DDS — Additional_qos_LIFESPAN Issue

Issue# 2100 Additional_qos_LIFESPAN Issue [Boeing SOSCOE] ? The LIFESPAN Qos Policy that prevents “stale” data from being delivered to receiving applications. ? The LIFESPAN defines a time period for which the data should live. If a message cannot be delivered before the specified time period, the message is dropped. This value is expressed in time units, it should not be confused with a network-level Time-To-Live (TTL), that could be set on network connections which is expressed in number of hops. ? LIFESPAN is specified as a “span” that is a time interval measured from the time the data is written. ? LIFESPAN should be mutable. ? LIFESPAN needs to be specified only in the writer side. ? Note that this QoS assumes that the sender and receiving applications have their clocks sufficiently synchronized. ? The filtering could be done on the sending side, on the receiving side, or both. It would be an implementation decision that would only affect performance but would otherwise not be observable by the application. ? If data is dropped because the LIFESPAN value expires, Reliable and Transactional QoS would still require the writer to be notified of the failure to deliver. Proposal [Boeing SOSCOE] ? Introduce the LIFESPAN Qos.

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