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[McNugget]

Posted this on the BT forums, got no response so thought i'd try here after stumbling across this forum on google,

I've been playing a lot of MW3 lately and i've noticed an interesting trend,
 
Now i think it's safe to say that MW3 has a detailed history of lag comp messing up people who have fast connections, something which always affects me.
 
My modem syncs at 80Mbps down and 20up, and from the modem statistics i am on fastpath. I play on ps3 with the ps3 connected to the hh3 ethernet port. I always assumed that the lag was due to the over zealous lag comp, but now i'm not so sure.
 
I noticed that if I reboot the modem before playing then I can play the game with a flawless connection for 2 hours, after which the lag monster starts creeping in. (I know rebooting the modem can mess with the sync rate but it hasnt changed mine)
 
So is it a case that during the two hours playing the DLM kicks in or bt's p2p throttling kicks in and starts messing with my connection? or is it that after being on for a few hours and a few FEC/HEC errors the modem starts to get flustered? has it got problems clearing it's cache? I don't know kuch about the technology, does anyone have a good guess as to what the problem is or how i can keep the original connection?
 
thanks guys

[Bald_Eagle1]

Assuming you are using a Huawei HG612 modem, it should be noted that the GUI mis-reports CRC & FEC Errors.

The "real" data is obtained via telnet command xdslcmd info --stats

The alternative method is to use the Windows graphing scripts that will log the connection graphically, that might just identify what the problem might be (see attached example)

EDIT:

You may just be using a HG612 modem connected to an ECI DSLAM.
This combination does appear to suddenly start clocking up massive FEC/RSCorr error counts that may have an effect on a connection's throughput.
Rebooting the modem does stop that issue (but only for a while).

I use a Huawei HG612 connected to a Huawei DSLAM so don't see that particular problem.
My speed problems are due to being up to 1000m from the cabinet.

[McNugget]

Thanks for the reply

Is there anyway of finding out what type of dslam i'm connected too?

I'll make a few graphs when im at home and maybe someone could shed a little light on them

[Bald_Eagle1]

This is the band plan from a Huawei DSLAM:-

Discovery Phase (Initial) Band Plan
US: (0,95) (868,1207) (1972,2783)
DS: (32,859) (1216,1963) (2792,3959)


This is the tone band plan from an ECI DSLAM:-

Discovery Phase (Initial) Band Plan
US: (0,95) (880,1195) (1984,2771)
DS: (32,859) (1216,1959) (2792,4083)

That data is obtained via xdslcmd info --pbParams in a telnet session (or from the graphing script).



Using xdslcmd info --vendor you can get this data (Huawei DSLAM - Broadcom chipSet):-

ChipSet Vendor Id:      BDCM:0xa350
ChipSet VersionNumber:  0xa350
ChipSet SerialNumber:

[biohead]

Sorry for kinda butting into this thread, but is it definitely shown that using a HG612 with an ECI DSLAM may slow down your connection now?

I remember reading not so long ago that BTOpenreach installers were permitted to use any combination of modem, regardless of the DSLAM manufacturer. I'm guessing any effect isn't huge, but slightly noticeable to the more eagle-eyed users?

[Bald_Eagle1]

Sorry for kinda butting into this thread, but is it definitely shown that using a HG612 with an ECI DSLAM may slow down your connection now?

No, it isn't definitely definite (yet).

From my comment above:-

This combination does appear to suddenly start clocking up massive FEC/RSCorr error counts that may have an effect on a connection's throughput.
Rebooting the modem does stop that issue (but only for a while).

One user who switched back to an ECI modem on an ECI DSLAM claims that Interleaving was eventually turned OFF again & sync/throughput speeds increased.

Once we can reliably gather & report connection stats from an unlocked ECI modem, we should be able to definitely confirm matters one way or the other.

I remember reading not so long ago that BTOpenreach installers were permitted to use any combination of modem, regardless of the DSLAM manufacturer. I'm guessing any effect isn't huge, but slightly noticeable to the more eagle-eyed users?

