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![SCTP socket API
• One-to-many style and one-to-one style are supported.
• Please read the API standard before programming, there
are lots of different features comparing to TCP socket.
• One-to-many server
– socket(PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP)
– bind(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr))
– setsockopt(m_fds[i].fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
– listen(sock, 2);
– sctp_recvmsg(sock, buffer, BUFFER_SIZE, NULL, 0, NULL, &flags)
– close(sock)
• One-to-many client
– socket(PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP))
– connect(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr)
– send(sock, buffer, MSG_SIZE, 0)
– close(sock)
» Refer SCTP API](https://image.slidesharecdn.com/sctpintroductions-130327012658-phpapp01/85/SCTP-introduction-28-320.jpg)
Uploaded byLi Xiong
SCTP introduction
This document provides an overview of the Stream Control Transmission Protocol (SCTP). SCTP was developed to provide reliable message transmission with built-in multi-homing and multi-streaming capabilities. It addresses some limitations of TCP and improves resistance to denial-of-service attacks. SCTP supports features like message-based communication, multi-homing for redundancy, multi-streaming for increased throughput, and reliable data transfer. It defines message and acknowledgement chunks, as well as procedures for association setup and shutdown. SCTP is supported on Linux and other operating systems and can be used as an alternative to TCP in telecommunications and other applications.
![5G Explained! A High Level Overview [Introduction]](https://cdn.slidesharecdn.com/ss_thumbnails/5gexplainedahighleveloverview-260119165306-cc137a3e-thumbnail.jpg?width=640&height=640&fit=bounds)
SCTP introduction
- 1. SCTP introduction Richard Xiong 2013/2/8
- 2. Motivations • Provide reliabletransfer without sequence maintenance. • The stream-oriented nature of TCP is often an inconvenience. SCTP provides message based transfer. • TCP is relatively vulnerable to denial-of- service attacks, such as SYN attacks. • …
- 3. History • First implementationon 1991 • submitted to IETF on 1998. RFC 4960 defines the protocol. RFC 3286 provides an introduction. (RFC2960 and RFC3309 are obsoleted). • Designed for telecom signaling transfer at first, and used on other applications • supported by Cisco, Linux, HP, Solaris, Alcatel- Lucent,… » refrence
- 4. Network layers Upper layer applications TCP UDP SCTP IP Link Layer Physical Layer
- 5. Features • Message-based • Multi-homing • Multi-stream • Reliable transfer • Robust and safety ( four way handshake ,heartbeat, three way shutdown )
- 6. Multi-homing SW HUB 1 1 10.0.0.1 Alternate Path 10.0.0.3 End-point A End-point Z 10.0.0.65 10.0.0.68 SW HUB 2 2 Primary path
- 7. Multi-stream Strm1 Strm2 Strm3 End-point SSN 1 SSN 1 SSN 1 End-point A Z Strm1 Strm2 Strm3 SSN 2 SSN 2 SSN 2 Strm1 Strm2 Strm3 SSN 3 SSN 3 SSN 3 SSN: Stream Sequence Number
- 8. Multi-stream End-point End-point A Z Strm2 Strm3 Strm1 Strm2 Strm3 SSN 2 SSN 2 SSN 1 SSN 1 SSN 1 Strm1 SSN 2 Strm1 Strm2 Strm3 SSN 3 SSN 3 SSN 3
- 9. Multi-stream End-point End-point A Z Strm2 Strm3 SSN 2 SSN 2 Strm1 Strm2 Strm3 Strm1 SSN 1 SSN 1 SSN 1 SSN 2 Strm1 Strm2 Strm3 SSN 3 SSN 3 SSN 3
- 10. Multi-stream End-point End-point A Z Strm2 Strm3 Strm2 Strm1 SSN 2 SSN 2 SSN 3 SSN 2 Strm1 Strm2 Strm3 SSN 1 SSN 1 SSN 1 Strm1 Strm3 SSN 3 SSN 3
