Will G.Inp be enabled on my line?

Hi ,
Last week I was connected to a newly installed Huawei Cab, (I'm using a Billion 8800axl) and initially got a attainable rate of >105Mbps, with a correspondingly high SNR, however as more people have been connected to the cabinet my SNR has dropped and my Max attainable is hovering just above 80Mbps. At this rate I'll be down to 60Mbps by next week!.
I'm currently on Fast Path and the modem stats show that G.Inp is not enabled yet. My question is, when the Cabinet is upgraded to support G.Inp will all lines (with compatible modems) utilise it immediately, or will it only be applied to a line when a certain error rate threshold has been reached, or when SNR reaches a certain level?

I had an attainable of ~83, down from an initial attainable of ~95.

With G-INP, it's back up to ~87.

I think most of us where under the impression that all Huawei cabinets where activated with G.INP...

I'm not sure on the compatibility of the 8800AXL, I remember someone having some compatibility issues over on the Plusnet forum's but not sure of the outcome on that one.

I can't see you loosing much more speed on your line, also bare in mind that the DLM might be increasing your SNR to increase stability, I would say that if the speed was to drop below 80 the SNR would start to drop to compensate!

G.INP is a replacement for interleaving, so those on Fast path usually won't see it unless the DLM thinks the error rates need some form of error correction.

Most likely cross talk has been dropping your speed as others in the same cable bundle take VDSL2 - waiting on vectoring to resolve that.

Thats interesting, I assume from that that you had fairly low error rates and were on fast path.
Which would point to the fact the G.INP has not been enabled on my cab yet.

In reply to a post by MrSaffron:

G.INP is a replacement for interleaving, so those on Fast path usually won't see it unless the DLM thinks the error rates need some form of error correction.

DLM seems very eager to intervene with G.inp. Far more eager than to interleave.

In reply to a post by mlmclaren:

I think most of us where under the impression that all Huawei cabinets where activated with G.INP...

It would be a fair guess that the problems with ECI modems has halted the G.INP rollout.

No more than a guess, mind, but the A&A reports suggest the issue has gone high in BT.

I'm not sure on the compatibility of the 8800AXL, I remember someone having some compatibility issues over on the Plusnet forum's but not sure of the outcome on that one.

I have an 8800NL with G.INP activated, working with Plusnet.

As @Ignition noted, DLM is far more eager to turn on G.INP than it was the old-style FEC/interleaving.

On an old line, I'd have 600 ES's per day (from 6,000 CRC's) which wouldn't trouble DLM. On my current line, I was getting just 60 ES's per day, but G.INP was still turned on.

that the DLM might be increasing your SNR to increase stability

It's a chicken/egg thing, but ...

On FTTC, DLM doesn't alter the target SNRM. Beyond the use of FEC/interleaving (old-style) or G.INP (combined with minimal FEC/interleaving, new-style), DLM's only other weapon is to use banding - or artificially limiting the speed.

Banding is, however, likely to cause an increase in the actual SNRM.

I think there are some technical advantages to do it this way around - probably in the way in which power settings vary, so reducing the potential for crosstalk.

In reply to a post by frogfoot1:

Thats interesting, I assume from that that you had fairly low error rates and were on fast path.
Which would point to the fact the G.INP has not been enabled on my cab yet.

I'm wondering if I'll ever see an effect. My line originally had an attainable of over 90 but gradually settled down at about 69 synch. For a while interleaving kept being put on then taken off then after BT rolled out a firmware update that stopped and I've been on fast path ever since.

If I'm on fast path then presumably G.INP is not needed but equally I wonder what happened to the interference that was affecting my line at first. I seem to recall that the firmware update enabled some bit swapping but don't remember. It's just possible there's a couple more Mb/s that G.INP could give me access to. Not that it would make the slightest difference but it's interesting.

Edited by Andrue (Wed 22-Apr-15 11:34:25)

That may well be the case

Keeping errors down and thus eventually less re-syncs will be the key to ensuring people don't moan about over 2 minute resyncs when vectoring appears.

In reply to a post by Andrue:

If I'm on fast path then presumably G.INP is not needed but equally I wonder what happened to the interference that was affecting my line at first.

I have never had interleaving on my home connection and have had long, stable connection times. Attainable rate and sync dropped as crosstalk increased. I now have G.INP and am synced at 80000/20000 from the most recent pre-G.INP rate of about 75000/20000.