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Author Topic: BT nationwide rolling out G.INP/PhyR and changes to DLM.  (Read 63158 times)

simoncraddock

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #30 on: January 11, 2015, 03:12:39 PM »

Hmm I wonder if this is why my Billion lost a large chunk of 'attainable speed' prior to Xmas?
I enabled PhyR on the DS earlier this week during the initial set up and it seemed to recoup that lost speed but I didn't associate it with this at the time.

I have been loaned another Asus DSL-68U and noticed this morning with G.INP enabled my attainable rate is roughly 85/24 and holding steady, yet with PhyR on the Billion and ZyXEL its at roughly 61/22. It makes you wonder if the Broadcomm/ECI chipsets run slightly on the cautious side by restricting the DS for stability purposes compared to the Mediatek chipset which has no restrictions.

Please quote actual sync speeds and snrm rather than just attainable thanks.

Only quoting attainable doesnt have much meaning on its own because its reliant on the coding of the firmware on that device.

Also the asus device isnt stable, so its unfair to compare it to devices that are stable.

Its not always right to go after that extra few mbit of sync speed, on my line the zyxel syncs higher than the billion, but it had a higher rate of ES, plus its buggy firmwares put me off, so I chose the billion for every day use.

Remembering stats isn't always possible, not all of us perform 24/7 monitoring so we can only quote what we remember.

However since hooking up the Asus 3.5 days ago it's been very stable, to the point DLM actually took favour and decreased interleaving yesterday for the first time in over a month which it didn't do whilst using the ZyXEL or Billion.
« Last Edit: January 11, 2015, 07:24:28 PM by simoncraddock »
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Ixel

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #31 on: January 11, 2015, 03:15:29 PM »

Hmm I wonder if this is why my Billion lost a large chunk of 'attainable speed' prior to Xmas?
I enabled PhyR on the DS earlier this week during the initial set up and it seemed to recoup that lost speed but I didn't associate it with this at the time.

I have been loaned another Asus DSL-68U and noticed this morning with G.INP enabled my attainable rate is roughly 85/24 and holding steady, yet with PhyR on the Billion and ZyXEL its at roughly 61/22. It makes you wonder if the Broadcomm/ECI chipsets run slightly on the cautious side by restricting the DS for stability purposes compared to the Mediatek chipset which has no restrictions.

Please quote actual sync speeds and snrm rather than just attainable thanks.

Only quoting attainable doesnt have much meaning on its own because its reliant on the coding of the firmware on that device.

Also the asus device isnt stable, so its unfair to compare it to devices that are stable.

Its not always right to go after that extra few mbit of sync speed, on my line the zyxel syncs higher than the billion, but it had a higher rate of ES, plus its buggy firmwares put me off, so I chose the billion for every day use.

While I agree with what you've said about the attainable rate being an unreliable comparison, I don't agree with what you've said in terms of instability. The device was considerably unstable, but as I will repeat - most of the instability was around a process called 'spectrum' which if left running in the background would for some reason cause a huge amount of CRC errors. I've not only found that since killing it that the device has been considerably better, some other people on another forum have also reported similar results.

Anyway without me dragging this off topic any further, I'll leave it there :).

EDIT: Forgot to mention, I won't deny however that the device's chipset might not be entirely as stable on long lines, but as I'm not a huge distance from the cabinet mine is working fine at the moment and I expect further improvement once G.INP is available.
« Last Edit: January 11, 2015, 03:18:23 PM by Ixel »
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Chrysalis

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #32 on: January 11, 2015, 05:45:06 PM »

yeah, my comments are also based on feedback for the device on plusnet's forums, it doesnt have a good showing on there.

If you have found something that makes it much more reliable have you suggested to asus to make those changes by default?
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Ixel

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #33 on: January 11, 2015, 05:49:39 PM »

yeah, my comments are also based on feedback for the device on plusnet's forums, it doesnt have a good showing on there.

If you have found something that makes it much more reliable have you suggested to asus to make those changes by default?

