问题描述
我最近看了一本书 "UNIX Network Programming, Vol. 1"Richards Stevens 和我发现除了 TCP 和 UDP 之外还有第三个传输层标准:SCTP.
I recently checked out the book "UNIX Network Programming, Vol. 1" by Richards Stevens and I found that there is a third transport layer standard besides TCP and UDP: SCTP.
总结:SCTP 是一种传输级协议，它像 UDP 一样是消息驱动的，但像 TCP 一样可靠.这是 来自 IBM DeveloperWorks 的简短介绍.
Summary: SCTP is a transport-level protocol that is message-driven like UDP, but reliable like TCP. Here is a short introduction from IBM DeveloperWorks.
老实说，我以前从未听说过 SCTP.我不记得在任何网络书籍中读到过它，或者在我参加的课程中听说过它.阅读提到 SCTP 的其他 stackoverflow 问题表明我并不孤单.
Honestly, I have never heard of SCTP before. I can't remember reading about it in any networking books or hearing about it in classes I had taken. Reading other stackoverflow questions that mentions SCTP suggests that I'm not alone with this lack of knowledge.
为什么 SCTP 如此不为人知?为什么很少使用?
推荐答案
事实上，SCTP 主要用于电信领域.传统上，电信交换机使用 SS7(7 号信令系统)来互连电信网络中的不同实体.例如——电信运营商的用户数据库(HLR)，有交换机(MSC)，用户也连接(MSC).
Indeed, SCTP is used mostly in the telecom area. Traditionally, telecom switches use SS7 (Signaling System No. 7) to interconnect different entities in the telecom network. For example - the telecom provider's subscriber data base(HLR), with a switch (MSC), the subscriber is connected too (MSC).
电信领域正在向更高的速度和更可达的环境发展.其中一项变化是用一些更优雅、快速和灵活的基于 IP 的协议取代 SS7 协议.
The telecom area is moving to higher speeds and more reachable environment. One of these changes is to replace SS7 protocol by some more elegant, fast and flexible IP-based protocol.
电信领域非常保守.SS7 网络已经在这里使用了几十年.这是一个非常可靠和封闭的网络.这意味着普通用户无法访问它.
The telecom area is very conservative. The SS7 network has been used here for decades. It is very a reliable and closed network. This means a regular user has no access to it.
相比之下，IP 网络是开放且不可靠的，如果电信至少不能处理 SS7 处理的负载，则它不会转换到 IP 网络.这就是开发 SCTP 的原因.它尝试:
The IP network, in contrast, is open and not reliable, and telecoms will not convert to it if it won't handle at least the load that SS7 handles. This is why SCTP was developed. It tries:
- 模仿 SS7 网络几十年来积累的所有优势.
- 创建一个在速度、安全性和冗余方面比 TCP 更好的面向连接的协议
最新版本的 Linux 已经支持 SCTP.
The latest releases of Linux already have SCTP support.
这篇关于为什么 SCTP 很少使用/不为人知的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！