ABSTRACT

Stream Control Transmission Protocol (SCTP) is a transport layer protocol, which is efficient, reliable, and connection oriented as compared to Transmission Control Protocol (TCP) and User Datagram Protocol (UDP). Additionally, SCTP has few more innovative features that are multihoming, multistreaming and unordered delivery. With multihoming, SCTP establishes multiple paths between a sender and receiver. However, it only uses the primary path for data transmission and secondary path (or paths) for fault tolerance. Concurrent Multipath Transfer extension of SCTP (CMT­ SCTP) allows a sender to simultaneously transmit data over multiple paths, which increase the overall transmission throughput.

Due to simultaneous data transfer using CMT-SCTP, the unordered data packets arrival is very common. The receiver has to wait until the missing data packets arrive, which cause the performance degradation while using CMT-SCTP. In order to reduce the transmission delay at the receiver, CMT-SCTP uses intelligent retransmi ssion polices to immediately retransmit the missing packets. The retransmission policies used by CMT-SCTP are RTX-SAME, RTX-ASAP , RTX-SSTHRESH , RTX­
LOSSRATE and RTX-CWND. The main objective of this thesis is the performance analysis of the retransmission policies. The policies RTX-SAME and RTX-ASAP are no more used with CMT-SCTP. So, this thesis evaluates RTX-SSTHRESH , RTX­ LOSSRATE and RTX-CWND. The simulations are performed on the Network Simulator 2. In the simulations with various scenarios and parameters, it is observed that the RTX-LOSSRATE is a suitable policy.


Keywords: CMT, CMT-SCTP Retransmission Policies, SCTP.