IRIP(4)

NAME
irip - Raw IP over ISDN network driver

SYNOPSIS
pseudo-device irip count

DESCRIPTION
The irip driver interfaces the IP subsystem of the operating system with the ISDN layer 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(8) with the irip interfaces.

The driver optionally (when compiled with the IRIP_VJ option) provides Van Jacobson header compression, under control of the link0 and link1 options to ifconfig(8):

link0
    Apply VJ compression to outgoing packets on this interface, and assume that incoming packets require decompression.
link1
    Check incoming packets for Van Jacobson compression; if they appear to be compressed, automatically set link0.

The default values are on for link1 and off for link0.

SEE ALSO
bpf(4), isdnd.rc(5), isdnd(8), tcpdump(8)

AUTHORS
The irip device driver and this man page were written by Hellmuth Michaelis <hm@kts.org>.