Subject: Re: autoconfiguration question
To: Bill Studenmund <>
From: Stefan Grefen <>
List: tech-kern
Date: 05/28/1997 18:38:59
In message <>  Bill Studenmund wrote:

> Since there are other uses of an hdlc link than just sppp, we need a way
> to tell the port what to stack on top. We don't have a way to do this with
> network interfaces at the moment (they assume that all attachable protocols
> work at once). With tty's, we have line disciplines.
> My thought for the hdlc device was to add a character device (seperate
> from any async tty character device) on the port and give it line
> disciplines. The character side of the interface would be much like
> the char side of a tun interface (read and write whole packets).
> In ppp mode, control packets could come down this interface.
> What other ioctls are needed?

A whole lot, but they are part of the line-dicipline. As long as you can 
attach that (eg. on a tty-style device) your're fine.

But my point is that there seems to be a general need for something
like linedicplines/protocol stacking for network interfaces. 
(It would be great to just modload a new IP-protocol or an add on to UDP ...).

With ISDN you have a network protocol with different services (voice,
various data-protocols etc.) and it would be great to reuse as much 
code as possible. But the showstopper is that you can't add additional
protocols easily (try adding PPP on top of UDP or TCP for example, usefull 
tunneling ...) to existing protocol stacks.
As someone  else stated in this thread, I don't want SYSV-Streams !!! 
As I think of it of it, may be I can create a device driver that can 
do it (I need this for my daytime job anyway I found out today,
the streams stack in some commercial unixes is way to bad (no not
our NONSTOPUX that would've be to easy .. :-(  )

> Take care,

Don't have time for that :-)))

> Bill

Stefan Grefen                                Tandem Computers Europe Inc.                       High Performance Research Center
If a group of N persons implements a COBOL compiler, there will be N-1
passes.  Someone in the group has to be the manager.
                -- T. Cheatham