Yes, BS did confirm that engineers/technicians had recently received confirmation from OR that either the ECI or HG612 modem could be used, regardless of the DSLAM in use.
However, just because they are allowed to, doesn't necessarily mean it is the "right" thing to do.

I am led to believe the difference really is noticeable, but I haven't experienced it for myself as I don't have an ECI modem to test on my connection's Huawei DSLAM.

[McNugget]

Right I've got the stats, i assume everything looks ok with them?

Sorry I don't know how to make them smaller

Here's an older one



And a new one



and one after a reboot

[Bald_Eagle1]

Those graphs look fine to me.
Perhaps QLN shows a a bit of noise though. -around 140dB is more usual/preferred, whereas yours shows around -120dB (slightly noisier).

They are only a snapshot though.
Do you always play in the evenings (when contention probably increases thus maybe slowing the throughput down)?

If the modem isn't rebooted, is the issue still apparent the next time you start to play (i.e. the next day)?

Using the 24/7 logging script might provide an indication as to when the connection deteriorates (higher error counts etc.)
A pattern may be detected, related to times of day or during heavy use etc.

You shouldn't really be seeing any FEC i.e. RSCorr errors as Interleaving is indeed OFF (don't use the FEC errors as reported by the modem's GUI though - they are WRONG).

If you do want to attach the graphs rather than having to upload them & post links, you could try out the attached GRAPH6.BAT. just use it to replace your current GRAPH6.BAT. The output montage is small enough to post in this forum.

EDIT:
Forgot to mention, your stats do confirm that you are connected to a Huawei DSLAM.

[McNugget]

Thanks for having a look bald eagle, the problems were happening at all times during the day,

I played earlier today without rebooting the modem and it was playing perfectly, a friend on infinity has also commented on how little lag he is seeing recently,so perhaps bt have done something to improve gaming, or maybe the game has been fixed a little, i'll have to try a game of BF3 to see if it has also improved.

I know bt infinity customers where having problems playing fifa last week so maybe whatever fixes they have done for that have also benefited other games.

As for the QLN, do you think another modem would provide a more stable experience, or is this purely a problem with my line.

I may start a 24/7 log tomorrow to guage how the line is behaving but i dont want to leave the laptop on all day and night

[Bald_Eagle1]

As for the QLN, do you think another modem would provide a more stable experience, or is this purely a problem with my line.

No, I don't think a different modem would make any difference.

It's not necessarily a problem either as your connection syncs at the full 80/20 with no Interleaving applied.
Maybe with a quieter line your attainable rate would increase, but as your connection is capped at the current maximum of 80/20 it wouldn't actually make any difference

I may start a 24/7 log tomorrow to guage how the line is behaving but i dont want to leave the laptop on all day and night

Looking at your other stats, I wouldn't really expect to see much in the way of problems over time, but it's always worth a check now & then, you never know.............

FWIW, I believe that BT have been carrying out quite a bit of network maintenance for the last week or so.
Maybe things will have improved & will settle down over the next few days.

[McNugget]

I didnt think a new modem would've made much of a difference,

Thanks for all of your help

[biohead]

BE: I've not unlocked my ECI modem yet, so only have very basic tools available to me. But it may be of use anyway.

I have my connection setup to be monitored by the TBB monitor - I swapped from the provided ECI to the HG612 in the middle of September. Just a few hours after the swap, the ping rose from about 13ms, to about 22ms. At the time, I thought nothing of it and put it down to more and more people being connected to the cabinet (I was the first on this particular DSLAM).

I swapped back to the ECI two days ago, and through the night the ping has dropped back down to 13ms. Just seems strange that in over a month it's remained at ~22ms, yet within 36 hours of going back to the ECI it's dropped straight back down.

I can't remember if the ECI GUI shows the stats, but if they do and someone is willing to send a 90 degree pin header to do the solderless unlock, I'll have a go and get some data. It may come in useful?

Edit: I am connected to an ECI cab - forgot to mention that bit!