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Author Topic: ADSL2+ router  (Read 5534 times)

risk_reversal

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ADSL2+ router
« on: July 15, 2009, 12:58:23 PM »

Hi, my ISP upgraded my connection to ADSL2+ over the weekend. I have an ST585v6 [fw 6.2.29.2]. The downstream attenuation is 25db and the router's downstream sync is 12,942 / 848. The BT IP profile is 10,000.

Other dets as per below:

Line Attenuation (Up/Down) [dB]: 14,0 / 25,0
SN Margin (Up/Down) [dB]: 8,0 / 5,0
Output Power (Up/Down) [dBm]: 11,5 / 0,0 <-- odd that downstream power is 0,0

On Max my sync was 8132 and IP profile set at 7150.

Having a look on this site, the estimated downstream sync and IP profile based on my attenuation seems perhaps a bit on the low side.

The calculator on this site suggests figures nearer 

adsl2+ (21CN)  18144 kbps IP Profile  15000 kbps

I was thinking of purchasing a back up router (or even one that I could use as my main router and put the ST585v6 as backup). I did have a DG834 v2 as backup with ADSL Max and this worked fine but this model is apparently temperamental for ADSL2+.

I was thinking about a DG834GT and was wondering if the sync & IP profile would be better than the ST585v6.

I understand that the DG834GT and ST585v6 share the same Broadcom BCM6348 chipset. It was my intention to buy a cheapy off fleabay (possibly an ex-sky router and flash it to the Netgear firmware using the information on this site).

http://www.kitz.co.uk/routers/skyDG834GT_flash.htm

To this end I was wondering if anyone could give me some kind of feel for whether this would be a good move. Is the fact that these 2 units share the same Broadcom chipset an indication that they will both behave pretty much alike in term of sync speed?

21CN is having some issues after the roll out that was carried out by BTw over the weekend. Some are having issues with the MSAN's chipset. Some MSAN's use the Fujitsu and others the Huawei Infineon. The latter is causing issues for some users and that is the chipset that my ST585v6 is confirming that I have.

I too am having issues with wildly variable speeds and poor connection speeds although my router is connecting and not rebooting incessantly. However, this merely as an aside.

The thread below is interesting in the event that it may have escaped your attention.

http://www.dslzoneuk.net/forum/viewtopic.php?f=28&t=16015&p=137421

Any help re router recommendations much appreciated.

Cheers
« Last Edit: July 15, 2009, 01:17:32 PM by risk_reversal »
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HPsauce

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Re: ADSL2+ router
« Reply #1 on: July 15, 2009, 01:24:45 PM »

The commonest cause of poor speeds, especially with ADSL2+, is your own wiring.
A good ADSL2+ ISP will know this and be able to advise - who is your ISP?

Meanwhile, post the full stats here for more advice.

A change of router is probably irrelevant.
(My ISP supplies a Thomson but I choose to use a DG834GT I already had - both give me very similar results with ADSL2+)
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kitz

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Re: ADSL2+ router
« Reply #2 on: July 15, 2009, 01:28:47 PM »

Very Quick reply as Im about to go out.. so just some thoughts.


>> 21CN is having some issues after the roll out that was carried out by BTw over the weekend

again! /cynic mode

>> Some MSAN's use the Fujitsu and others the Huawei Infineon.

AIUI.. most of them should be fujitsu - have you tried IDing the remote chipset of the msam youre attached to?

>> Is the fact that these 2 units share the same Broadcom chipset an indication that they will both behave pretty much alike in term of sync speed?

Not necessarily... on my own (short) line my ST585v6 outperforms any other router I have. There isnt that much difference though between the DG834GT and the ST585v6 (about 500kb lower on the Netgear, and the ST seems slightly more stable for me personally).  Yet on other lines the DG834GT often performs best. 

Many people rave about the 2Wires.. but my sync is about 2Mb less - and it wont do Annex_M so in theory it should sync higher! Its often a case of suck it and see without any guarantees Im afraid.

