H-TCP – Congestion Control for High Delay-Bandwidth Product Networks

Internet Drafts
Internet draft draft-leith-tcp-htcp-00.txt
Slides from IETF63 meeting, Paris.

  • Original linux patches implementing HTCP and improving slow path efficiency in network stack:
    2.4.23, 2.6.6
    Note: H-TCP maintained as part of standard Linux kernel distribution from 2.6.13 onwards.
  • H-TCP is available in the Linux kernel as of 2.6.13, but an error was introduced that was not fixed until 2.6.16. If you are conducting tests of H-TCP, please use Linux kernel version 2.6.16 and above or contact us for the appropriate patch to the previous versions.
  • H-TCP is now available in FreeBSD. Implemented at Swinburne with funding from Cisco. See here.
  • ns implementation of HTCP

Experimental testing
  • Early tests were carried out at SLAC in October 2003 comparing HTCP, FAST, Highspeed TCP, Scalable and some other proposals. Unfortunately different network stack implementations were used for each congestion control algorithm, with numerous specific changes in most stacks (not HTCP at that time) to improve SACK processing efficiency (which has known problems, see our report, also Tom Dunigan’s page) and other substantive changes. Comparisons of protocol performance is therefore not possible in these tests.
  • The group at Caltech briefly report on HTCP tests in their GridNets 2004 paper.
  • Injong Rhee at North Carolina have carried out DummyNet tests here.
  • Results of 2007 evaluation tests at UCL and HI are available here.
  • Results of extensive tests at NIST in 2009 are here
  • Results of 2009 evaluation tests over home DSL links at Swinburne to appear at Networking 2009.