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Curiosity only! But what do these stats mean and tell?

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Posts: 3,560
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Registered: ‎31-07-2007

Curiosity only! But what do these stats mean and tell?

I want to advance my knowledge, so will someone tell me the significance of
Bearer Generic Info               Downstream        Upstream 
INP          (DMT)          :        1.21            2.00
Delay        (ms)            :        7.96            8.00
R                            :        10                8
, please?
No one has to agree with my opinion, but in the time I have left a miracle would be nice.
Posts: 878
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Registered: ‎14-08-2009

Re: Curiosity only! But what do these stats mean and tell?

They are all something to do with interleaving.........
R is the number of RS check bytes  in a FEC data frame........I think
Which presumably means they will be zero for a fast path line (...errr I hope if I'm right!)
RS here refers to Reed Solomon whose althorighms of how unique checksums are calculated from a data stream form the basis of interleaving and the re-assembling of packets at the far(router) end - and in particular the correction of corrupted sections of the data frames back into what they should be.  This technology has at its basis designs of early rocket telemetry systems in the 1960's.
FEC means Forward Error Correction
INP and delay are something to do with impulse noise protection on the line/data stream  - ie very fast rise/fall spikes on the line which nothing short of an oscilloscope would see.
No one has really yet bottomed out the significance of the depth of the interleaving on the line and how this is set.  I know mine is always under normal circumstances at 64 downstream and 4 upstream - however when there was a fault on the line and syncs were all different the interleaving depth was changing as well.
More than that its all outside my technical competance.
Those who know more please feel free to say I've got it back to front!
I fear that the full explanation is so complex that without a background in the technology to understand/grasp the basics one is unable to really understand the detail.
Someone in particle physics said much the same to me sometime ago though added that they used a complete sub-set of the English langage as well with words that are never heard of outside the field of particle physics.