10.4 Running DLPI Over LLC2

The stream architecture for LLC2 must be:

The previous version of the LLC2 driver did not carry out plumbing and PPA assignment, and applications that were designed to run directly over LLC2 were obliged to perform these steps themselves. The LLC2 driver supplied with Solstice X.25 9.2 now takes care of these tasks at system boot time, by means of /etc/rc2.d/S40llc2.

The relationship between the PPA and a particular LAN device is defined by the files in the directory /etc/llc2/default. Instead of choosing an arbitrary PPA and configuring LLC2 to use it, an application must find the PPA that is associated with the required LAN device and attach to it. Applications need now only do the following:

• determine the PPA associated with the required LAN device;

• open /dev/llc2;

• issue a DLPI attach request for the desired PPA.

Two routines have been added to the Solstice X.25 code to take account of the change in the LLC2 driver:

Table 10-1 Solstice X.25 routines to associate PPA with a LAN device

Routine	Description
x25_device_instance()	Finds the LAN device for a given X.25 link.
x25_device_to_ppa()	Finds the LLC2 PPA assigned to that LAN device.

See "11.1.2 Message Primitive Sequence Summary", for additional information.