Using /31 for router links

Michael Sokolov msokolov at ivan.Harhan.ORG
Sat Jan 23 20:50:56 UTC 2010

Brielle Bruns <bruns at> wrote:

> Back in the days of Rhythms and Copper Mountain gear, Netopia had the D 
> series routers which were actually xDSL to DSU units.

Yes, I am very familiar with them:


As that page explains, they are only pseudo-DSUs though.  I much much
prefer a true bit-transparent DSU:


I have also designed and built an SDSL to EIA-530 DSU of my very own:


On the latter I have the hardware (the page above has a photo of the
board), but the operational software (or firmware if you will) remains
to be finished.

> Though, I'm not sure they'd work these days,

Only in the very limited geographic footpring of what used to be
- they are the last remaining semi-major operator of CM DSLAMs:


My big goal is to make my own DSU which I have just mentioned function
as a Layer 2 converter (FRF.8 and friends) from Nokia SDSL/ATM served by
Covad to HDLC.

> nor do I think 
> they came in ADSL models either.

I don't think anyone have *ever* used V.35 & friends with ADSL -
probably because those who would want V.35 (i.e., people like me) would
find ADSL morally offensive. :-)


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