20mbps Virgin cable - stability and tech support

ex-marine · 08-05-2008, 21:03

Hi,
I'm attempting to help a virgin BB user in Leeds. High level symptoms are: dropped packets leading to timed out web sessions, inability to mail and therefore an un-useable connection.

Techs:
Modem details
Information

Cable Modem : Euro-DOCSIS 1.0/1.1/2.0 Compliant
MAC Address : 00:XXXXXXXXX:91:3D:48
Serial Number : 0014XXXXXXXX13D48
Boot Code Version : 1.1.2c
Software Version : 2.111.1001
Hardware Version : 1.9

Status

Acquire a Downstream Channel 586750000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational

Downstream

Downstream Lock : Locked
Downstream Channel Id : 7
Downstream Frequency : 586750000 Hz
Downstream Modulation : QAM64
Downstream Symbol Rate : 6952 Ksym/sec
Downstream Interleave Depth : taps12Increment17
Downstream Receive Power Level : -10.0 dBmV
Downstream SNR : 29.5 dB

Upstream

Upstream Lock : Locked
Upstream Channel ID : 3
Upstream Frequency : 42800000 Hz
Upstream Modulation : QAM16
Upstream Symbol Rate : 2560 Ksym/sec
Upstream transmit Power Level : 54.5 dBmV
Upstream Mini-Slot Size : 2

Upstream Burst

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 64 128 128 200 216
Preamble Value Offset 244 6 6 504 504
FEC Error Correction (T) 0 5 5 5 9
FEC Codeword Information Bytes (k) 16 34 34 78 232
Scrambler Seed 338 338 338 338 338
Maximum Burst Size 0 0 0 19 139
Guard Time Size 8 48 48 17 77
Last Codeword Length Fixed Fixed Fixed Short Short
Scrambler on/off On On On On On

Operation Config

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

More to follow...

---------- Post added at 19:53 ---------- Previous post was at 19:51 ----------

Modem Error Log

First TimeLast TimePriorityDescription
Thu May 08 15:57:22 2008 Thu May 08 15:57:22 2008 Information (7)The s/w filename specified in the config file is the same as ...
Thu May 08 15:57:22 2008 Thu May 08 15:57:22 2008 Information (7)A software upgrade filename was specified in the config file.
Thu May 08 15:57:22 2008 Thu May 08 15:57:22 2008 Information (7)Authorized
Thu May 08 15:57:22 2008 Thu May 08 15:57:22 2008 Information (7)Registration complete!
Thu May 08 15:57:21 2008 Thu May 08 15:57:21 2008 Information (7)We registered with a DOCSIS 1.0 config file!
Thu May 08 15:57:21 2008 Thu May 08 15:57:21 2008 Information (7)Received a REG-RSP message from the CMTS...
Thu May 08 15:57:21 2008 Thu May 08 15:57:21 2008 Information (7)Sending a REG-REQ to the CMTS...
Thu May 08 15:57:21 2008 Thu May 08 15:57:21 2008 Information (7)CableModem SNMP configure complete
Thu May 08 15:57:19 2008 Thu May 08 15:57:19 2008 Information (7)IP init completed ok
Thu May 08 15:57:19 2008 Thu May 08 15:57:19 2008 Information (7)CableModem TFTP init ok
Time Not EstablishedTime Not EstablishedError (4)ToD request sent- No Response received
Time Not EstablishedTime Not EstablishedInformation (7)CableModem DHCP client init ok
Time Not EstablishedTime Not EstablishedCritical (3)DHCP WARNING - Non-critical field invalid in response.
Time Not EstablishedTime Not EstablishedInformation (7)MAP w/initial maintenance region received
Time Not EstablishedTime Not EstablishedCritical (3)No Ranging Response received - T3 time-out
Time Not EstablishedTime Not EstablishedInformation (7)MAP w/initial maintenance region received
Time Not EstablishedTime Not EstablishedCritical (3)No Ranging Response received - T3 time-out
Time Not EstablishedTime Not EstablishedInformation (7)MAP w/initial maintenance region received
Time Not EstablishedTime Not EstablishedInformation (7)Downstream sync ok
Time Not EstablishedTime Not EstablishedInformation (7)Beginning initial ranging...
Time Not EstablishedTime Not EstablishedInformation (7)downstream time sync acquired...
Time Not EstablishedTime Not EstablishedInformation (7)Downstream sync ok
Time Not EstablishedTime Not EstablishedInformation (7)starting ds time sync acquisition...
Time Not EstablishedTime Not EstablishedInformation (7)Locked on the downstream. Waiting for UCDs...
Time Not EstablishedTime Not EstablishedInformation (7)Downstream lock ok
Time Not EstablishedTime Not EstablishedInformation (7)Sync Start
Thu May 08 11:28:42 2008 Thu May 08 11:28:42 2008 Critical (3)DHCP WARNING - Non-critical field invalid in response.
Thu May 08 08:59:33 2008 Thu May 08 08:59:33 2008 Critical (3)DHCP WARNING - Non-critical field invalid in response.
Thu May 08 08:59:17 2008 Thu May 08 08:59:17 2008 Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC f...
Thu May 08 08:59:03 2008 Thu May 08 08:59:03 2008 Critical (3)Received Response to Broadcast Maintenance Request, But no Un...
Thu May 08 08:59:22 2008 Thu May 08 08:59:22 2008 Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/Q...
Thu May 08 08:55:28 2008 Thu May 08 08:55:28 2008 Critical (3)REG RSP not received

