This paper considers the potentially negative impacts of an increasing depl
oyment of non-congestion-controlled best-effort traffic on the Internet,(1)
These negative impacts range from extreme unfairness against competing TCP
traffic to the potential for congestion collapse. To promote the inclusion
of end-to-end congestion control in the design of future protocols using b
est-effort traffic, we argue that router mechanisms are needed to identify
and restrict the bandwidth of selected high-bandwidth best-effort flows in
times of congestion, The paper discusses several general approaches for ide
ntifying those flows suitable for bandwidth regulation. These approaches ar
e to identify a high-bandwidth flow in times of congestion as unresponsive,
"not TCP-friendly," or simply using disproportionate bandwidth. A flow tha
t is not "TCP-friendly" is one whose long-term arrival rate exceeds that of
any conformant TCP in the same circumstances. An unresponsive flow is one
failing to reduce its offered load at a router in response to an increased
packet drop rate, and a disproportionate-bandwidth flow is one that uses co
nsiderably more bandwidth than other flows in a time of congestion.