Broadband Related > FTTC and FTTP Issues

Crosstalk impact on DSLStats Graphs

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jaydub:
There is a lot of posts on here that state that crosstalk is one of the major reasons for degradation of people's max attainable / actual sync rate.

I've not really seen any mention of what impact it has on other line characteristics.

As crosstalk has to impact the noise floor, presumably it would impact both the SNRM and QLN graphs on DSLStats.

I have certainly seen some degradation of max attainable on my line, since I first got VDSL back in October 2016, when my may attainable downstream was ~110Mbps and this has now dropped to ~86Mbps and I can see a significant reduction in SNRM from 12.9dB down to 7.4 dB now.

I don't have any QLN graphs that predate the demise of MDWS, so can't do an equivalent comparison.  If i did have them back to 2016, would I also expect to see a significant change in the noise floor on the QLN graphs?

burakkucat:
If you calculated the average (arithmetic mean) over the entire usable bandwidth, I would expect a change to be noticeable as more cross-talk degrades the circuit's performance.

I have a small utility, anf, that performs the calculation. If you have access to a C-compiler, then you would be welcome to have a copy of the source code . . .

jaydub:
Thanks B*cat for the offer, but I don't have a C-compiler and it was more of a general question anyway.

I was just trying to establish whether the Connection speed, SNRM and QLN graphs were the ones that would be most obviously impacted by crosstalk and, in the case of QLN, how obvious the impact would be.

I just wish I had a QLN graph from when I had a d/s attainable of 105Mbps to compare against.

konrado5:

--- Quote from: burakkucat on July 17, 2018, 06:08:30 PM ---I have a small utility, anf, that performs the calculation. If you have access to a C-compiler, then you would be welcome to have a copy of the source code . . .

--- End quote ---
Does anf work on linux? Could you send me?

burakkucat:

--- Quote from: konrado5 on July 21, 2018, 03:50:04 PM ---Does anf work on linux? Could you send me?

--- End quote ---

Yes and yes. (You have a PM.)

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