An Adaptive Optimized RTO Algorithm for Multi-Homed Wireless Environments

As a transport layer protocol SCTP uses end to end metrics, such as Retransmission Time Out (RTO), to manage mobility handover. The authors' investigation illustrates that Wireless LAN (WLAN) mobility causes continuously increased Round Trip Times (RTT) resulting from 802.11 MAC retransmissions, regardless of the service specified by upper layers. They present scenarios where the current understanding of SCTP switchover aggressiveness is invalid; spurious failovers together with excessive RTO result in new forms of receiver buffer blocking communication failure. Given wireless mobility performance issues, together with the ambiguity of end to end metrics, they propose an Adaptive Optimized RTO algorithm for wireless Access Networks (AORAN) which uses local as well as end to end metrics to manage mobility.