Designing DCCP: congestion control without reliability

  • Authors:
  • Eddie Kohler;Mark Handley;Sally Floyd

  • Affiliations:
  • UCLA;University College London;ICSI Center for Internet Research

  • Venue:
  • Proceedings of the 2006 conference on Applications, technologies, architectures, and protocols for computer communications
  • Year:
  • 2006

Quantified Score

Hi-index 0.00

Visualization

Abstract

Fast-growing Internet applications like streaming media and telephony prefer timeliness to reliability, making TCP a poor fit. Unfortunately, UDP, the natural alternative, lacks congestion control. High-bandwidth UDP applications must implement congestion control themselves-a difficult task-or risk rendering congested networks unusable. We set out to ease the safe deployment of these applications by designing a congestion-controlled unreliable transport protocol. The outcome, the Datagram Congestion Control Protocol or DCCP, adds to a UDP-like foundation the minimum mechanisms necessary to support congestion control. We thought those mechanisms would resemble TCP's, but without reliability and, especially, cumulative acknowledgements, we had to reconsider almost every aspect of TCP's design. The resulting protocol sheds light on how congestion control interacts with unreliable transport, how modern network constraints impact protocol design, and how TCP's reliable bytestream semantics intertwine with its other mechanisms, including congestion control.