Hi Jonathan,
Thanks for the comments. The actual proposal is to send up to double the
nominal transmit rate when there's available bandwidth, and to reduce the
rate as necessary if there isn't enough bandwidth. This doubling is to
allow fair sharing of the chokepoint bandwidth (between DCCP media apps and
TCP apps), and to avoid what appears to me to be the potential for bullying
from TCP applications that want to suck up all the bandwidth they can. It
doesn't preclude using low-rate codecs, or mean that the access link must
support the double rate for the connection to function well.
This recommendation was meant for best-effort environments, where the voice
traffic receives no special treatment, and must compete with TCP apps for
network resources. I can see how this would require a network that gave
special treatment to voice packets to provision double the capacity, though.
What about networks where there is also a lot of UDP traffic? For
example, these same networks providing voip traffic today. If I
incrementally add dccp support, it seems like I will need to increase
the provisioned capacity so I dont push out the UDP, no?