Yeah, babis3g and myself have told ASUS about this problem so they're aware it exists - when they plan to release a fix for the spectrum process I don't know though. The most recent firmwares we had from ASUS via email were 2158 betas (both with spectrum removed temporarily, but one had the new bitswap and the other had the original bitswap). I'm not entirely sure whether there's a difference between the two bitswaps, but currently I'm running the official 2158 and kill spectrum manually.
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simoncraddock

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #34 on: January 11, 2015, 07:19:28 PM »

yeah, my comments are also based on feedback for the device on plusnet's forums, it doesnt have a good showing on there.

If you have found something that makes it much more reliable have you suggested to asus to make those changes by default?

Yeah, babis3g and myself have told ASUS about this problem so they're aware it exists - when they plan to release a fix for the spectrum process I don't know though. The most recent firmwares we had from ASUS via email were 2158 betas (both with spectrum removed temporarily, but one had the new bitswap and the other had the original bitswap). I'm not entirely sure whether there's a difference between the two bitswaps, but currently I'm running the official 2158 and kill spectrum manually.

Likewise, running exactly the same firmware with spectrum killed and in 50+hrs since DLM decreased interleaving much to my surprise I've the following error stats:

CRC DS: 6
CRC US: 15
ES DS: 8
ES US: 18
SES DS: 1
SES US: 2
HEC DS: 0
HEC US: 0

What is however really surprising is that neither the Billion or ZyXEL I have can come close to such low numbers, if they are indeed correct. However with DLM reducing my interleaving level on Friday there's no reason to suggest they are inaccurate.
« Last Edit: January 11, 2015, 07:25:48 PM by simoncraddock »
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Chrysalis

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #35 on: January 11, 2015, 08:20:05 PM »

sadly they are definitely broken.

You cannot have more ES than CRC.

A ES is at least 1 CRC.

Plus to boot you also have none zero SES.

Not only does the SES to ES ratio seem weird but it also further's the point the CRC isnt right.

But good news on your stability anyway.

What is the actual sync speed and snrm? surely you can provide these figures as its in use right now.

I am curious tho if that firmware has a bug counting errors and as such is sending bad info back to the DSLAM which in effect has led to DLM been misled?
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simoncraddock

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #36 on: January 11, 2015, 08:53:35 PM »

Actual sync is 54/19 up from 52/19 earlier this week (not significant could just be purely the snrm being lower right now)
SNRM is 6.0db DS / 6.1db US
Interleaving is down to 659 from 984.

There are quite a few anomalies in the stats, FEC still being a big one.
DSLuptime is showing different to the GUI also but without wanting to rock the boat, it appears generally to be performing better than the Billion & ZyXEL regardless of these mis-counts.

In almost 5 weeks I saw no gain via DLM whilst using a Broadcomm based unit, yet 24hrs after hooking up the ASUS it reduces Interleaving by almost a third, coincidence or cumulative affect of the past month perhaps?

I've just triggered a re-sync as of 20:30 so I can check a clean batch of stats again in 24hrs. I'm wondering if the initial process of turning spectrum off disrupted the counts.

If it's working I'm happy to let it do it's job regardless of firmware inconsistencies that don't affect the performance, they will get sorted eventually just like other devices.
« Last Edit: January 11, 2015, 08:58:22 PM by simoncraddock »
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Chrysalis

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #37 on: January 11, 2015, 09:04:34 PM »

ok thanks for info.

so with a snrm of 6db its estimating an extra 30 attainable?
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simoncraddock

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #38 on: January 11, 2015, 09:13:36 PM »

Both the Billion and ZyXEL hovered around 6.4 to 6.6db from memory with attainable sitting between 60 and 62/19, I can't see any stats on MyDSLWebStats with me being offline.

I'm currently showing 81/22 on the Asus which will probably rise gradually as it has done before, which I'll be honest is odd but how can you be sure Broadcomm and ECI don't air on the cautious side and artificially reduce this for stability. I'm not going to start messing with DLM over rides like Ixel has been doing just to test stability at the upper reaches of the attainable figure as I only have access to this device for 2 more weeks and don't want DLM to kick me down for tampering. However it will be interesting to see if DLM continues to favour the current performance.
« Last Edit: January 11, 2015, 09:18:52 PM by simoncraddock »
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Chrysalis

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #39 on: January 11, 2015, 09:19:44 PM »

its odd to the point its plain wrong.

