Can a host reassemble an IP datagram?

Question

Computer networks

I found this interesting exercise from a presentation on the topic of the transport layer: "Can the receiver assemble an IP datagram from these four fragments from the same headers?"

Answer 1

Fragmented packages have an ID field specifically for identifying and separating fragments from different packages. It, in general, should be unique for each individual source package in the source-dest-proto set, but there is a BUT.
Previously, RFC 1122(791) stated that the OS MAY allow high-level protocols to keep the same ID for retransmitted copies of packets.

RFC 1122 states in Section 3.2.1.5 ("Identification: RFC 791
Section 3.2") that:
When sending an identical copy of an earlier datagram, a host MAY
optionally retain the same Identification field in the copy.

However, RFC 6864 forbids this behavior:

o The IPv4 ID field is no longer permitted to be used for duplicate
detection. This applies to both atomic and non-atomic datagrams.
o Retransmitted non-atomic IPv4 datagrams are no longer permitted to
reuse the ID value.

Taking into account the above, as well as the fact that each vendor reads the RFC selectively and in a way that is cheaper for him, the answer to the question is how lucky , depending on the software manufacturer of the sender host and / or intermediate hosts (the one who will perform the initial fragmentation ).