The Care and Feeding of ISDN4BSD
5.6.1 FreeBSD 4.x and	5 Installation and Kernel	5.7.1 Compiling and Installing

5.7 Additional Kernel Configuration and Compiling and Booting a new Kernel

The following steps are common to all types of passive ISDN cards, ISA, PnP or PCI. For simplicity, i assume we still configure a kernel for the Teles S0/16 card.

Note: for FreeBSD >= 5.0 replace the keyword pseudo-device with the keyword device in the following examples !

Some more lines have to be added to your new kernel configuration file. The following pseudo⁵ device drivers must be added to the kernel configuration file:

pseudo-device "i4bq921"

pseudo-device "i4bq931"

These 2 lines add support for the layer 2 and layer 3 protocols to the kernel.

pseudo-device "i4b"

pseudo-device "i4btrc" 4

pseudo-device "i4bctl"

With this 3 lines, the drivers for the three required drivers interfacing to the userland are added. The devices are later visible as /dev/i4b, which is required for the isdnd, /dev/i4btrc which is required for the operation of isdntrace and /dev/i4bctl, which is required by the isdndebug program.

pseudo-device "i4brbch" 4

pseudo-device "i4btel" 4

pseudo-device "i4bipr" 4

pseudo-device "i4bisppp" 4

This lines add support for the /dev/i4brbch<n> devices, the /dev/i4btel<n> devices, for the ipr<n> network interfaces and for the isp<n> network interfaces.

The ipr driver is able to do Van Jacobsen (VJ) header compression. To enable this, the line:

options IPR_VJ

needs to be entered into the kernel configuration file. Adding this option is recommended in case you want to use the ipr<n> devices.

Another option for the ipr driver is the possibility to log the contens of the first few IP-Packets which cause a dial to a remote system (this is helpful to find aout the cause for dialouts!):

options IPR_LOG=n

where n has to be set to the number of packets to log for a new connection.