java - Bittorrent 协议(protocol)中的 KeepAlive 消息

Question

我在 Internet 上的任何地方都找不到这个问题的答案。我想知道当您收到关于 bittorrent 协议(protocol)的保持 Activity 消息时会发生什么？我们应该发回保持 Activity 消息吗？

Answer 1

来自Unofficial BitTorrent Specification :

keep-alive: <len=0000>

The keep-alive message is a message with zero bytes, specified with the length prefix set to zero. There is no message ID and no payload. Peers may close a connection if they receive no messages (keep-alive or any other message) for a certain period of time, so a keep-alive message must be sent to maintain the connection alive if no command have been sent for a given amount of time. This amount of time is generally two minutes.

我不是 BitTorrent 专家，但基于此以及我确实拥有的网络协议(protocol)知识，这听起来像是您问题的答案

are we suppose to send a keep alive message back?

是没有。至于

what happens when you receive a keep alive message?

好吧，没什么 — 重要的是当您在提到的“给定时间量”后没有收到保持 Activity (或任何其他)消息时会发生什么。在 BitTorrent 实现中，接收保持 Activity 消息可能会重置计时器，或更新“收到的最后一条消息”时间戳。