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Computer Networking Research Laboratory

Dept. of Electrical & Computer Engineering, Colorado State University

Packet Reordering


With increasing link speeds and increased parallelism within routers, packet reordering will be more widespread over the Internet. The definition of "percentage out-of-order" metric is vague and ambiguous and in addition, the measure is incapable of characterizing and evaluating the packet-reordering problem. At CNRL, we have proposed two metrics for reordering, "Reorder Density" (RD) and "Reorder Buffer-occupancy Density" (RBD). In addition, we also characterize reordering introduced by a network in the form of "Reorder Response."
For complete description of RD and RBD and other useful details, follow these links: 

Team members

  • Abhijit A. Bare
  • Tarun Banka
  • Bin Ye
  • Ramanathan Sivakumar


  1. N. M. Piratla,  A. P. Jayasumana, A. A. Bare, and T. Banka, "Reorder Buffer-Occupancy Density and its Application for Evaluation of Packet Reordering," Computer Communications, vol. 30/9, 2007, pp. 1980-1993,
  2. A. A. Bare, A. P. Jayasumana, and N.M. Piratla, "On Growth of Parallelism within Routers and Its Impact on Packet Reordering," In Proc. 15th IEEE Workshop on Local and Metropolitan Area Networks, Princeton NJ, June 2007, pp. 145-150.
  3. N. M. Piratla and A. P. Jayasumana, "Metrics for Packet Reordering - A Comparative Analysis," International Journal of Communication Systems, Volume 21, Issue 1, Jan. 2007, pp. 99-113
  4. B. Ye, A. P. Jayasumana, and N. Piratla, "On Monitoring of End-to-End Packet Reordering over the Internet," In Proc. Int. Conf. on Networking and Services (ICNS'06), Santa Clara, CA, July 2006.
  5. N.M. Piratla and A. P. Jayasumana, "Reordering of Packets due to Multipath Forwarding - An Analysis," In Proc. IEEE Inernational Conference on Communications (ICC 2006), Istanbul, Turkey, June 2006.
  6. N. Piratla, A. P. Jayasumana, and A. Bare "A Comparative Analysis of Packet Reordering Metrics," Presented at First International Conference on Communication System Software and Middleware (COMSWARE 2006), New Delhi, India, Jan. 2006.
  7. Piratla, A.P. Jayasumana, and T. Banka, "On Reorder Density and its Application to Characterization of Packet Reordering," In Proc. 30th IEEE Conference on Local Computer Networks, Sydney, Australia,  November 2005, pp. 156-163.

IETF Presentations