NetIPC 3000/XL Programmer's Reference Manual (5958-8600)

42 Chapter1
NetIPC Fundamentals
Direct Access to Level 3 (X.25)
Facility Field
The X.25 facility field is built from the facility set configured with
NMMGR. With direct access to X.25 level 3, the facility field can be
appended with facilities specified in the
opt parameter of the
IPCCONNECT intrinsic. The values for the facilities used must follow the
X.25 recommendation.
For example, a user wants to use a facility set with packet size and
window size negotiation and wants to append the CCITT-specified DTE
facilities to that facility set. In NMMGR, the user has verified the
facility set contains packet size and window size negotiation. The
facility field generated from the facility set would contain the following
(in octal):
Facility length : %6
Packet size neg code field : %102
Packet size in : %10
Packet size out : %10
Window size net code field : %103
Window size in : %7
Window size out : %7
To add the DTE facilities, the user must specify all the bytes required
by the X.25 recommendation in the IPCCONNECT request. In this
example, to add the DTE facilities (calling address extension, called
address extension and QOS end-to-end delay) the following values must
be entered in the option field buffer (shown in octal):
CCITT-specified DTE fac marker : %17
Calling add extension code : %313
Calling add extension length : %3
Calling add extension : %5
: %5
Called add extension code : %312
Called add extension length : %3
Called add extension : %6
: %6
QOS minimum throughput : %12
QOS throughput in/out : %314
NetIPC appends this to the facility-set generated field, and updates the
“facility length”. In this example, the facility length would be %21.
When a connection is received, the user can examine the entire facility
field (see IPCRECV).