HP X.25/9000 Programmer's Guide

90 Chapter6
Extended Features
Using Facilities
Flow control negotiation, throughput class negotiation, and fast
select/reverse charging are subject to X.25 configuration constraints.
Some network providers also place further constraints on the facilities
that may be used.
The facilities supported for ioctl(X25_RD_FACILITIES) are those
described in the CCITT X.25 Recommendation (1988). These include:
• Flow Control Parameter Negotiation (Packet Size and Window
Size) – When a flow control parameter negotiation facility is received
after the packet layer has finished the negotiation, the values are
such that no further negotiation can take place. The facilities are not
available with ioctl(X25_RD_FACILITIES). For example, 0x430302
with a configured window size of 2 2 is not reported by ioctl since
the final values are 2 and 2, which is the Standard default.
• Closed User Group Selection – When either a closed user group
selection basic or extended format, or a closed user group with
outgoing access basic or extended format facility is received, it is
always reported as a closed user group selection extended format.
• Transit Delay Selection – There is no way to know if the transit
delay selection is received.
• End-to-end Transit Delay Selection – The cumulative end-to-end
transit delay, as well as the maximum acceptable end-to-end transit
delay, is forwarded. The requested end-to-end transit delay is not
available and is replaced with the unknown transit delay (0xffff).
Syntax for ioctl(X25_RD_FACILITIES)
The ioctl(X25_RD_FACILITIEs) and its parameters are described
below.
#include <x25/x25ioctls.h>
#include <x25/x25str.h>
/* define X25_MAX_FACILITIES_LEN 109
* struct x25_facilities {
* u_char x25_fac_len; /* length of facilities field */
* u_char x25_fac[X25_MAX_FACILITIES_LEN]
* /* facilities field, exactly as in packet */
* }
*/
int err;
int sd;
struct x25_facilities fac_data;
err = ioctl(sd, X25_RD_FACILITIES, &fac_data);
36960-90061.bk Page 90 Friday, November 10, 2000 3:42 PM