DLPI Programmer's Guide

Chapter 1 37
Introduction to DLPI
DLPI Services
Figure 1-13 Message Flow: Token Retrieval
In the typical connection establishment scenario, the called DLS user
processes one connect indication at a time, accepting the connection on
another stream. Once the user responds to the current connect
indication, the next connect indication (if any) can be processed. DLPI
also enables the called DLS user to multi-thread incoming connect
indications. The user can receive multiple connect indications before
responding to any of them. This enables the DLS user to establish
priority schemes on incoming connect requests.
Connection Establishment Rejection. In certain situations, the
connection establishment request cannot be completed. The following
describes the occasions under which DL_DISCONNECT_REQ and
DL_DISCONNECT_IND primitives will flow during connection
establishment, causing the connect request to be aborted.
Figure 1-14 illustrates the situation where the called DLS user chooses
to reject the connect request by issuing DL_DISCONNECT_REQ instead
of DL_CONNECT_RES.
Figure 1-14 Message Flow: Called DLS User Rejection of Connection
Establishment Attempt
Figure 1-15 illustrates the situation where the DLS provider rejects a
connect request for lack of resources or other reasons. The DLS provider
sends DL_DISCONNECT_IND in response to DL_CONNECT_REQ.
DL_TOKEN
request
DL_TOKEN
acknowledge
DL_CONNECT
request
DL_DISCONNECT
indication
DL_CONNECT
DL_DISCONNECT
DL_OK
request
indication
acknowledge