Hello, my first participation here. I started working with FIX this week.
I am reading the FIX 4.4 specification Volume 2, page 3, and in the introduction, he says:
FIX was written to be independent of any specific communications protocol (X.25, asynch, TCP/IP, etc.) or physical
medium (copper, fiber, satellite, etc.) chosen for electronic data delivery. It should be noted that if an “unreliable”
or non-stream protocol is used, the Logon, Logout, and ResendRequest message processing is particularly
susceptible to unordered delivery and/or message loss.
but in the FIX MESSAGE DELIVERY >> Ordered Message Processing, he says:
The FIX protocol assumes complete ordered delivery of messages between parties.
Does not this sound a little contradictory?
Because FIX “was written to be independent of any specific communications”, it is natural to conclude that it works with unordered message too.