Why do Upstream power levels rise ??

[Telford240]

Just so I understand, just had problem with mine that was fixed last week and been on a steady upstream level of 42 last 4 days, come on tonight and up to 50, why do this happen, can someone explain, starting to panic im going to go over 55 again and start to have problems again

[General Maximus]

same probs here dude. I had an upstream problem which was causing my connection to drop a couple of weeks ago and I have now got the same problem again tonight. The only bit of good news is that I rang tech support and they said they were already aware of the issue. The bad news is that I can't get onto the service status page on the VM website to see what it says, it isn't loading for some reason so i dont know whether the problem is more widespread than just my area

[Telford240]

Just hope it doesnt go any higher, cant cope with this again, took 4 engineers to sort it already and a email to ceo

[General Maximus]

wasnt too bad for me. The muppets in the call center said my modem was faulty so i had to wait 3 days for an engineer to come round but once he got here he made a phone call and it was fixed in about 4 hours

[jb66]

Noise on the network

---------- Post added at 22:01 ---------- Previous post was at 21:59 ----------

wasnt too bad for me. The muppets in the call center said my modem was faulty so i had to wait 3 days for an engineer to come round but once he got here he made a phone call and it was fixed in about 4 hours

Your fault was passed to a network technician who had 4 hours to respond. The amp was probably tweaked

---------- Post added at 22:02 ---------- Previous post was at 22:01 ----------

wasnt too bad for me. The muppets in the call center said my modem was faulty so i had to wait 3 days for an engineer to come round but once he got here he made a phone call and it was fixed in about 4 hours

Your fault was passed to a network technician who had 4 hours to respond. The amp was probably tweaked

[nodrogd]

Just had to have a tech visit to tweak my upstream. During the recent hot weather went right up to 62 and knocked out both the internet and on-demand on V boxes for 2 days. Soon as the temperature dropped everything started coming back. Doesn't help that I'm right next to the street cab.

[RedDragon]

The problem is the street amps are effected by hot weather, usually losing a few dB, however your return path should have enough head room to take this into account, jumping from 42 to over 60 would indicate a problem with the amp, assuming there is no fault between the amp and your modem. Networks would be able to check on the system if other customers fed from that amp were also dropping off.

[Sephiroth]

Igni will be quick to correct me, but downstream issues can also affect upstream power levels, I'd have thought.

If you're seeing the modem stepping through to the high levels, then if a downstream impairment prevents the keep-alives from working, the modem US power steps up to try and drive a respnse through to the CMTS. At that stage, the CMTS doesn't know why it is not receiveing the keep-alive response.

Something like that.

[Ignitionnet]

Haha.

As you know from your PM I just happened to be here, I'm not stalking :p:

Those ramp ups only happen during initial ranging. Once the modem is online it will only adjust transmit power when directed.

If a modem suddenly goes high it's because it's been told to by the CMTS at Virgin. This is usually caused by a sudden increase in attenuation causing a low receive power at the CMTS, which can be caused by a number of things, faulty cabling, amplifiers going wrong, connectors coming loose, laser or fibre problems, etc, etc.

Extreme downstream impediments cause T4s as the modems don't see their unicast maintenance opportunity or its' retransmits. The only time modems try and 'drive' something to the CMTS is at initial ranging when they increment transmit power by 3dBmV steps until they receive an initial ranging response from the CMTS with a power adjustment.

Another thing to bear in mind is that modems only respond when told to do so, and they are told to do so in the upstream MAP, where they are given a slot to transmit their maintenance request. If they don't get any response back from the CMTS they have to wait for another maintenance period.

[General Maximus]

I am so glad you explained all that because although my connection is fine atm, I am still getting T3 and T4 timeouts (currently 6 a piece) and this keeps popping up a coule of times a day in my modem log

No Ranging Response received - T3 time-out;CM- (deleted mac addresses)