SCTP不是很为人所知，也不是经常使用/部署，因为:

Widespread: Not widely integrated in TCP/IP stacks (in 2013: still missing natively in latest Mac OSX and Windows. 2020 update: still not in Windows nor Mac OS X) Libraries: Few high level bindings in easy to use languages (Disclaimer: i'm maintainer of pysctp, SCTP easy stack support for Python) NAT: Doesn't cross NAT very well/at all (less than 1% internet home & enterprise routers do NAT on SCTP). Popularity: No general public app use it Programming paradigm: it changed a bit: it's still a socket, but you can connect many hosts to many hosts (multihoming), datagram is ordered and reliable, erc... Complexity: SCTP stack is complex to implement (due to above) Competition: Multipath TCP is coming and should address multihoming needs / capabilities so people refrain from implementing SCTP if possible, waiting for MTCP Niche: Needs SCTP fills are very peculiar (ordered reliable datagrams, multistream) and not needed by much applications Security: SCTP evades security controls (some firewalls, most IDSes, all DLPs, does not appear on netstat except CentOS/Redhat/Fedora...) Audit-ability: Something like 3 companies in the world routinely do audits of SCTP security (Disclaimer: I work in one of them) Learning curve: Not much toolchain to play with SCTP (check the excellent withsctp that combines nicely with netcat or use socat, 2020 edit: nmap supports it for a few years now ) Under the hood: Used mostly in telecom and everytime you send SMS, start surfing the net on your mobile or make phone calls, you're often triggering messages that flow over SCTP (SIGTRAN/SS7 with GSM/UMTS, Diameter with LTE/IMS/RCS, S1AP/X2AP with LTE), so you actually use it a lot but you never know about it ;-) 2020 edit: it's being removed from the core 5G network (no more Diameter, HTTP/2 instead) and will be only used in the 5G radio access network between antennas and core.

我们中的许多人很快就会使用SCTP，因为WebRTC数据通道使用它在UDP之上创建一个类似tcp的可靠层——SCTP over DTLS over UDP: https://datatracker.ietf.org/doc/html/draft-ietf-rtcweb-data-channel-13#section-6

SCTP需要在应用程序中进行更多的设计，以便更好地利用它。它比TCP有更多的选择，类似socket的API是后来才出现的，而且它很年轻。然而，我认为大多数花时间理解它的人(并且知道TCP的缺点)都很欣赏它——这是一个设计良好的协议，建立在我们对TCP和UDP大约30年的知识之上。

其中一个需要思考的方面是流。流提供了(通常，我认为您可以关闭它)它们之间的顺序保证(很像TCP连接)，但是每个SCTP连接可以有多个流。如果您的应用程序的数据可以通过多个流发送，那么您就可以避免由于一个错误放置的数据包而导致的接收端阻塞。有效地，不同的对话可以在同一个连接上进行，而不会相互影响。

另一个有用的附加功能是多归属支持——一个连接可以跨两端的多个接口，它可以处理故障。您可以在TCP中模拟这一点，但是是在应用层。

正确的链接心跳是任何使用TCP进行非瞬态连接的应用程序实现的第一件事，它是免费的。

我个人对SCTP的总结是，它没有做任何其他方式(在TCP或UDP中)在大量应用程序支持下不能做的事情。它所提供的是不必自己(糟糕地)实现代码的能力。

供参考，SCTP是强制支持的直径(cf RADIUS下一代)。参见RFC 3588

   Diameter clients MUST support either TCP or SCTP, while agents and
   servers MUST support both.  Future versions of this specification MAY
   mandate that clients support SCTP.

Sctp诞生得太晚了，对于很多情况，TCP已经足够了。

此外，据我所知，它的大部分使用是在电信领域。

我们现在已经在几个应用程序中部署了SCTP，并且在各种家用路由器中遇到了SCTP支持的重大问题。它们不能正确地处理SCTP。我认为这主要是一个性能问题(SCTP协议规范要求重新计算整个数据包的校验和，而不仅仅是报头)。

和许多其他有前途的协议一样，SCTP在D-link和Netgear修复它们坏掉的NAT盒子之前已经不幸地死在水里了。

SCTP不是很为人所知，也不是经常使用/部署，因为:

Widespread: Not widely integrated in TCP/IP stacks (in 2013: still missing natively in latest Mac OSX and Windows. 2020 update: still not in Windows nor Mac OS X) Libraries: Few high level bindings in easy to use languages (Disclaimer: i'm maintainer of pysctp, SCTP easy stack support for Python) NAT: Doesn't cross NAT very well/at all (less than 1% internet home & enterprise routers do NAT on SCTP). Popularity: No general public app use it Programming paradigm: it changed a bit: it's still a socket, but you can connect many hosts to many hosts (multihoming), datagram is ordered and reliable, erc... Complexity: SCTP stack is complex to implement (due to above) Competition: Multipath TCP is coming and should address multihoming needs / capabilities so people refrain from implementing SCTP if possible, waiting for MTCP Niche: Needs SCTP fills are very peculiar (ordered reliable datagrams, multistream) and not needed by much applications Security: SCTP evades security controls (some firewalls, most IDSes, all DLPs, does not appear on netstat except CentOS/Redhat/Fedora...) Audit-ability: Something like 3 companies in the world routinely do audits of SCTP security (Disclaimer: I work in one of them) Learning curve: Not much toolchain to play with SCTP (check the excellent withsctp that combines nicely with netcat or use socat, 2020 edit: nmap supports it for a few years now ) Under the hood: Used mostly in telecom and everytime you send SMS, start surfing the net on your mobile or make phone calls, you're often triggering messages that flow over SCTP (SIGTRAN/SS7 with GSM/UMTS, Diameter with LTE/IMS/RCS, S1AP/X2AP with LTE), so you actually use it a lot but you never know about it ;-) 2020 edit: it's being removed from the core 5G network (no more Diameter, HTTP/2 instead) and will be only used in the 5G radio access network between antennas and core.