Stream Control Transmission Protocol (SCTP) is a relatively new transport layer in the IP Protocol Stack. In an LTE network, SCTP is used to provide guaranteed message delivery between the MME and eNodeB.
SCTP belongs to the SIGTRAN protocol family and has been used as the transport layer for carrying telecom signaling over IP. SCTP provides a reliable transport service that operates at message level (unlike TCP that provides a byte stream
interface with no message boundaries).
SCTP allows multiple message streams to be exchanged on a single SCTP connection. Data from multiple streams can be sent in a single SCTP message as chunks. Selective acknowledgements are supported at individual chunk level.
SCTP protocol allows dynamic configuration of the IP addresses. Similar to SS7, SCTP can be switched over from one link to another. SCTP supports a make-before-break changeover, i.e. the packet stream is moved before removing the link that needs to be taken out of service.
In this sequence diagram we will be examining some of the features of SCTP.
- SCTP Connection establishment.
- SCTP data exchange and selective acknowledgement.
- Addition of a new IP address to an SCTP connection.
- Switching over to the new IP address.
- Removing the old IP address.
- SCTP connection release