phyRe technology

[roseway]

Poking around in the configuration options in the new DGTeam firmware for DG834GT I see one called phyRe - Impulse Noise Protection. This is apparently a Broadcom-specific feature, which is supposed to improve the stability of a connection by removing impulse noise from the signal.

What isn't at all clear (to me) is whether this capability exists on all types of connection, or just ADSL2+, and whether it depends on specific DSLAM/MSAN types. Information on the net seems to be rather thin. Does anyone know more about this?

[pintosal]

From what I've read, this will only work with Broadcom chip based DSLAMs, and where phyRe is switched on.

[waltergmw]

@ Pintosal,

The two wire modems always seem to show some sort of impulse noise protection in their diagnostics page, but usually it's just a constant figure - 2.46 TI, 1.64 Unknown, 2.0 TI.
However the new O2 one I showed yesterday with a Broadcom DSLAM gives a figure of 2.08, but there's seemingly no mention of phyRe.


Kind regards,
Walter

[sevenlayermuddle]

That's interesting,  I dug around and found some stuff, this being one of the best I came up with:

http://www.broadcom.com/collateral/wp/XDSL-WP101-R.pdf

My initial impression is that it's basically a more efficient error-correction mechanism involving physical layer retransmissions, so providing a lower BER. 
If it's based on physical layer ReTX, it's safe to assume it would need a co-operating DSLAM.

It seems to targeted at IPTV which apparently requires a lower BER (ie fewer physical layer errors) compared to more conventional internet traffic, which can rely on TCP/IP protocols for recovery from physical layer error.   I know nothing about IPTV, but if it can't benefit from TCP's error recovery then I can well speculate that it wouldn't work over normal DSL or, at least, it would require a more generous SNRM and hence a degradation of data rate.

I'd need to understand the document a lot better before speculating whether PhyR provides any benefit for users of applications that use TCP/IP, who don't need IPTV.

And in order to consume the document properly I'll need daylight, strong coffee, and a degree of motivation and attention span that I find hard to sustain these days, so perhaps I never will

- 7LM

[roseway]

That's an interesting document 7LM, so thanks. Like you I'll need daytime attention to take it in.

[HPsauce]

An interesting "fast read". More study required.
In the short term a quick question to my contacts at Be I think...
(my Be line is set at INP=2 I believe and has a Broadcom DSLAM and a DG834GT at my end with DGTeam firmware)