NAME
ippp
- ISDN synchronous PPP network driver
SYNOPSIS
pseudo-device ippp count
DESCRIPTION
The
ippp
driver interfaces the IP subsystem of the operating system with the
ISDN layer so that a transport of IP packets over an ISDN link
is possible.
For configuration of the
ippp
driver, either the
ipppctl(8)
utility is used or it is configured via
isdnd(8)
and its associated
isdnd.rc(5)
file.
In case an IP packet for a remote side arrives in the driver and no
connection is established yet, the driver communicates with the
isdnd(8)
daemon to establish a connection.
The driver has support for interfacing to the
bpf(4)
subsystem for using
tcpdump(8)
with the
ippp
interfaces.
The
ipppctl(8)
utility is used to configure all aspects of PPP required to connect to a
remote site.
LINK0 and LINK1
The
link0
and
link1
flags given as parameters to
ifconfig(8)
have the following meaning for the
ippp
devices:
link0
-
Wait passively for connection.
The administrative
Open
event to the Link Control Protocol (LCP) layer will be delayed until
after the lower layers signal an
Up
event (rise of
``carrier'').
This can be used by lower layers to support a dial-in connection where
the physical layer isn't available immediately at startup, but only
after some external event arrives.
Receipt of a
Down
event from the lower layer will not take the interface completely down
in this case.
link1
-
Dial-on-demand mode.
The administrative
Open
event to the LCP layer will be delayed until either an outbound
network packet arrives, or until the lower layer signals an
Up
event, indicating an inbound connection.
As with passive mode, receipt of a
Down
event (loss of carrier) will not automatically take the interface
down, thus it remains available for further connections.
The
link0
flag is set to
off
by default, the
link1
flag to
on.
SEE ALSO
bpf(4),
isdnd.rc(5),
ipppctl(8),
isdnd(8),
tcpdump(8)
AUTHORS
The
ippp
device driver was written by
Joerg Wunsch <joerg@freebsd.org>
and then added to ISDN4BSD by
Gary Jennejohn <gary@freebsd.org>.
This man page was written by
Hellmuth Michaelis <hm@kts.org>.