Adding Explicit Congestion Notification (ECN) Capability to TCP's SYN/ACK Packets

• Adding Explicit Congestion Notification (ECN) Capability to TCP's SYN/ACK Packets,
  A. Kuzmanovic, S. Floyd, and K.K. Ramakrishnan,
  Internet-draft draft-ietf-tcpm-ecnsyn-05.txt, work-in-progress, February 2008.
  Local copy: (text, postscript). ECN web page. Forwarded to the IESG.

• The earlier SIGCOMM paper: The Power of Explicit Congestion Notification (PDF), A. Kuzmanovic, SIGCOMM, August 2005.

• NS2, two-way TCP:
  • To enable ECN-Capability for SYN/ACK packets in two-way TCP (tcp-full) in ns-2:
    Agent/TCP/FullTcp set ecn_syn_ true
  • To have the responder wait a round-trip time if a SYN/ACK packet is ECN-marked:
    Agent/TCP/FullTcp set ecn_syn_wait_ true
  • NS2 validation tests with two-way TCP (in tcl/test):
    • To run test: ./test-all-ecn-ack synack1_fulltcp
      Guide: SYN/ACK packet dropped, FullTCP.
      The TCP initiator waits three seconds before resending the SYN packet.
    • To run test: ./test-all-ecn-ack synack2_fulltcp
      Guide: SYN/ACK packet marked, FullTCP.
      Both TCP end nodes are sending data packets. Initially, the TCP initiator sends two data packets, with a responding data packet from the TCP responder.
    • To run test: ./test-all-ecn-ack synack2a_fulltcp
      Guide: SYN/ACK packet marked, FullTCP, wait.
      With ecn_syn_wait_ set to true, the TCP responder delays in sending data packets, but it doesn't delay in sending ACK packets.
• NS2, one-way TCP:
  • To enable ECN-Capability for SYN/ACK packets in one-way TCP in ns-2:
    Agent/TCPSink set ecn_syn_ true
  • NS2 validation tests with one-way TCP (in tcl/test):
    • To run test: ./test-all-ecn-ack synack1
      Guide: SYN/ACK packet dropped.
    • To run test: ./test-all-ecn-ack synack2
      Guide: SYN/ACK packet marked.

• Simulations: The scripts for the simulations in draft-ietf-tcpm-ecnsyn will be added here by March 21.