LISA: A Linked Slow-Start Algorithm for draft-barik-mptcp-lisa-1 Runa Barik (UiO), Simone Ferlin (SRL), Michael Welzl (UiO) Multipath TCP @96th IETF Meeting Berlin, Germany th July 16 IETF96 LISA: A Linked Slow-Start Algorithm for 1 / 16
What is new? A paper 1 published. A patch file on http://heim.ifi.uio.no/runabk/lisa/ Updated by draft-barik-mptcp-lisa-1 Presented in IETF94, Yokahama, Japan. 1 Runa Barik, Michael Welzl, Simone Ferlin and Ozgu Alay, LISA: A Linked Slow-Start Algorithm for, in IEEE ICC 16 IETF96 LISA: A Linked Slow-Start Algorithm for 2 / 16
is very simple; it is just an update to the very first slow-start of new subflows. When a new subflow joins, we find one available subflow that could give a part of its cwnd to the new subflow. If there is no subflow, assign the default values based on RFC 339 and RFC 6928. The goal is to reduce temporary aggressiveness, and losses at the end of slow-start. IETF96 LISA: A Linked Slow-Start Algorithm for 3 / 16
Outline Feedback from IETF94: Slowing down slow start will reduce retransmissions, does not work in large delay-bw environments. See graphs relating to BDP. Current parameters are unrealistic. What is now? Performance of LISA in Shared and Non-Shared Bottleneck, varying: Number of subflows RTT Bandwidth LISA behavior for a large transfer IETF96 LISA: A Linked Slow-Start Algorithm for 4 / 16
Topology Server Eth Eth1 Eth Bottleneck Link Client (a) Shared bottleneck Bottleneck Link Server Bottleneck Link (b) Non-Shared bottleneck Client IETF96 LISA: A Linked Slow-Start Algorithm for 5 / 16
Shared Bottleneck: Number of subflows 1 8 Base RTT=ms BW=5Mbps 7 8 9 (c) Mean-completion time (2 subflows) 7 7 8 9 (e) Retransmissions 2 18 1 8 BW=5Mbps Base RTT=ms 8 1 (d) Mean-completion time (4 subflows) 8 8 1 (f) Retransmissions IETF96 LISA: A Linked Slow-Start Algorithm for 6 / 16
Shared Bottleneck: RTT Base RTT=1ms BW=5Mbps 7 9 1 17 19 (a) Mean-completion time 1 8 7 9 1 17 19 (b) Retransmissions sum of cwnd 1 1 8 Transfer-size=KB.2.4.6.8 1 1.2 1.4.2.4.6.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 Time (in sec) Time (in sec) IETF96 LISA: A Linked Slow-Start Algorithm for 7 / 16 sum of cwnd 18 1 1 1 8 Transfer-size=9KB
Shared Bottleneck: RTT 2 18 1 Base RTT=ms 8 7 8 (a) Mean completion time 16 14 12 8 6 4 2 7 8 (b) Retransmissions IETF96 LISA: A Linked Slow-Start Algorithm for 8 / 16
Shared Bottleneck: Bandwidth 5 4 3 2 BW=Mbps Base RTT=ms 7 8 9 (c) Mean completion time 7 8 9 (d) Retransmissions 6 5 4 3 2 BW=45Mbps Base RTT=ms IETF96 LISA: A Linked Slow-Start Algorithm for 9 / 16 18 1 1 1 8
Non-Shared Bottleneck: RTT 1 8 Base RTT=ms BW=5Mbps 8 118 (a) Mean completion time 8 7 8 1 18 (b) Retransmissions BW=5Mbps Base RTT=ms 8 118 8 118 IETF96 LISA: A Linked Slow-Start Algorithm for / 16 2 1
Non-Shared Bottleneck: Bandwidth 5 4 Base RTT=ms 3 2 BW=35Mbps 8 118 (a) Mean completion time 9 8 7 8 1 18 (b) Retransmissions 5 4 3 2 BW=45Mbps Base RTT=ms 35 25 15 5 8 118 8 1 18 IETF96 LISA: A Linked Slow-Start Algorithm for 11 / 16
Shared Bottleneck: Large transfer R ss (in pkts) 18 1 1 1 8 Bandwidth=5Mbps 8 1 1 1 18 Base RTT (in ms) (a) Vary RTT R ss (in pkts) 2 1 Base RTT=ms 5 15 25 Bandwidth (in Mbps) (b) Vary Bandwidth Number of Retransmissions at the end of SS IETF96 LISA: A Linked Slow-Start Algorithm for 12 / 16
Non-Shared Bottleneck: Large transfer 3 3 R ss (in pkts) 2 1 Bandwidth=5Mbps R ss (in pkts) 2 1 Base RTT=ms 8 1 1 1 18 Base RTT (in ms) (a) Vary RTT 5 15 25 Bandwidth (in Mbps) (b) Vary Bandwidth Number of Retransmissions at the end of SS IETF96 LISA: A Linked Slow-Start Algorithm for 13 / 16
Thank you! IETF96 LISA: A Linked Slow-Start Algorithm for 14 / 16
LISA in Shared Bottlenck Server Eth Eth1 Bottleneck Link (a) Shared bottleneck LISA behaves less aggressive than Eth Client Retransmissions sum of cwnd 8 7 Transfer-size=5KB.1.2.3.4.5.6.7.8.9 1 LISA Time (in sec) (b) Total cwnd LISA.1.2.3.4.5.6.7.8.9 1 Time (in sec) Transfer-size=5KB IETF96 LISA: A LinkedTotal Slow-Start retransmissions Algorithm for 15 / 16
LISA in Non-Shared Bottlenck Server Bottleneck Link Bottleneck Link (a) Non-Shared bottleneck cwnd (in packets) 7 Client Retransmissions.1.2.3.4.5.6.7.8.9 1 35 25 15 Time (in sec) main flow subflow 5 LISA main flow LISA subflow.1.2.3.4.5.6.7.8.9 1 main flow subflow LISA main flow LISA subflow Transfer-size=KB Time (in sec) (b) Retransmissions IETF96 LISA: A Linked Slow-Start Algorithm for 16 / 16