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[j0hn]

I changed from a HG612 to a Zyxel VMG8924 earlier, and it's now using a 3rd DS band that my line has never used before. Is this normal behaviour for a new modem?
I was also changing my DSL cable so made sure i did these both separate so I could see which of the 2 changes did what to my line.
1st off I added the new cable to my HG612. This increased my attainable from 50-52mb to 56mb. This also dropped attenuation slightly on D2 and D3.
Then i added the Zyxel, increasing my attainable again. It's currently at 60mb, and now using SNRM band D3 which my line has never used. The discovery phase hasn't changed.
My line now has a HUGE jump in FEC's and a fairly big drop in Bitswaps.

Is there anything I should be worried about or keeping an eye on? I was expecting slight changes to error rates, perhaps the attainable rate, but not the extra downstream band or swings in FEC/bitswaps.

The cable I swapped was a Belkin 1.8m DSL cable which I replaced with a cat5e cable from Mr Telephone on Ebay. Well worth the £5 odd I spent on it.

should have added, username on MDWS is minted

[skyeci]

Well you are currently on interleaving and delay. Lets hope you will move over to fastpath at some point. Might pay to leave alone now and let dlm do its thing..
Your upload sync is higher than the attainable. Perhaps this will change at some point. I get more ES per 24 hours on fastpath with zyxel but was told this was normal ...

Sorry forgot to say I tried one of those mr telephone cables but ended up with a lower sync on both ds and us.. reverted back to the zyxel supplied lead and it was higher on both sync rates..

[j0hn]

my lines always been interleaved. it reset a few weeks ago and i had fastpath for a whopping 3 days. all green everyday since and no change. really annoying part was i didn't even break mtbe limit as I only has 1382 ES over 24 hours.
Upstream attainable has dropped since I posted this thread. I usually have around 7.5mb attainable upstream, I was connected at 12mb last week after the US SNRM dropped right down.

[skyeci]

Hmm i would be inclined to revert to the zyxel lead if you have the original and when your snrm is at its peak. Perhaps with the zyxel eventually you might get fastpath back.. mr t's lead didnt seem to get in with my 8324. If you do decide to change it over wait at least 31 mins before reconnecting the modem from disconnection. Mine flipped to fast path about 4 days after starting with the 8324..

[j0hn]

What could be causing the huge swings in FEC? it coincides with steps in the downstream SNRM. Could it be caused by REIN? or possibly crosstalk, with a neighbour connecting?
the FEC count dropped at 10:22pm, then shot back up at 09:54am. The DS SNRM jumps were the exact same time.

[j0hn]

The exact same just happened again at 11:37pm
The DS SNRM just jumped up 0.4dB and the FEC rate dropped massively from around 40,000/min to around 2,000/min.
If the pattern continues then I expect the DS SNRM to drop around around 8-9am causing the FEC count to shoot back up.
If it does then I'll probably switch back to the Huawei HG612 to see if this is something new happening to my line or if it only affects the Zyxel.

[WWWombat]

It does have a feel of being noise created by another modem, being turned on & off, rather than some other disturbance. ie crosstalk. But the evidence remains light.

I suspect the errors you see are partly caused by the way the Zyxel has managed to coax 10Mbps extra (whoops: 4Mbps *) out of the line, while managing to increase the SNRM.

It suggests the chipset is better at pulling signal out of noise at 6dB, but not quite good enough when the margin drops nearer to 5dB. The chipset, essentially, is giving up some of that 10Mbps (whoops: 4Mbps *) gain in the form of increased errors in the bitstream.

Fortunately, the errors only seem to come in the form of FECs. It is too early to be totally definitive, but it doesn't seem to be having much of an impact on CRCs.

If you want to keep most of the gain in speed, but lose some of the errors, then keeping the Zyxel, but re-syncing at a time when the other noise is at its worst (ie the SNRM is at its lowest) would be beneficial.

(* - I read the wrong graph for the gain. Attainable jumped by 10Mbps; actual jumped by only 4Mbps)