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[snadge]

I wanted to ask a couple of questions but thought I would put them in the same post...

1) Does Firmware/ADSL Driver make much of a difference between the same chipsets in different router/modems for connection sync & stability? - i.e. having a router made by one manufacturer with a (for e.g.) BCM6361 chipet and another router made by a different manufacturer with the same 6361 chipset, they obviously must have their own versions of firmware and possibly ADSL Driver on there...does it make much of a difference? or are the fw's / ADSL Drivers identical?

2) CRC count creeping up overnight - has anyone else suffered the same phenomenon as me whereby CRC count creeps up during the night when the router/modem is not in use? I have and I have noticed it with all my routers where I could access stats, for e.g. last night on my new HG612 I had just a couple of CRC's before I went too bed and when I turned on PC before and checked I had 615 CRC's...whats all that about? then when I use it again its back to normal, the CRC's just slowly accumulate, but left overnight (not-in-use) it gathers hundreds??

3) is it possible to adjust SNRM on other chipsets other than Broadcom? - Im sure i read somewhere of a Trend chipset having this capability..cant remember where though.

4) does correcting errors add much latency to the transfer of data compared to the data not needing corrected?.? (will web pages be loading slower...even if microseconds...because of high amount of correctable errors? - I believe when data has to be 'corrected' then this takes time by the router to do before passing it on...just how much of a delay is this?

if anyone could put some answers to these I would really appreciate it

thanks

[SecTSys]

unfortunately i can't answer the second question Snadge, but I can attempt to answer your first!

My understanding of firmware. (described as best as i can though someone else may want to re-iterate what i have said in a clearer way!)

A new firmware update on a chipset should always provide solutions for stability issues bugfixes and other problems so unless you have a specific reason to not update the firmware on a piece of hardware, then it is always good practice to keep it updated.

But in your example a BCM6361 chipset on two different routers may need to have two different sets of instructions on it. if a netgear router and a BT Homehub had the same BCM6361 Chipset the instructions would still need to be different because of the difference with the hardware that the chip is providing instructions for.

so no the firmware between two products are not identical even if the chipset itself is.

[snadge]

thanks for that SectSys - and the Manufacturers/ISP's firmware could give different sync rates too yes? e.g. my Sky-Hub (6361) and a BT Home-Hub 3B (6361) could have different effects on the sync rate due to their firmware...

I have added a 3rd question:

3) is it possible to adjust SNRM on other chipsets other than Broadcom? - Im sure i read somewhere of a Trend chipset having this capability..cant remember where though.

thanks again for you answer and afforst to help unlock the 3B

[roseway]

1. The determinant for the ADSL performance would (I think) be the ADSL driver, and I think it's most likely that this driver will be supplied by the chipset manufacturer. When there's a firmware update it's not always obvious from the description whether the driver has been updated, or just the configuration and reporting functions. So a firmware update might improve ADSL performance/stability, or it might not.

2. I don't know the answer, but there's generally more interference during the hours of darkness, so any data that's transmitted is more likely to be subject to errors. The router exchanges data with the DSLAM/MSAN all the time, so there's always some data being transmitted, even when you're fast asleep.

3. I've never come across any non-Broadcom chipset which can be tweaked, but that's not to say that it doesn't exist.

[snadge]

thanks Eric - especially for making me realise I should of been on about ADSL Driver and not firmware on its own..

ive added a 4th question

4) does correcting errors add much latency to the transfer of data from router to PC.? (will web pages be loading slower...even if microseconds...because of high amount of correctable errors? - I believe when data has to be 'corrected' then this takes time by the router to do before passing it on...just how much of a delay is this?


thanks

[roseway]

4. Kitz has some excellent information on error correction: http://www.kitz.co.uk/adsl/error_correction.htm

(It doesn't add latency between the router and the PC, but it does add latency to the connection with the exchange.)

[snadge]

Thanks Eric I will take a gander... the reason I ask is because Iam going to be using sub standard SNRM (e.g. 3db) - when using these low noise margins the amount of correctable errors increases ten-fold (albeit still 0.1% of all traffic)

when I use 3-4db Noise margin my 'corrected' errors are around 0.1% of all traffic
when I use the standard 7db Noise margin my 'corrected' errors are about 0.01% of all traffic

Iam just curious to know how much delay there is in 'correcting' these errors, I wondered if when using low noise margins would my web-pages etc be loading that much slower?? - i may be wrong but I think its probably on a scale where its so small that corrected/not needing corrected you wouldnt notice the difference...only if cant be corrected and CRC occurs