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.\" Copyright (c) 1997, 2000 Hellmuth Michaelis. All rights reserved.
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.\"	$Id: i4bisp.4,v 1.1.1.1 2001/01/05 15:43:17 martin Exp $
.\"
.\" $FreeBSD$
.\"
.\"	last edit-date: [Thu Aug 31 10:40:17 2000]
.\"
.Dd August 31, 2000
.Dt I4BISPPP 4
.Os
.Sh NAME
.Nm i4bisppp
.Nd isdn4bsd synchronous PPP over ISDN B-channel network driver
.Sh FreeBSD SYNOPSIS
.Cd pseudo-device \&"i4bisppp\&" Op count
.Sh NetBSD SYNOPSIS
none
.Sh DESCRIPTION
The
.Nm
driver interfaces the IP subsystem of the operating system with the 
isdn4bsd package so that a transport of IP packets over an ISDN link
is possible.
.Pp
The driver is just a glue layer between Serge Vakulenko's sppp 
backend and the ISDN4BSD package.
.Pp
Beginning with i4b version 0.95 (and only for FreeBSD), the sppp 
subsystem was integrated into the
.Nm
driver to support more i4b/ISDN specific options. As a consequence it is no
longer necessary to add a "options sppp" to your kernel 
.Xr config 8
file. For configuration of the i4bsppp driver, either the
.Xr ispppcontrol 8
utility is used or it is configured via
.Xr isdnd 1
and its associated
.Xr isdnd.rc 5
file.
.Pp
In case an IP packet for a remote side arrives in the driver and no
connection is established yet, the driver communicates with the
.Xr isdnd 8
daemon to establish a connection.
.Pp
The driver has support for interfacing to the
.Xr bpf 4
subsystem for using
.Xr tcpdump 1
with the
.Nm isp
interfaces.
.Pp
The 
.Xr ispppcontrol 8
utility is used to configure all aspects of PPP required to connect to a
remote site.
.Sh LINK0 and LINK1
The
.Em link0
and 
.Em link1
flags given as parameters to
.Xr ifconfig 8
have the following meaning for the
.Nm isp
devices:
.Bl -tag -width link0 -compact
.Pp
.It Li link0 
wait passively for connection
.Pp
.It Li link1
auto-dial on output
.El
.Pp
The 
.Em link0 
and 
.Em link1 
flags are set to
.Em off
by default.
.Pp
See
.Xr sppp 4
for a more detailed discussion of the flags,
.Pp
.Sh SEE ALSO
.Xr isdnd 8
.Xr isdnd.rc 5
.Xr ispppcontrol 8
.Xr sppp 4
.Xr bpf 4
.Xr tcpdump 1
.Sh AUTHOR
The
.Nm
device driver was written by 
.An Joerg Wunsch Aq joerg@freebsd.org
and then added to ISDN4BSD by 
.An Gary Jennejohn Aq gary@freebsd.org .
.Pp
This manpage was written by 
.An Hellmuth Michaelis Aq hm@kts.org .