I'm definitely not impressed with the 585v7 (same BCM chipset) but with different board.. so bear in mind that its not always down the chipset... and theres a few other things such as board and firmware that can make a difference.

However, If you are looking for a cheap 2nd router then you could do much worse than trying an ex-sky DG834GT.

>> The calculator on this site suggests figures nearer 

based on optimised line and 6dB target SNR.
I dont think BT seem to have adsl2+ quite right yet :(
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toulouse

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Re: ADSL2+ router
« Reply #3 on: July 15, 2009, 01:38:13 PM »

Quote from Kitz 'I don't think BT seem to have ADSL2+ quite right yet'


You can say that again !!!!


A VERY CONFUSED AND ANGRY

toulouse
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risk_reversal

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Re: ADSL2+ router
« Reply #4 on: July 15, 2009, 03:00:56 PM »

Quote
The commonest cause of poor speeds, especially with ADSL2+, is your own wiring.

Checked all the wiring when I got ADSL Max and my wiring is not the issue here. Plus, I often check that nothing has so to speak changed. But it doesn't hurt to check again just in case.

Quote
Meanwhile, post the full stats here for more advice.

Uptime: 1 day, 6:38:33 (router rebooted on tuesday and resynced at a slightly higher rate for both up/dn)

Modulation: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 848 / 12.942
Data Transferred (Sent/Received) [MB/GB]: 152,35 / 1,13
Output Power (Up/Down) [dBm]: 11,5 / 0,0
Line Attenuation (Up/Down) [dB]: 14,0 / 25,0
SN Margin (Up/Down) [dB]: 8,0 / 6,5

Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 1 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 142 / 0

FEC Errors (Up/Down): 0 / 31.011.270
CRC Errors (Up/Down): 0 / 8.025
HEC Errors (Up/Down): 0 / 7.863

---------------------------------------------

Quote
Some MSAN's use the Fujitsu and others the Huawei Infineon - have you tried IDing the remote chipset of the msam youre attached to?

Well the ST585 is reporting IFTN as Remote. Do you think that this is questionable? EDIT: Searched for IDing, but cannot find it. What it is?

Quote
I'm definitely not impressed with the 585v7 (same BCM chipset) but with different board.. so bear in mind that its not always down the chipset... and theres a few other things such as board and firmware that can make a difference.

Good point. HW can be so fickle as we are all well aware.

Quote
However, If you are looking for a cheap 2nd router then you could do much worse than trying an ex-sky DG834GT.

I need a spare router in any case plus for trouble shooting it's also indespensible.

Quote
Its often a case of suck it and see without any guarantees Im afraid.

Yes, I know what you mean, hence me trying to get a feel for the 834GT and a cheapy (15) at that as I don't want to spend serious money on a piece of HW that may possibly spend most of it's life in the cupboard.

Quote
'I don't think BT seem to have ADSL2+ quite right yet'. You can say that again !!!!

Snap.

Many thanks for the info

Cheers
« Last Edit: July 15, 2009, 03:04:50 PM by risk_reversal »
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jeffbb

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Re: ADSL2+ router
« Reply #5 on: July 15, 2009, 06:36:35 PM »

Hi

quote Hi, my ISP upgraded my connection to ADSL2+ over the weekend.

If you get an upgrade do you go through the 10 day learning period again?

Regards Jeff
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orainsear

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Re: ADSL2+ router
« Reply #6 on: July 15, 2009, 08:02:24 PM »

Vendor ID (Local/Remote): TMMB / IFTN

IFTN ATUC code = Infineon chipset.

Searched for IDing, but cannot find it. What it is?

Shorthand for 'identifying' would be my guess.