---------- Post added at 19:57 ---------- Previous post was at 19:53 ----------

Packet Snapshots (every 10-20secs):

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN 100M/Full 100891 130549 0 1681 3018 01:58:52
LAN 100M/Full 225894 171505 0 340 488 01:58:52
WLAN 11/54/108M 16112 85 0 48 0 01:58:52

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN 100M/Full 100958 130616 0 1872 3534 01:59:12
LAN 100M/Full 225904 171528 0 446 1605 01:59:12
WLAN 11/54/108M 16171 85 0 1173 0 01:59:12

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN 100M/Full 100993 130647 0 1628 2917 01:59:22
LAN 100M/Full 225913 171543 0 340 793 01:59:22
WLAN 11/54/108M 16193 86 0 476 0 01:59:22

Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN 100M/Full 101092 130748 0 1340 3870 01:59:42
LAN 100M/Full 226009 171642 0 921 1966 01:59:42
WLAN 11/54/108M 16202 86 0 48 0 01:59:42

---------- Post added at 19:59 ---------- Previous post was at 19:57 ----------

Custom ping to Virgin peer (bbc) with 1000byte packet *100

P:\>ping -f -n 100 -l 1000 bbc.co.uk

Pinging bbc.co.uk [212.58.224.131] with 1000 bytes of data:

Reply from 212.58.224.131: bytes=1000 time=19ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=15ms TTL=118
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=19ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=20ms TTL=118
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=19ms TTL=118
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=20ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=15ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=20ms TTL=118
Request timed out.
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=20ms TTL=118
Request timed out.
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=22ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=20ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=20ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=28ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Request timed out.
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=17ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=15ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=19ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=18ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=15ms TTL=118
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Reply from 212.58.224.131: bytes=1000 time=16ms TTL=118
Reply from 212.58.224.131: bytes=1000 time=19ms TTL=118

Ping statistics for 212.58.224.131:
Packets: Sent = 100, Received = 64, Lost = 36 (36% loss),
Approximate round trip times in milli-seconds:
Minimum = 15ms, Maximum = 28ms, Average = 17ms

---------- Post added at 20:03 ---------- Previous post was at 19:59 ----------

Traceroute to BBC:

P

:\>tracert bbc.co.uk

Tracing route to bbc.co.uk [212.58.224.131]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms 192.168.1.1
2 7 ms 8 ms 7 ms 10.120.112.1
3 13 ms 15 ms 8 ms leed-t2cam1-b-ge94.inet.ntl.com [80.0.55.9]
4 10 ms 9 ms 10 ms seac-dpim1-4-coc-1-gw.service.virginmedia.net [8
0.0.50.158]
5 9 ms 10 ms 9 ms lee-bb-b-so-020-0.inet.ntl.com [213.105.175.69]

