Message Validation
A message Mp(Pi,Pj) sent between detection points Dk-2 (Pi) and Dk-1 (Pi) to process Pj, can be validated if,
- no error is detected before Dk (Pi) .
- all the messages received before Mp(Pi,Pj) have been validated. That is, if there is no message dependency.
Once a message to a process Pj has been validated, any error detection in Pi need not rollback Pj.