Are my VM signal levels right?

[G77]

i never noticed anything when they did mine, same ip, happened overnight, all devices came back on. went well.

not looked at it yet but think that the modem mode lets you change the mac and get a fresh ip. i suppose its handy to have.

dyndns autoupdater would be nice to see in there but i guess, in hub mode, you dont change the wan mac and/or modem mac so why need dyndns updater?

we have kinda dynamic ip's which (hardly ever) change

[TheCoder]

Originally Posted by nibblitz

Thanks for that. So ummm, if I did whack on an attenuator to bring the upstream power down a bit would that not then knock my downstream power outside optimum levels?

No, upstream is the power level your modem needs to send back to VM so the higher the value the harder the modem is having to work. An attenuator would make it even higher. Ideally, you need a level of around 40-45dBmV but the modems will generally work fine upto around 56dBmV (they'll actually go to 58dBmV but you need some reserve for fluctuations caused by changing enviromental conditions).

The levels you have there should be fine (yes, upstream is a little high but an engineer is unlikely to be interested until its higher than 55dBmV consistantly or lots of problams - usually accompanied by lots of T4 errors in the modem log).

Your SNR actually looks pretty good so your downstream is almost spot-on.

[jet]

A little on what happened to me,
Was getting random drop-outs with internet connection, had noticed it more on nzbs and torrents where speed would look like a wave pattern because of loosing connectivity.
Vm eng came out (i had the usual mad rush to hide various equipment, lol)
levels @ s hub -12dBmV and 32dB snr Donwnstream
58dBmV upsteam
He went to green cab and took the line off that mine was split with so i had direct feed, power levels went to -8dBmV
Then got booked in to have a powered HDU fitted and remove splitter and old grey surge protector thingamabob.
After HDU Levels now are -1dBmV 38dB down
and 32dBmV up
Edit: According to this my upstream is low now but i think the HDU adds +4dB

[TheCoder]

Originally Posted by jet

After HDU Levels now are -1dBmV 38dB down
and 32dBmV up
Edit: According to this my upstream is low now but i think the HDU adds +4dB

As i mentioned in my previous post, the lower the upstream value the better - it indicates that the modem is being heard by the UBR using minimal power.

The 38dB (i presume thats your snr) is much better than the 32dB you had previously indicating reception is now fine with good differentiation between signal level and noise level. I'm actuall suprised the modem functionad at all when it was getting a -12dBmV signal - very borderline. The previous upload of 58dBmV was also very borderline and means your modem was cranked up to give maximum output power. This will likely of continuously dropped packets and even totally lost connection as the line conditions naturally worsened (yes, even VM cable is affected by the weather).

[nibblitz]

Well, in my case I think Ive solved it... I'd been seeing other peoples forum postings showing more than 1 downstream channel locked, I noticed my connection only showed 1 downstream channel locked, I just always assumed 1 downstream & 1 upstream was normal. So I replaced the lead from the splitter to the router with a thicker stiffer lead with a thicker core (I was using a thin flexible easy to hide black lead before) With the thicker lead the router is now getting 4 download channels locked, and its not playing up anymore when I get busy on my connection.. Downstream power is improved I think, its showing -3, -1.8, -2 and -2.3 on the 4 locked channels..

So, am I right in assuming that for a connection to work properly its meant to have more than 1 downstream channel?

[G77]

never noticed that before.. yeah, i'm locked to four chans

thats pretty nifty really. this docsis 3 is a bit of alright isn't it

this was the first test i did so im pretty happy with it..



im not capping any devices but not downloading anything either.

i had a torrent coming in at 2.3mb a sec last night and i've downloaded a 35gb file and its not dropped out once.

still not felt the need to go to modem mode yet

[TheCoder]

Originally Posted by nibblitz

So, am I right in assuming that for a connection to work properly its meant to have more than 1 downstream channel?

Thats the DOCSIS3 channel bonding scheme in operation. Dependant on your area you should have 3 or 4 55Mbit/sec channels available for use. Note that 50Mbit/sec can actually be handled by a single channel but the modem tends to split things somewhat over multiple channels when given the opertunity.

Most area's still only use one upstream channel but the modem is capable of using four bonded upstreams (around 80Mbit/sec total upstream).

Note that the 220Mbit/80Mbit bandwidth total is split between all users on your particular node (neighbours). The line can really only support 4 50meg users running flat out at any one time before the users impact each other.

If you examine the modem settings a little deeper you may notice the traffic burst rates. This tends to be around 10k/8k and is the maximum amount of data you can transfer before having to relinquish the line to another user. If there are no other users you get the line back for the next slot but if there are other users then you get queued to await your turn. This is why the line appears slow during busy periods - its not always capping as such but contention. Having 3/4 seperate channels can alleviate this contention problem somewhat

[jet]

From vm support:

"I'm happy to announce that we'll be releasing the R30 firmware for the Virgin Media Super Hub later today. Once it's available (approximately 6pm) you'll be able to update your Super Hub by simply turning it off at the socket for 60 seconds then back on again. Remember it may take a while for your Super Hub to download the new firmware and come back online.

Our R30 firmware includes the following changes:

Adds the Modem Mode feature.
Incorporates fixes for lock-ups (where the Super Hub appears unresponsive to traffic and the admin pages are unavailable) and reloads (where the Super Hub would reload for no apparent reason) while under heavy load in 2.4 and 5 GHz wireless modes. These symptoms were caused by a memory leak in the 2.4GHz and 5GHz wireless driver. As part of these fixes we've changed the number of channels available under 5GHz to 4.

Note: 5GHz performance can vary as although it handles interference from other wireless routers better than 2.4GHz it's ability to penetrate walls, doors etc is less. We also recommend you site your Super Hub away from central heating radiators, foil backed wall board and plasma screen TVs if you're using wireless, as these items have been known to cause issues leading to poor wireless performance. "

[G77]

wicked. r30 for everyone.