[Ukfreebsd] Internal ADSL2 Card

Bruce M Simpson bms at incunabulum.net
Wed Jan 28 15:22:58 GMT 2009


O'Connor, Kevin wrote:
> I suppose I could always pull my finger out and write a driver for one
> of the common chipsets.
>   

    Welcome to a bucket of dildoes.

    The ITU has pretty much mandated the existence of ATM forevermore in 
the form of G.DMT-lite, and this was reflected in BT's IPStream network 
offering being ATM based at the point of delivery.   I don't know if 
this is the case for ADSL2+ still.

    Whether it's for the sake of protectionism, herd behaviour, or just 
plain slackness, I care not, but, there is more than one way to slap a 
clock line on to turn copper into an isochronous comms channel, and come 
on, Ethernet is even being used for avionics now.

    Hint: Netgraph and MPD is probably the way to go. An ng_pppoa node 
would need to be written. The netnatm code is "good enough" for 
FreeBSD's userland ppp to run on, but all those context switches with Mr 
tun(4) suck for serious use.

    End-station stuff for ADSL is always PVC based, so there is no need 
to implement ATM SVC signalling -- it should be a simple matter of 
writing a driver which conforms to netnatm.
    And besides, the vendors never did give out their switch secrets -- 
almost all publicly published ATM specs conveniently leave switching ops 
as "implementation defined", probably another way of saying, "give us 
the money or the project gets it".

    If you really want to touch this tar baby, I have partial code, ATM 
cards, and a G.DMT external modem with an ATM25 port, ready to send to 
you, the willing victim.
    The ATM25/10mbps ethernet dual mode switch I left at ICSI in 
Berkeley, is probably still in the corner office I shared with Luigi and 
Marko gathering dust.

Skip Ford volunteered a while back. "He went down to the generators, and 
never came back..."

love and rockets
BMS


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