Imported from previous forum
The current spefication says that TestRequest messages should not be resent as part of resend-request processing,and instead be gap-filled.
This can cause an issue when using the recommended recovery method…
"Note: it is imperative that the receiving application process messages in sequence order, e.g. if message number 7 is missed and 8-9 received, the application should ignore 8 and 9 and ask for a resend of 7-9, or, preferably, 7-0 (0 represents infinity). This latter approach is strongly recommended to recover from out of sequence conditions as it allows for faster recovery in the presence of certain race conditions when both sides are simultaneously attempting to recover a gap.”
When this rules is applied a TestRequest received that is > next expected seq num will cause a Resend Request… and the result of which will not resend the TestRequest message and therefore not generate a HB response to the TR.
It is not clear what should happen in this unlikely event… but system testing forces us to test these circumstances.
How do other people deal with this scenario?
Clive