Line errors

[Tacitus]

Hi all:

Can someone interpret these figures for me:

near-end FEC error fast:   0
near-end FEC error interleaved: 536
near-end CRC error fast:   0
near-end CRC error interleaved:   1
near-end HEC error fast:   0
near-end HEC error interleaved:   0
far-end FEC error fast:   0
far-end FEC error interleaved: 136
far-end CRC error fast:   0
far-end CRC error interleaved:   5
far-end HEC error fast:   0
far-end HEC error interleaved: 272

Are these indicative of a particularly noisy line or is this pretty normal?

These are some of the line stats:

noise margin upstream: 20 db
output power downstream: 16 db
attenuation upstream: 31 db
tone   0- 31: 00 00 00 04 44 56 66 67 76 77 77 66 66 66 65 00
tone  32- 63: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone  64- 95: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone  96-127: 00 00 00 b9 bb ed fd 1d ff fe fe ff 20 30 1e ed
tone 128-159: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

noise margin downstream: 11 db
output power upstream: 11 db
attenuation downstream: 56 db
tone   0- 31: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone  32- 63: 00 00 00 78 88 77 77 07 88 88 88 88 88 88 99 99
tone  64- 95: 09 98 88 87 78 88 88 88 88 88 88 87 76 77 66 66
tone  96-127: 66 66 66 66 66 66 66 55 44 55 44 33 44 44 32 00
tone 128-159: 20 22 32 22 22 22 02 22 00 00 00 00 00 00 00 00

Seems to be the upstream tones are disapearing and it's probably this that is causing disconnects.

[Sebby]

The error count is very low, though that depends how long you've been connected. You're interleaved, so error correction is on (probably advisable on such a long line). I'm not any good at interpreting tones, but it looks like your downstream target SNRM is 12dB, probably in response to instability (unless your router sync'd at a noisy time, and now that the noise has subsided the margin has improved).

Not a lot more I can say really.

[Rik]

Seems to be the upstream tones are disapearing and it's probably this that is causing disconnects.

I'm not that hot on tones either, Tac, but as I understand it, the lower the attenuation, the more higher frequency tones can be used, hence short lines have more tones and thus have more bandwidth. You'd need to run repeated checks to see if the tones are disappearing, but my best guess is that those tones are the ones used when negotiating the sync, and nothing has changed since. There are gaps in my own tone distribution graph.

[Tacitus]

I'm not that hot on tones either, Tac, but as I understand it, the lower the attenuation, the more higher frequency tones can be used, hence short lines have more tones and thus have more bandwidth. You'd need to run repeated checks to see if the tones are disappearing,.....

Pretty much sums up my own thoughts.  Unfortunately I can only do 'snapshots' of what's going on via telnet commands, so unless I hit a noisy patch it's not really giving me a lot of information.  The upstream higher tones are, at times, non-existent and that's when it seems to drop sync.  Sync is creeping higher, having been down to the 1300 region, but I think this is as good as it gets as I've only had one disconnect so far today.

Thanks for the help.

Oh the joys of broadband in a rural area.... 

[Rik]

That might actually be useful, Tac. If the upstream is triggering resyncs it's highly unusual and limited to relatively few tones. That might enable BT to track the cause.

[Tacitus]

That might actually be useful, Tac. If the upstream is triggering resyncs it's highly unusual and limited to relatively few tones. That might enable BT to track the cause.

Actually the downstream tones look quite good at the moment.  If BT were working with iDNet I might agree Rik.   Also, I could at least talk to someone who knows what they are doing, could see it from their end and discuss it.    However, try explaining all this to Bangalore and see how far it gets you.....

Even if iDNet were unable to do anything about it as the lines are simply poor, they could at least give me some idea of what's going on. 

[Rik]

I know, it's easy to forget we can deal with issues like this, Tac.