[AusNOG] DSL Line Stats

[Joseph Goldman]

 From my understanding - lower SNR targets can also improve sync speed 
hence why people like iiNet offer it on the 'ThrillSeeker' kind of naming.

I may be wrong though.

On 30/09/14 23:51, Shane Short wrote:
> That's... not strictly true.
>
> SNR indicates the noise margin, but doesn't necessarily dictate if 
> line is "good" or not. What're you really interested in are CRC 
> errors, or Errored Seconds (ES). I've seen lines that have been able 
> to run with a solid SNR of 3dB with minimal CRCs and a resync once a 
> month.
>
> It's also worth noting that if you're on Open 2 (20/1) on Telstra 
> Wholesale, your default target SNR *is* 6dB, so assuming an SNR that 
> low means the line is fubar is a bit of a red herring.
>
> Different profiles on different ISPs/DSLAMS will often set a target 
> SNR when they're initially syncing. From memory you can use the 
> following profiles on some ISPs to hit an SNR target:
>
> - Telstra Wholesale Default - 6dB
> - Telstra Wholesale "Stability Profile" 15dB
> - iiNet Thrillseeker - 7dB
> - iiNet Standard - 9dB
> - iiNet Controlled - 15dB
>
> To recap, a low SNR doesn't mean you're having issues, but having a 
> high one helps prevent them.
>
> -Shane
>
>
> adamn at eyemedia.com.au wrote:
>> This was one I stumbled on the web sometime back, I can't find the 
>> back reference for it :\
>>
>> *SNR is Signal to Noise Ratio* (aka Noise Margin or Signal to Noise 
>> Margin)
>> Relative strength of the DSL signal to Noise ratio. 6dB is the lowest 
>> dB manufactures specify for modem to be able to synch. In some 
>> instances interleaving can help raise the noise margin to an 
>> acceptable level. The higher the number the better for this measurement.
>>
>> 6dB or below is bad and will experience no synch or intermittent 
>> synch problems
>> 7dB-10dB is fair but does not leave much room for variances in conditions
>> 11dB-20dB is good with no synch problems
>> 20dB-28dB is excellent
>> 29dB or above is outstanding
>>
>> *Loop Att. is Line Attenuation*
>> Measure of how much the signal has degraded between the DSLAM and the 
>> modem. Maximum signal loss recommendation is usually about 60dB. The 
>> lower the dB the better for this measurement.
>> 20dB and below is outstanding
>> 20dB-30dB is excellent
>> 30dB-40dB is very good
>> 40dB-50dB is good
>> 50dB-60dB is poor and may experience connectivity issues
>> 60dB or above is bad and will experience connectivity issues
>>
>> *Output Power*
>> How much power modem (upstream) or DSLAM (downstream) is using. 
>> Maximum recommended is about 15dB. The lower the power the better for 
>> this measurement.
>>
>> Cheers,
>> Adam
>>
>>
>>
>> From: Travis <mallik at internode.on.net>
>> To: Jason Reid <jasereid at gmail.com>,
>> Cc: "AusNOG at lists.ausnog.net" <AusNOG at lists.ausnog.net>
>> Date: 30/09/2014 05:47 PM
>> Subject: Re: [AusNOG] DSL Line Stats
>> Sent by: "AusNOG" <ausnog-bounces at lists.ausnog.net>
>>
>> ------------------------------------------------------------------------
>>
>>
>>
>> I always thought this was a pretty good explaination:
>> _
>> __http://www.kitz.co.uk/adsl/linestats.htm_
>>
>> On 25 September 2014 17:12, Jason Reid <_jasereid at gmail.com_ 
>> <mailto:jasereid at gmail.com>> wrote:
>> I'd also be interested in this.
>>
>> Regards
>> Jason Reid
>>
>>
>> On Thursday, 25 September 2014, Jacob Kino 
>> <_jacob at interconnekt.com.au_ <mailto:jacob at interconnekt.com.au>> wrote:
>> Hi All,
>>
>> Someone in our team has asked for a good document to explain DSL line 
>> stats, primarily in the context of interpreting wholesale DSL line 
>> stats reports.
>>
>> I had a look at our carrier’s product definition document but it 
>> doesn’t seem to speak much about layer 1, wondering if anyone had a 
>> good reference they could point to, ideally that has some real world 
>> reference values in an Australian context.
>>
>> Cheers,
>>
>> Jacob
>>
>> *Jacob Kino*
>>
>>
>>
>> Suite 5, 25-27 Izett St
>> Prahran, VIC, 3181
>> Hi *
>> e-mail *jacob at interconnekt.com.au *
>> phone*     1300 852 842*
>> fax *         03 9011 6298*
>> www * _www.interconnekt.com.au_ <http://www.interconnekt.com.au/>
>>
>>
>>
>> -- 
>> Jason Reid
>>
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