T2 Allowed Acknowledgements/Errors

Ian, David,

We've discussed endless loops but I'm not sure we have actually come to
agreement.  May I suggest we put this on the next Con Call agenda?

Should we specifically not allow?
1.  Ack on Ack
2. DeliveryReceipt on DeliveryReceipt
3. Error on Error
4. DeliveryReceipt on Ack
5. Ack on DeliveryReceipt
6. DeliveryReceipt on Error
7. Error on DeliveryReceipt
8. Error on Ack
9. Ack on Error

I suggest we should not allow 1-6.  Item 7 is probably OK.  Items 8 and 9 are
mutually exclusive, i.e. we can have either but not both (probably 8).  Anyone
else have an opinion?

Regards,

David Fischer
Drummond Group