Re: Synchronous board drivers

Paul Fulghum (paulkf@austin.rr.com)
Mon, 05 Jul 1999 19:02:27 -0500

Alan Cox wrote:
> > If you have a smart firmware-driven PPP board, then wouldn't it be
> > doing the ppp negotiation itself, thus removing the need for pppd and
> > the kernel ppp driver? Wouldn't it look much more like an ethernet
>
> Yes. However two things apply here that are important
>
> 1. It may do PPP, but if I flip it to X.25 it may not do X.25, so the
> board itself needs a control of how it hands packets around.
> 2. I may want to be able to add a board specific ioctl to pick hardware
> (low cpu overhead) v software (multilink, cool feature set) PPP

Wouldn't the 'smart mode' (firmware ppp implementation) operate
outside the scope of a generic sync board or ppp channel interface?

The driver for such a board could offer both an ethernet emulation
(smart mode)
interface (eliminating the need for pppd/ppp.o) *and* a generic
sync/channel (sw mode)
interface. Instead of ioctl in the generic i/f to switch between the
two, the driver
would create two devices for each physical port (similar to the normal
and call out
devices for a serial port). Open the ethernet emulation device and get
smart mode. Open
the generic sync device and get a generic interface that allows sending
of any kind of
synchronous frames (x.25, ppp, etc).

It does not make any sense to me to combine a higher level interface
(network/LAN emulation)
for PPP/Frame Relay or whatever, with the lower level generic sync
interface.

-- 
Paul Fulghum
paulkf@austin.rr.com
"what kind of party is this?
 there's no booze and only one hooker..." - Bender


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