Is sequencing a concern in Diameter

Question

It seems to me that out of order delivery is possible in Diameter even in simple networks (SCTP unordered delivery, for starters), that in more complicated networks there are even more opportunities for out of order delivery, and that overload situations might make usually small time gaps bigger.

Can anyone clarify this (is sequencing a concern, and if not then why)?

Answer 1

Yes, it is possible that requests/answers may be delivered out of order, especially when they take different paths due to network problems.
In some session based applications (Ro, DCCA), PDUs carry request number. Application level logic can use this field if sequence is important.
In cases where request/answer complete a transaction, generally order wouldn't matter. But applications can always build in additional logic.