HP X.25/9000 Programmer's Guide

Chapter 6 99
Extended Features
Using Fast Select
which are discussed individually in the next three subsections.
Clearing a fast select call immediately
If the server detects that it cannot handle the fast select call for any
reason, it can clear the circuit immediately. The steps for clearing the
circuit are described below and in Table 6-2, “Clearing a Fast Select Call
Immediately.” The steps shown in Table 6-1, “Steps for Fast Select,” are
assumed to already have occurred.
Step 1. The server transmits the CLEAR REQUEST packet.
Step 2. The client receives the CLEAR INDICATION packet and takes
appropriate actions.
Transmitting a CLEAR Packet With User Data
The server can respond to a fast select call by sending a CLEAR
REQUEST packet that contains a user data field. The steps for this are
described below and shown in Table 6-3, “Sending Clear User Data for a
Fast Select.” The steps shown in Table 6-1, “Steps for Fast Select,” are
assumed to already have occurred.
Step 1. The server writes the user data field with information appropriate to
respond to the fast select call.
Step 2. The server transmits the CLEAR REQUEST packet.
Step 3. The client receives the CLEAR INDICATION packet and takes
Table 6-2 Clearing a Fast Select Call Immediately
Server Events X.25 Events Client Events
1. close() CLEAR
REQUEST
packet
transmitted
No event
2. No event CLEAR
INDICATION
packet received
connect() returns -1
(ECONNREFUSED)
36960-90061.bk Page 99 Friday, November 10, 2000 3:42 PM