Design and simulation on improving SCTP performance based on a collaborative approach
Li Lu · 2006
Stream control transmission protocol(SCTP) is a transport layer protocol proposed by IETF.It could be used for transport tasks on the IP-based network.SCTP was designed for wired networks as well as the well-known transport layer protocol TCP.The characteristics of wireless networks including high bit-error-rate and large delay variation were not considered in SCTP.SCTP was improved by introducing the collaboration with 802.11 MAC layer which made SCTP detect the packet losses caused by wireless bit error sensitively.When wireless loss occurred,the data link layer would retransmit the lost frame. If the number of transmission attempts reached the threshold,the frame would be discarded.And the data link layer would create an error report chunk for the upper layer-SCTP.SCTP could collect the information before SACK chunk returned or timeout process began.So SCTP modified the threshold of reduplicate SACKs which could trigger the fast retransmit phase which could deal with the situation using the recovery algorithm to avoid unnecessary shrinkage of the congestion window.Simulation results show that improved SCTP achieves evidently much better performance and larger goodput in heterogeneous networks.And the improved protocol also does well in fairness and friendliness compared with the original protocol.