Introduction to DLPI
DLPI Services
Connection Release Service
The connection release service provides for the DLS users or the DLS provider to initiate the connection release. Connection release is an abortive operation and any data in transit (has not been delivered to the DLS user) may be discarded.
DL_DISCONNECT_REQ requests that a connection be released.
DL_DISCONNECT_IND informs the DLS user that a connection has been released. Normally, one DLS user requests disconnection and the DLS provider issues an indication of the ensuing release to the other DLS user, as illustrated by the message flow in Figure
Figure 1-20 Message Flow: DLS User-Invoked Connection Release
DL_DISCONNECT request 
DL_OK 
acknowledge
DL_DISCONNECT indication
Figure 1-21 illustrates that when two DLS users independently invoke the connection release service, neither received a
DL_DISCONNECT_IND.
Figure 1-21 Message Flow: Simultaneous DLS User Invoked Connection Release
DL_DISCONNECT request
DL_OK 
acknowledge
DL_DISCONNECT request
DL_OK acknowledge
Figure 1-22 illustrates that when the DLS provider and the local DLS user simultaneously invoke the connection release service, the remote DLS user receives a DL_DISCONNECT_IND.
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