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i4bipr - isdn4bsd IP over ISDN B-channel network driver
device "i4bipr" [count]
The i4bipr driver interfaces the IP subsystem of the operating system
with the isdn4bsd package so that transport of IP packets over an ISDN
link is possible.
The driver just packs IP packets without anything appended or prepended
into raw HDLC packets on the B channel and transfers them to a remote
site. IP packets received from the remote site are queued into the local
IP protocol stack.
The format of the resulting packet on the B channel is:
(HDLC opening flag) (IP-packet) (CRC) (HDLC closing flag)
In the case where an IP packet for a remote site arrives in the driver
and no connection has been 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(1) with the ipr interfaces.
The driver optionally (when compiled with the IPR_VJ option) provides Van
Jacobsen header compression, under control of the link0 and link1 options
link0 Apply VJ compression to outgoing packets on this
interface, and assume that incoming packets
link1 Check incoming packets for Van Jacobsen
compression; if they appear to be compressed,
automatically set link0.
The default values are on for link1 and off for link0.
tcpdump(1), bpf(4), isdnd.rc(5), isdnd(8)
The i4bipr device driver and this manpage were written by Hellmuth