Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[spudgun]

Good morning :-)

I had G.Inp applied overnight and one thing that I have noticed is that the target signal to noise margin now seems to be 6.5 rather than 6 and I wonder if anyone else had noticed something similar?

Previously, my max attainable and connection speed were pretty much the same of 73.5MB with the signal to noise margin being between 5.9 and 6.2 (fluctuating over a 34 hour period).

With G.Inp the max attainable is now 78.5, but the connection speed is 76.6 and the signal to noise margin being 6.5.

A resync produces exactly the same speeds/signal to noise margin, so I am wondering if the new target is 6.5 rather than the old target of 6?

This was all on my Zyxel 8934 on the latest firmware and I didn't have chance to test other hardware before I left for work this morning.

Has anyone else noticed anything similar?

[jid]

The SNR margin has gone up as the overheads caused by interleaving being turned off have been removed.

The Target is still 6dB, but as the overheads are less, you've the spare SNR. I went to G.INP yesterday, and my snr went from around 6dB to 6.6dB with a higher sync speed.

I'd see how your line settles over the next few days and don't keep resyncing

[Dray]

G.Inp should allow the target margin to be lowered, to 3dB say. This is one way the 100Mbps headline speed will be achieved.

[jid]

G.Inp should allow the target margin to be lowered, to 3dB say. This is one way the 100Mbps headline speed will be achieved.

In due course yes hopefully along with Vectoring this will be made possible

[spudgun]

The SNR margin has gone up as the overheads caused by interleaving being turned off have been removed.

The Target is still 6dB, but as the overheads are less, you've the spare SNR. I went to G.INP yesterday, and my snr went from around 6dB to 6.6dB with a higher sync speed.

I'd see how your line settles over the next few days and don't keep resyncing

Thanks for the most speedy and informative reply. :-)

I've got my units mixed up, so please forgive me for that. As a result of this, I don't have any spare SNR margin as I haven't hit the max of 80,000 yet

My max attainable is 78,500 and my current connection is 76,500. The connection doesn't seem to want to use the remaining .5 or SNR that I have above 6

Will see how it settles over a few days and may try the unlocked 612 that I have later on.

Thanks again

[jid]

The SNR margin has gone up as the overheads caused by interleaving being turned off have been removed.

The Target is still 6dB, but as the overheads are less, you've the spare SNR. I went to G.INP yesterday, and my snr went from around 6dB to 6.6dB with a higher sync speed.

I'd see how your line settles over the next few days and don't keep resyncing

Thanks for the most speedy and informative reply. :-)

I've got my units mixed up, so please forgive me for that. As a result of this, I don't have any spare SNR margin as I haven't hit the max of 80,000 yet

My max attainable is 78,500 and my current connection is 76,500. The connection doesn't seem to want to use the remaining .5 or SNR that I have above 6

Will see how it settles over a few days and may try the unlocked 612 that I have later on.

Thanks again

What have you mixed up? Whats your current SNR margin now?

[spudgun]

Stats (from memory) from when I left home this morning

Connection 76,500
Max attainable 78,500
Signal to Noise Margin 6.5

Previously, before G.Inp it would be something like

Connection 73,500
Max attainable 73,500
Signal to Noise Margin 6

[jid]

Stats (from memory) from when I left home this morning

Connection 76,500
Max attainable 78,500
Signal to Noise Margin 6.5

Previously, before G.Inp it would be something like

Connection 73,500
Max attainable 73,500
Signal to Noise Margin 6

These are looking pretty good

Mines at 79,999 with 6.6dB Snr, so there may be a higher level of G.inp applied to your line. But bare in mind the max attainable is a guess by your modem as what the connection speed would be in optimal/perfect line conditions - which no one can ever have

[boost]

I wonder if that extra 0.5dB is earmarked for the second bearer, should it need it? Is everyone else showing a higher target?

[Dray]

More likely that BT's TR069 system hasn't realised there's extra bandwidth available yet - assuming it's Infinity.

[WWWombat]

I don't image TR069 has anything to do with something as basic as the sync choices made by the modems.

It is obvious that, once synched, the modem calculates a "max attainable" speed as though that extra 0.5dB is available, so calculates something slightly higher than the current. At this stage, they are obviously acting as though 6dB is the target.

However, it looks like (for you) the modems are using a 6dB target during the sync, but then miscalculating the bit loading somewhat, and ending up with an actual margin of 6.5dB.

My guess is that the modems (unsure which end) are making the mistake at sync time, allowing for something within G.INP that isn't happening (at least, not yet). It might be a mistake, and it might be deliberate (and we just don't understand it enough yet). The current sync will allow for the (very small) bearer 1 to be carried - so perhaps the spare margin is something held back so that bearer 1 can expand if necessary.

Perhaps it is something used by SRA, or SOS. Does anyone know if either of these have been activated?

[WWWombat]

G.Inp should allow the target margin to be lowered, to 3dB say. This is one way the 100Mbps headline speed will be achieved.

Eircom introduced vectoring and G.INP last year, and increased the headline package speed to 100Mbps. However, they kept their target margin at 9dB.

IIRC, they also defaulted to having FEC+interleaving turned on for everyone before G.INP (though less harshly than BT's default DLM intervention level), and I think they defaulted to G.INP being active for everyone afterwards.

[AArdvark]

Perhaps it is something used by SRA, or SOS. Does anyone know if either of these have been activated?

What would SRA look like as I have it enabled on my Zyxel 8324 and cannot tell if it is being used or not ?

Would you see the Sync moving up and down ?

[WWWombat]

I imagine that you'd see SRA do relatively slow changes to sync speed, as SNR altered - with perhaps a reduction in bitswaps.

SOS would, I guess, respond to drastic SNRM changes with drastic speed changes.

[tommy45]

Last night my connection saw an improvement in SNR margins and attainable rates  this as well as very low bit-swapping for the 2hr 45mins that it lasted  my ds increased by 0.6 up 0.3db  but the attainable showed over a 2mb increase
and bit swaps on the ds reduced to 1 or 2 per min  as opposed to the average of 30 per min, maybe a disturber pair  lost sync?