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From: Archie Cobbs <archie@whistle.com>
Message-Id: <199611300240.SAA10223@bubba.whistle.com>
Subject: Re: isdn
In-Reply-To: <199611280125.TAA13940@rocket.comtrol.com> from Amir Farah at "Nov 27, 96 07:25:18 pm"
To: amir@comtrol.com (Amir Farah)
Date: Fri, 29 Nov 1996 18:40:58 -0800 (PST)
Cc: hackers@freebsd.com
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> I have an ISDN board along with software from LINK TECHNOLOGY which provides
> layers 1 to 3 for an ISDN board. I was able to implement layer 4 as a driver
> in FreeBSD 2.1 and invoke layers 1 to 3 from the LINK software. The Link
> software sees the board and configures the directory # and spid # I
> provided. I could code a number and spid for an outgoing call and the LINK
> software would do it for me. The problem is: how to write the driver to
> support ppp (which is all I want to do at this point). Eventually multi-link
> ppp.......... 

Howabout this..  manifest each B channel as a /dev entry, in the
form of a simple HDLC framer. E.g., /dev/isdnb0 and /dev/idsnb1, where
writing to the device (which is atomic) causes the written data to get
a 16 bit checksum added to it and sent out as a synchronous packet.
Similarly, reading reads in the next valid HDLC frame sans checksum.

Then use mpd (in /incoming of ftp.freebsd.org) to set up multi-link
PPP across the two devices... you'll have to add a new link type for
the B channels, which is pretty easy (and I can help).

-Archie

___________________________________________________________________________
Archie Cobbs   *   Whistle Communications, Inc.  *   http://www.whistle.com