- 11. Multi-stream End-point End-point A Z Strm2 Strm3 SSN 2 SSN 2 Strm2 Strm1 Strm1 Strm2 Strm3 SSN 3 SSN 2 SSN 1 SSN 1 SSN 1 Strm1 Strm3 SSN 3 SSN 3
- 12. Multi-stream End-point End-point A Z Strm2 Strm1 Strm1 Strm2 Strm3 SSN 3 SSN 2 SSN 1 SSN 1 SSN 1 Strm2 Strm3 Strm1 Strm3 SSN 2 SSN 2 SSN 3 SSN 3
- 13. Multi-stream End-point End-point A Z Strm3 Strm1 SSN 3 SSN 3 Strm2 Strm1 Strm1 Strm2 Strm3 SSN 3 SSN 2 SSN 1 SSN 1 SSN 1 Strm2 Strm3 SSN 2 SSN 2
- 14. Multi-stream End-point End-point A Z Strm2 Strm1 Strm1 Strm2 Strm3 SSN 3 SSN 2 SSN 1 SSN 1 SSN 1 Strm2 Strm3 SSN 2 SSN 2 Strm1 Strm3 SSN 3 SSN 3
- 15. Multi-stream End-point End-point A Z Strm1 Strm2 Strm3 Strm2 Strm1 SSN 1 SSN 1 SSN 1 SSN 3 SSN 2 Strm2 Strm3 SSN 2 SSN 2 Strm1 Strm3 SSN 3 SSN 3
- 16. Multi-stream Strm2 Strm1 End-point SSN 3 SSN 2 End-point A Z Strm1 Strm2 Strm3 SSN 1 SSN 1 SSN 1 Strm2 Strm3 SSN 2 SSN 2 Strm1 Strm3 SSN 3 SSN 3
- 17. Multi-stream End-point End-point A Z Strm1 Strm2 Strm3 SSN 1 SSN 1 SSN 1 Strm1 Strm2 Strm3 SSN 2 SSN 2 SSN 2 Strm1 Strm2 Strm3 SSN 3 SSN 3 SSN 3
- 18. Status of Association CLOSED COOKIE_WAIT COOKIE_ECHOED SHUTDOWN- ACK-SENT SHUTDOWN- RECIEVED ESTABLISHED SHUTDOWN- SENT SHUTDOWN- PENDING
- 19. SCTP messages • Data-- SACK • INIT -- INIT ACK -- COOKIE ECHO -- COOKIE ACK • Heartbeat -- Heartbeat ACK • Shutdown – Shutdown ACK -- SHUTDOWN COMPLETE • Abort
- 20. Setting Up Endpoint A Endpoint Z CLOSED CLOSED INIT 1 COOKIE-WAIT INIT-ACK COOKIE-ECHO * COOKIE-ECHOED 2 * COOKIE-ACK ESTABLISHED ESTABLISHED * -- User data can be attached
- 21.
- 22. Close Endpoint A Endpoint Z Shutdown from application SHUTDOWN-PENDING Transfer remaining data SHUTDOWN SHUTDOWN-SENT SHUTDOWN-RECEIVED SHUTDOWN ACK SHUTDOWN-ACK-SENT SHUTDOWN COMPLETE CLOSED CLOSED
- 23. Packet Structure Refer to wikipedia
- 24.
- 25.
- 26. Fault management • Primary/alternatePath detection • Resend mechanism • Congestion control (RFC2581)
- 27. Installation on Linux(lksctp) • Check if SCTP is installed – grep SCTP /proc/net/protocols – checksctp • Download code from http://lksctp.sourceforge.net/
- 28. SCTP socket API •One-to-many style and one-to-one style are supported. • Please read the API standard before programming, there are lots of different features comparing to TCP socket. • One-to-many server – socket(PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP) – bind(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr)) – setsockopt(m_fds[i].fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)); – listen(sock, 2); – sctp_recvmsg(sock, buffer, BUFFER_SIZE, NULL, 0, NULL, &flags) – close(sock) • One-to-many client – socket(PF_INET, SOCK_SEQPACKET, IPPROTO_SCTP)) – connect(sock, (struct sockaddr*)&addr, sizeof(struct sockaddr) – send(sock, buffer, MSG_SIZE, 0) – close(sock) » Refer SCTP API
- 29. Others • shortages – http://datatag.web.cern.ch/datatag/WP3/sctp/tests. • New research – Concurrent multipath transfer
- 30. Reference • http://en.wikipedia.org/wiki/Stream_Control_Transmission_Pro • RFC4960 • RFC 2581 • http://www.youtube.com/watch?v=dIPwN-z6lVA • http://www.sctp.org/ • http://www.sourceforge.net/projects/lksctp • http://linux.die.net/man/7/sctp • http://www.ibm.com/developerworks/library/l-sctp/ • http://www.linuxjournal.com/article/9784
- 31.
Editor's Notes
- #21 1: generate cookie by MAC, timestamp and lifespan and … Don’t create TCB to avoid DOS 2: compare the cookie received with the cookie send on INIT-ACK