is the same, keep an eye on your SNR (RxMER) and Power Level in the modem diagnostics.

btw half duplex of 100 meg is still 50 meg(ish/duplex) so don't worry too much about that at this stage, as above, directly connect to the modem.

[Sephiroth]

Still no resolution - our connection (internet and V+ return) has been popping in and out all day, so I suspect that they've been fiddling down at the Lewisham Headend but at the end of it all, I'm still getting 9meg.

Could one of you lovely people answer me this? Here is the status page from router config:

Cable Modem Status
Item Status Comments
Acquired Downstream Channel 298.751221 MHz
Primary Downstream Locked
Ranged Upstream Channel 42.799999 MHz Success
Provisioning State OK Operational
Ethernet Link Status Up 100 Mbps/Half duplex

Now surely, the Ethernet Link Status should be FULL duplex.... right? I first pointed this out to an engineer over a week ago....
Ah - there's a clue. If the cable modem ethernet port operates half duplex, then the router port neeeds to be half duplex otherwise there will be packet collisions, seriously degrading performance.

So there's a setting to try; also if you connect your PC directly to the modem, you need to take care of the half duplex there too.

Others may know whether half-duplex is the norm for a cable modem. The Google wisdom seems to say it is.

[Peter_]

Ethernet Link Status Up 100 Mbps/Half duplex

Now surely, the Ethernet Link Status should be FULL duplex.... right? I first pointed this out to an engineer over a week ago....
That needs to be 100Mbps/Full Duplex on 50Mb to get full utilisation.

[Sephiroth]

Hi Clip

I set up the below linked thread to establish what the half-duplex situation could mean.

http://www.cableforum.co.uk/board/12/33656200-is-vm-cable-broadband-half-duplex.html

The great and knowledgable BB made it quite clear the (despite the ambiguity out there on Googled topic) the cable modem works happily with full-duplex.

So, for it to read half-duplex in your status suggests that the other half of the ehternet link is set to half-duplex.

Let us know further please.

[cllp1975]

Thanks for this - I watched the other thread unfold. Following a highly skilled technical procedure (turning things off and turning them back on in the right order - excuse the techie jargon :rolleyes:) I have achieved the holy grail of full duplex.

It's made bugger all difference though!

Unfortunately, this was a sub-problem to the main one - we're still getting pathetic speeds (9 just now, plugged straight into the modem) and it's the same with the modem plugged straight into the street cabinet.

No movement today, so we can be fairly sure none tomorrow either. We're about to hit week 3, and Virgin are going to have to hire me a night with that bird out of Chuck as compensation if this goes on much longer.

Hope the missus doesn't read that....

Thanks so much for investigating for me - needed sorting or the main problem would never be resolved.... I really appreciate it.

[Sephiroth]

You mention the street cabinet. I was in London today, walking past three street boxes in Sidmouth Road (NW6) - one of them a biggie. Two of the boxes had been busted open with wires showing - though not yet fully all over the place. That's another buggeration potential.

Anyway, you're quite right; we have to eliminate the in-house issues first and thebn what's left is the up-hill struggle with VM.

Best of luck.

[cllp1975]

Supposedly, Networks have tidied the street cabinet and the neighbourhood feeder cabinet, and are now fiddling with the headend at Lewisham.

More news on Monday. Thanks again!

[faisalabadi]

my speeds slowed down also

[Ignitionnet]

my speeds slowed down also

I have my doubts that someone in Burnley will be affected by a street cabinet and network work in Lewisham.

[faisalabadi]

ok

---------- Post added at 12:22 ---------- Previous post was at 12:17 ----------

https://www.cableforum.co.uk/images/local/2009/10/71.png (http://www.speedtest.net)

[cllp1975]

Aaaaaand the story goes on.
Two days running, I had a guy from Networks here for 4 hours each, trying to work out the problem.

We managed to get a wired connection averaging around 47meg (yaaaay!) plugged straight into the modem.

But one problem.... the modem seems very reluctant to release the MAC - it often took 20-25 minutes before it would release it - no matter how many reboots.

And then here's the weird thing. The moment a router gets involved -and I mean ANY router - we tried 4 different models - even with only one computer, wired, the rate drops by half - 26meg was the highest we got.

And as for wireless - forget it - on any channel. It drops and doesn't get above about 10meg when it's up. One computer doesn't even want to connect to it at all.

So.... we're still struggling. Virgin haven't been in touch for 2 days, save for telling me that I have "the patience of a saint". And I'm out of ideas. And it looks like they are too....

Anyone????

[Sephiroth]

Out on a limb here - Wireshark software might tell you what's going on between the router and the modem. You have to think about what you've captured because it's end to end. I'm think hot here you could disconnect the modem and see what unusual chatter there is between router and modem. Way out but when everything else has been tried ...