Of course it is possible both the broadcom devices are also not correct, but their estimates are much more realistic.

Plainly speaking, if you were to resync now with that estimated attainable and it was accurate then you would expect to actually get close to that sync speed.  The attainable is an estimate of what sync speed you would get if you resynced at that moment.

So the asus syncs 2-3mbit higher but also has a bit lower margin?

One of kitz recent posts gave an estimate on how much the zyxel reports for her line per db of snrm.  On a longer line where is less tones available its even lower per db.  My billion was estimating an extra 3mbit for 0.5-0.7db of spare snrm above 6db and I reckon that was an "over" estimate.

With a 6db margin given 6db is the target your attainable should be the same or extremely close to your sync speed.

Right now I am synced at 72916 with a 5.9db snrm, the attainable estimated by modem is 72892.

Ok check max's post here with pics.

http://forum.kitz.co.uk/index.php?topic=14822.msg277681#msg277681

HE has a 10db margin for just over extra 30mbit attainable, its an interleaved screenshot so the attainable is inflated.

I was going to get more info of mydslwebstats but lost the tab in firefox.
« Last Edit: January 11, 2015, 09:27:53 PM by Chrysalis »
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simoncraddock

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #40 on: January 11, 2015, 09:23:58 PM »

My actual speed started dropping off when they turned of DLM and so far hasn't recovered. Attainable as been fairly consistent on the ZyXEL however the Billion dropped to around 45/22 just before the holidays. Only earlier this week did I reconnect the Bilion to find it was back to around 61/22 attainable but still only roughly 50/19 actual.

Originally the Billion at time of purchase early November was showing around 68/23 attainable and 64/19 actual.

There are some odd things happening for sure.
« Last Edit: January 11, 2015, 09:33:29 PM by simoncraddock »
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kitz

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #41 on: January 11, 2015, 10:06:07 PM »

>> I'm currently showing 81/22

If a line is interleaved, then the max attainable sometimes goes to pot.  Its something to do with the router thinking there is 'spare' but the reality is when Interleaving and error correction is turned on, the overheads for RS encoding is actually using it for redundant data.  The ASUS isnt the only router that doesn this..  Ive seen it happen on several if not most modem/routers. 

The errors count does look a little strange I'd expect more than 6CRCs if an SES has been recorded.  A reset is perhaps a good idea :)

As regards the error rate and reduction in interleaving... in all fairness iirc you did get a bit clobbered by the DLM when you first had issues with the ASUS, so now that they appear to have fixed the f/w you are probably recovering from that.    I cant recall exactly but if you were syncing at >60 Mbps when using the Billion/Zyxel you cant compare the error rate to a router that is now syncing at 54Mbps.   With the lower speed I'd expect the errors to be substantially lower.  Hopefully the DLM will recover and you can get back up to >60Mbps again.  :fingers:

Im not interleaved & judging by what my SNRm is, then my max attainable rate seems pretty realistic.
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Chrysalis

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #42 on: January 11, 2015, 10:15:28 PM »

Kitz yeah but have you seen any other modems over estimate by such a large number? to have that estimate on a 6db margin is completely whacked.
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jid

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #43 on: January 11, 2015, 10:22:52 PM »

Kitz yeah but have you seen any other modems over estimate by such a large number? to have that estimate on a 6db margin is completely whacked.

My attainable on an 8dB margin is 84000 therabouts, and when I had a 6dB it was 83500 according to my stats  ??? On the Super Router I used to get an attainable of 90000 in the same conditions.
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Chrysalis

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Re: BT nationwide rolling out G.INP/PhyR and changes to DLM.
« Reply #44 on: January 11, 2015, 10:42:19 PM »

So basically take attainable with a pinch of salt when interleaved.
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