John Heffner

Note: I am no longer at PSC. You can contact me at



  • J. Heffner, M. Mathis, B. Chandler, "IPv4 Reassembly Errors at High Data Rates," RFC 4963, July 2007. [TXT]
  • M. Mathis, J. Heffner, R. Raghunarayan, "TCP Extended Statistics MIB," RFC 4898, May 2007. [TXT]
  • M. Mathis, J. Heffner, "Packetization Layer Path MTU Discovery," RFC 4821, March 2007. [TXT]
  • D. Leith, R. Shorten, G. McCullagh, J. Heffner, L. Dunn, F. Baker, "Delay-based AIMD congestion control," PFLDnet, February 2007. [PDF]
  • J. Heffner, "Qsockets," PSC tech report, December 2004. [PDF]
  • M. Mathis, J. Heffner and R. Reddy, "Web100: Extended TCP Instrumentation for Research, Education and Diagnosis," ACM Computer Communications Review, Vol 33, Num 3, July 2003. [PDF]
  • J. Heffner, "High Bandwidth TCP Queuing," CMU Senior Thesis, Spring 2002. [PS] [PDF]


  • Fragmentation Considered Very Harmful, IETF 66 (July 2006) [PDF]
  • Path MTU Discovery Progress Update, IETF 64 (November 2005) [PDF]
  • PMTUD Implementor's Report, IETF 62 (March 2005) [PDF]
  • Internet Security and Cryptography (April 2004) [PDF]
  • The PSC Application Gateway (February 2004) [PDF]
  • Autotuning in Web100. (February 2003) [PDF]
  • Autotuning in Web100. (August 2002) [PDF]
  • A final presentation on my senior thesis. (May 2002) [PDF]