DLPI Programmer's Guide

42 Chapter 1
Introduction to DLPI
DLPI Services
• The DLS provider will discard all DLSDUs submitted before the
issuing of the DL_RESET_REQ that have not been delivered to the
peer DLS user when the DLS provider issues the DL_RESET_IND.
• The DLS provider will discard all DLSDUs submitted before the
issuing of the DL_RESET_RES that have not been delivered to the
initiator of the DL_RESET_REQ when the DLS provider issues the
DL_RESET_CON.
• No DLSDU transmitted by a DLS user after the synchronization
mark in that transmitted stream will be delivered to the other DLS
user before the synchronization mark in that received stream.
The complete message flow depends on the origin of the reset, which may
be the DLS provider or either DLS user. Figure 1-23 illustrates the
message flow for a reset invoked by one DLS user.
Figure 1-23 Message Flow: DLS User-Invoked Connection Reset
Figure 1-24 illustrates the message flow for a reset invoked by both DLS
users simultaneously.
Figure 1-24 Message Flow: Simultaneous DLS User-Invoked Connection
Reset
Figure 1-25 illustrates the message flow for a reset invoked by the DLS
provider.
DL_RESET
request
DL_RESET
DL_RESET
DL_RESET
DL_OK
response
indication
acknowledge
confirm
DL_RESET
request
DL_RESET
request
DL_RESET
confirm
DL_RESET
confirm