Welltech Dialogic SS7 Protocols ISUP - Manual (Page 100)

Section 6 Interface to Application
ANSI operation
In ANSI, the Loop Back Acknowledgement request (LPA) message is used to
indicate that the continuity check loop has been successfully applied this
primitive is described in Section 6.5.16: Loop Back Acknowledgement
Request on page 38 .
Figure 17. Example of a Continuity Check Request Message Received (ANSI)
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RLC
RLC
CCR CCR
LPA
LPA
RLC
REL REL
ISUP
MODULE
USER
APPLICATION NETWORK