tcp - TCP/IP 是否防止数据包重播？

Question

TCP/IP 是否会阻止同一数据包的多个副本到达目的地？还是由端点决定在它上面层幂等逻辑？

如果可能，请引用 TCP/IP 规范中的特定段落。

Answer 1

从重复数据包中恢复是 TCP 堆栈的工作:

The TCP must recover from data that is damaged, lost, duplicated, or delivered out of order by the internet communication system. This is achieved by assigning a sequence number to each octet transmitted, and requiring a positive acknowledgment (ACK) from the receiving TCP. If the ACK is not received within a timeout interval, the data is retransmitted. At the receiver, the sequence numbers are used to correctly order segments that may be received out of order and to eliminate duplicates. Damage is handled by adding a checksum to each segment transmitted, checking it at the receiver, and discarding damaged segments.

-- RFC 793 - 传输控制协议(protocol)，第 1.5 节

但是，如果它们是具有新序列号的相同数据包，则不会。