6 15 ms 15 ms 32 ms pop-bb-a-as1-0.inet.ntl.com [213.105.175.130]
7 14 ms 14 ms 17 ms pop-bb-b-ae0-0.inet.ntl.com [213.105.174.230]
8 28 ms 16 ms 23 ms tele-ic-2-as0-0.inet.ntl.com [62.253.184.6]
9 26 ms 44 ms 13 ms ntl-ge2-8.prt0.thdo.bbc.co.uk [212.58.239.217]
10 17 ms 14 ms 15 ms 212.58.238.129
11 17 ms 14 ms 25 ms rdirwww-vip.thdo.bbc.co.uk [212.58.224.131]

Trace complete.

Druchii · 08-05-2008, 21:06

Downstream Receive Power Level : -10.0 dBmV
Downstream SNR : 29.5 dB

Those figures are extremely borderline, -10 is the limit if i remember correctly. So, he/she is on it.

Downstream SNR should ideally be above 30dB as well, so they're just under. This would cause problems.

DocDutch · 08-05-2008, 21:09

do you know what modem it is? if its a NTL 100/120 (silver modem) then that could be the problem.

---------- Post added at 21:09 ---------- Previous post was at 21:08 ----------

ow

btw

you should normally be in safe hands here.

sollp · 08-05-2008, 21:09

The downstream levels are incorrect, it should be around -5dB- +5dB,(these levels are approx, and they are not the actual stated specs for this modem) the SNR should be around 33-35dB,(again not the actual stated specs for this modem). The SNR will improve when the levels are corrected, also you have copied the Downstream levels twice so can you resend the upsteam levels again.

If the person your helping can do the basics of looking at there internal installation and visualy checking the cabling to make sure its not damaged, check the connectors aren't loose. This is much as you can do, if this dosen't help then you'll need to get a visit sorted.

There is a problem with the levels, so it will need fault finding to find out where the problem is.

ex-marine · 08-05-2008, 21:09

As you can see, response times are fine (when the packets get through).
I'm attempting to support this box remotely (SSH/Logmein/Remotedesktop) which is extremely difficult as any session is terminated every few seconds. I have to paste a command, and wait to be able to log in again to see the result.

The end user has:

Logged a "support" call with Virgin
Engineer arrived today and was surprised to learn of a mystical command for checking connectivity called "ping"
Engineer assured his customer that the engineers boss would call back and would attend to help resolve later
Engineer phoned back later today to say that said boss is refusing to talk to his customer and is busy but might drop by on Monday

I have ruled out any other local devices by replacing the router, removing the switch from the equation (wired laptop plugged into single port on both old and replacement router).

I'm at the end of my tether, the end user has now ordered a redundant BT line but that may take up to a month to provision. Anything network/OS related I can do, I have no idea on telephony/broadband so I really would appreciate any ideas/pointers/bb specific investigations I can do to help resolve.

Virgin media's final statement on the matter is "There is no problem with our equipment", not even a "as far as we can tell" in sight.

Any help would be greatly appreciated.

Many thanks

moaningmags · 08-05-2008, 21:10

Not 100% sure as I'm not ex-ntl trained but

Downstream Receive Power Level : -10.0 dBmV
Downstream SNR : 29.5 dB

Power level looks too low and SNR looks low too.
Can you post the upstream as you posted downstream levels twice.

Low SNR will cause packet loss and intermittent connection.
If the levels above are below the ex-ntl limits you'll need to call tech support for an engineer visit or book it through the newsgroups.
Either way I'd suggest doing the tests again with the router removed. It rules out the router and stops a clueless agent agent blaming the router and will get a resolution quicker.
Hopefully an ex-ntl tech will be able to confirm the levels.

