[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [dccp] draft-ietf-dccp-tfrc-voip-04.txt



Sally,

On 30 Jan 2006, at 19:31, Sally Floyd wrote:
...
The text in RFC 3448 referring to TFRC-PS is:

TFRC is designed for applications that use a fixed packet size, and
vary their sending rate in packets per second in response to
congestion. Some audio applications require a fixed interval of
time
between packets and vary their packet size instead of their packet
rate in response to congestion. The congestion control mechanism in
this document cannot be used by those applications; TFRC-PS (for
TFRC-PacketSize) is a variant of TFRC for applications that have a
fixed sending rate but vary their packet size in response to
congestion. TFRC-PS will be specified in a later document.


which doesn't seem to describe the variant of TFRC described in the
tfrc-voip draft. Was your intent with this change to equate the two?

After a fashion. This is discussed in more detail in Section 6, on "TFRC-SP with Applications that Modify the Packet Size". Section 6 includes the following:

  "One possible use for TFRC-SP would be with applications that
  maintain a fixed sending rate in packets per second, but modify
  their packet size in response to congestion.  ...
  There are many questions about how an adaptive application would use
  TFRC-SP that are beyond the scope of this document."

What if I add a pointer in Section 2 to the fuller discussion
in Section 6?

That would help, but I'd prefer it if this draft didn't explicitly equate the small packet variant with TFRC-PS, since they're not really the same thing. A simpler fix would be to delete the text "RFC 3448 refers to this variant of TFRC as TFRC-PS, for applications that might vary their packet size in response to congestion" from Section 2.


Colin