XMPP如何在没有任何中间跳的情况下在两个不同服务器(不同域)之间传输消息？

Question

我的团队想要建立一个聊天应用，所以我们正在研究所有可用的技术在我们的武器库。我很关心XMPP。所以我正在读奥赖利的"XMPP:权威指南“，我偶然发现了这些台词，我引用

In XMPP, messages are delivered as fast as possible over the network. Let’s say that Alice sends a message from her new account on the wonderland.lit server to her sister on the realworld.lit server. Her client effectively “uploads” the message to wonderland.lit by pushing a message stanza over a client-to-server XML stream. The wonderland.lit server then stamps a from address on the stanza and checks the to ad- dress in order to see how the stanza needs to be handled (without performing any deep packet inspection or XML parsing, since that would eat into the delivery time). Seeing that the message stanza is bound for the realworld.lit server, the wonderland.lit server then immediately routes the message to realworld.lit over a server-to-server XML stream (with no intermediate hops).第45页

Like email, but unlike the Web, XMPP systems involve a great deal of inter-domain connections. However, when you send an XMPP message to one of your contacts at a different domain, your client connects to your “home” server, which then connects directly to your contact’s server without intermediate hops (see Figure 2-4).第13页

谁能让我明白怎么可能没有中间跳(不像电子邮件)。

Answer 1

电子邮件(SMTP)也没有中间跳.我假设您将应用程序OSI层( XMPP、SMTP等)与网络层(IP)混淆。