The Sky DG834GT would be an excellent choice.  I wonder if it may be worth you trying a Texas Instruments (TI) chipset, e.g. a Sky Netgear DG934G (DG834Gv3 in disguise) can be bought very cheaply.  Infineon bought out the TI DSL business a while back.  Other than that some of the Draytek gear uses Infineon chipsets.
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risk_reversal

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Re: ADSL2+ router
« Reply #7 on: July 16, 2009, 10:07:22 AM »

Quote
The Sky DG834GT would be an excellent choice.  I wonder if it may be worth you trying a Texas Instruments (TI) chipset, e.g. a Sky Netgear DG934G (DG834Gv3 in disguise) can be bought very cheaply.  Infineon bought out the TI DSL business a while back.  Other than that some of the Draytek gear uses Infineon chipsets.

Possibly an idea and for much the same reason that I got the ST585 with MAX ie the MSAN had an Alcatel [ALCB] chipset.

Not sure, the salient question must therefore again center around the issue of router / MSAN compatibility much as it was with MAX and to this end I guess that 21CN ADSL2+ users need more time to experience how the new ADSL2+ chipsets [Fujitsu / Infenion] behave with various router chipsets.

Cheers
« Last Edit: July 16, 2009, 10:42:15 AM by risk_reversal »
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orainsear

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Re: ADSL2+ router
« Reply #8 on: July 16, 2009, 09:20:40 PM »

The DSL ZoneUK thread seems to suggest upgrading the 585v6 firmware to version 8.2.2.5 made quite a difference - perhaps it's worth giving it a try.
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risk_reversal

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Re: ADSL2+ router
« Reply #9 on: July 18, 2009, 12:17:29 PM »

Well I got a hold of a DG834GT [sky & flashed it] and here are my results

I tested the above router yesterday with the Netgear FW v1.02.09 and the latest DGTeam FW v1.02.16 build 0848.

Here are the stats of the ST585 prior to the change
10,722kbps  / 851 kbps
SNR  8.5 / 8
ATT   25/ 14

DG834GT with Netgear v1.02.09

10,778 kbps [basically unch / 803 kbps [dn from 851]
SNR 9.75 [dnstream] / 7.5 [upstream]
Attenuation (Dn/Up) [dB]: 28,5 / 15,8 [both up]

The DGTeam FW performed more or less the same.

I then tried running a commercial speedtest and the download speed was in the first part of the test very erratic and low fluctuating between 500 kbps 2,000 kbps. The best speedtest result I got was 2,200 kbps. This was for both the Netgear and DGTeam FWs.

I reconnected the ST585 and got 11,466 kbps / 851 kbps.

This morning I checked the ST585 which had resynced lower on the downstream.

9,964 kbps / 851 kbps
SNR 12.5 / 8

I connected the ST585 into the main BT socket with the following results

9,620 kbps [dn] / 888 kbps [up from 848]
SNR 12.5 [dnstream] / 11.5 [upstream]
Attenuation (Dn/Up) [dB]: 24,5 / 14,0

Apart from a lower downstream sync, the only noticeable item was the 3.5db gain on up SNR.

I am not sure what to do right now. In the first instance I have sent my ISP an email asking whether BT are aware of any [additional] known new issues on 21CN ADSL2+. There were some earlier this week which were allegedly resolved.

At the heart of this problem, I keep thinking about this Infineon chipset at the exchange and the number of posts I have seem with people mentioning this. I have as yet not noted any posts mentioning the Fujitsu as being problematic.

The Infineon is perhaps highly discerning as regards compatiblilty and perhaps the broadcom chipset is not ideally suited.

I have tried to search for more info but cannot find anything. Perhaps at this stage it's still too early.

I think I should try another router [chipset] but am at a loss.

Any info, thoughts or ideas much appreciated

Cheers
« Last Edit: July 18, 2009, 12:28:39 PM by risk_reversal »
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jeffbb

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Re: ADSL2+ router
« Reply #10 on: July 18, 2009, 06:11:04 PM »

Hi

BE CAREFUL all this switching routers and resynching has probably already raised your target SNR  to 12 db
I wouldn't do anymore tests for awhile you are running the risk of raising your target even more .
have a look at the link below if you are unsure about SNR ,SNR margin and Target SNR some very good explanations.
http://www.kitz.co.uk/adsl/linestats.htm
Regards Jeff :)
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