DDSIRTP2 — Interpreting Liveliness Heartbeats

Source:
Real-Time Innovations, Inc. (Ken Brophy, ken@rti.com)
Summary:
For better performance and simpler reliability, a liveliness heartbeat should be allowed to be a liveliness-only message without heartbeat semantics. As subclassed from a heartbeat, a liveliness heartbeat may trigger an ACKNACK response; to be a liveliness-only message, no ACKNACKs should be triggered. To enable this, setting the final flag should not trigger ACKNACKs.

Resolution:
A liveliness heartbeat with final-flag set must not trigger any ACKNACKs.

Revised Text:
Append to 8.4.2.3.2:

The response is not required when a liveliness HEARTBEAT has both liveliness and final flags set to indicate it is a liveliness-only message.

Revise statechart 8.24:

Revise Table 8.76 with revised transition:

Transition state event next state
T2 waiting HEARTBEAT message is received if (HB.FinalFlag==NOT_SET)then must_send_ackelse if (HB.LivelinessFlag == NOT_SET)then may_send_ackelse waiting

see above