What is a characteristic of packet delivery in TCP?

In TCP (Transmission Control Protocol), one key characteristic is that packets may arrive out of order due to the nature of how data is transmitted over networks. However, TCP is designed to handle this by providing mechanisms for reassembling the packets in the correct order at the destination. This is achieved through the use of sequence numbers assigned to each packet, which allow the receiving end to reorder the packets as they arrive.

The ability to reassemble packets that have arrived out of order is essential for maintaining data integrity and ensuring that the original message is reconstructed correctly, even if the underlying network does not guarantee the order of packet delivery. TCP also includes error detection and retransmission of lost packets, adding to its reliability.

Other options suggest characteristics that do not accurately reflect how TCP operates. For example, it is not necessary for all packets to arrive simultaneously for communication to be successful, nor does TCP support the notion that no packets can be delivered simultaneously. Furthermore, the idea that every packet will arrive without needing to be reordered contradicts the very nature of how packet-switched networks function, which is fundamental to TCP's design.