Transmission Sequence Number

This term is abbreviated as TSN and is more commonly referred or known by the name of TSN in the networking world. This concept is present in the SCTP technology. SCTP stands for Stream Control Transmission Protocol. This technology SCTP is basically a transport layer protocol, as suggested by the name and it servers the same role as the TCP and UDP or Transmission Control Protocol and User Datagram Protocol. This technology was made after the release of UDP and TCP, in fact, this technology is quite recent as compared to the other two, hence, this technology has been equipped with certain features, taken or choosen from both these previous transportation protocol.

Like, this technology has the UDP feature in it that SCTP is message oriented, and the TCP feature present in this technology is that it ensures reliable in sequence transport of messages with congestion control. This technology was defined in the IETF signaling transport working group in the year 2000. This transport layer protocol is defined in the RFC 4960 and the RFC 3286 gives a detailed introduction to this protocol.

As mentioned earlier, this protocol is used as the transport protocol, however, this protocol is used in the networks where multiple connections are established and the data have to flow through these to reach the right destination. For this purpose this protocol does three things to the data packets. The first data packet is labeled with the header and the address of the destination, while the remaining data packets that come between the first data packet and the last data packet are marked with the TSN, and the last packet is market with the Acknowledgement number.

The role of this TSN is to ensure that the packets that are sent by the source remain in a particular order, as they were released and they do not get mixed up with some other data packets and are able to reach their destination. This TSN is a 32 bit sequence number that is assigned to the data packet.