HTH
Mags

Wow, there weren't any replies when I started writing this.

ex-marine · 08-05-2008, 21:13

Quote:

Originally Posted by DocDutch

do you know what modem it is? if its a NTL 100/120 (silver modem) then that could be the problem.

---------- Post added at 21:09 ---------- Previous post was at 21:08 ----------

ow

btw

you should normally be in safe hands here.

Not seen it but it isn't the silver modem, it's black.

---------- Post added at 20:12 ---------- Previous post was at 20:11 ----------

Quote:

Originally Posted by moaningmags

Not 100% sure as I'm not ex-ntl trained but

Downstream Receive Power Level : -10.0 dBmV
Downstream SNR : 29.5 dB

Power level looks too low and SNR looks low too.
Can you post the upstream as you posted downstream levels twice.

Low SNR will cause packet loss and intermittent connection.
If the levels above are below the ex-ntl limits you'll need to call tech support for an engineer visit or book it through the newsgroups.
Either way I'd suggest doing the tests again with the router removed. It rules out the router and stops a clueless agent agent blaming the router and will get a resolution quicker.
Hopefully an ex-ntl tech will be able to confirm the levels.

HTH
Mags

Apologies for the duplicate down/s, trying to get the up/s now but it's very difficult as I get discon/d every few seconds. Be back with an OP update as soon as possible.

---------- Post added at 20:13 ---------- Previous post was at 20:12 ----------

Thank you all ever so much for the Welcomes and quick early responses.

DocDutch · 08-05-2008, 21:13

the 250/255 series... you know how long this has been happening? perhaps a case of modem overheating?

these are my stats on my 250

Downstream Lock : Locked Downstream Channel Id : 1 Downstream Frequency : 330750000 Hz Downstream Modulation : QAM64 Downstream Symbol Rate : 5056.941 Ksym/sec Downstream Interleave Depth : taps32Increment4 Downstream Receive Power Level : -3.5 dBmV Downstream SNR : 35.0 dB

could be a signal problem...

sollp · 08-05-2008, 21:14

Quote:

Originally Posted by ex-marine

Not seen it but it isn't the silver modem, it's black.

---------- Post added at 20:12 ---------- Previous post was at 20:11 ----------

Apologies for the duplicate down/s, trying to get the up/s now but it's very difficult as I get discon/d every few seconds. Be back with an OP update as soon as possible.

At this moment it dosen't matter what version of modem it is, the problem is a levels issue, this can be caused either in the home or in the cable network, either way you'll need a competent engineer,(well looks likes they have had the incompetent one) to fault find the problem.

Ex-Army

ex-marine · 08-05-2008, 21:19

OP updated with correct up/s

moaningmags · 08-05-2008, 21:21

Upstream power level is borderline too
You def need a proper tech.

sollp · 08-05-2008, 21:23

The upstream levels of 54dB, is the maximun levels when the upstream is QAM16, this will need lowering, now does the OP have internal splitters in the house, like a VM STB also installed as well? As this will again affect upstream and downstream levels.

Once the levels issue is sorted, the person your helping will need to find out what version modem they have, Ambit 250-256 will be fine, better with latest versions of 255/256 though, if none of these get it replaced when Tech comes to fix levels issues. Also take out the router do ping test then reintroduce the router, again perform ping test. At each stage note if your experiencing packet loss or not.

ex-marine · 08-05-2008, 21:30

No splitters, sounds like the unit may be physically too far from the nearest signal source.... thoughts?

SnoopZ · 08-05-2008, 21:30

Your upstream of 54dB is far to high and you need to get that sorted with a tech call out.

sollp · 08-05-2008, 21:44

Quote:

Originally Posted by ex-marine

No splitters, sounds like the unit may be physically too far from the nearest signal source.... thoughts?

Could be that it wasn't installed properly in the first place, and any slight drop in the network levels,(as can happen when it gets hot) will result in the service dropping off as it may have just been working ok when it was cooler,(again this is just one of many causes). Could be damage to the drop cable in the garden, this often happens at this time of year when people start gardening after the Winter time,(again another possibility). Has the person tried moving the installation at any time, done there own DIY move basically?