Is TCP Guaranteed to arrive in order?

Question

If I send two TCP messages, do I need to handle the case where the latter arrives before the former? Or is it guaranteed to arrive in the order I send it? I assume that this is

Answer 1

TCP "guarantees" that a receiver will receive the reconstituted stream of bytes as it was originally sent by the sender. However, between the TCP send/receive endpoints (i.e., the physical network), the data can be received out of order, it can be fragmented, it can be corrupted, and it can even be lost. TCP accounts for these problems using a handshake mechanism that causes bad packets to be retransmitted. The TCP stack on the receiver places these packets in the order in which they were transmitted so that when you read from your TCP socket, you are receive the data as it was originally sent.

When you call the doRead method in Twisted, the data is read from the socket up to the size of the buffer. This data may represent a single message, a partial message, or multiple messages. It is up to you to extract the messages from the buffer, but you are guaranteed that the bytes are in their transmitted order at this point.

Sorry for muddying the waters with my earlier post...