I have revised draft-ietf-dccp-rfc3448bis, in response
to feedback to draft-ietf-dccp-rfc3448bis-01.txt (dated March 4),
and I also read over the entire draft and make a round of
The revised draft is at:
I have finished all of the changes that I want to make, and I think that
the draft is now in good shape, so the only further changes will be
from feedback from the WG or from the larger IETF. The changes
that I made include the addition of optional feedback from the
receiver called "Limited Receive Rate".
Feedback is of course appreciated.
Changes from draft-ietf-dccp-rfc3448bis-01.txt:
* Feedback from Arjuna Sathiaseelan:
- Changing W_init to be in terms of segment size s, not MSS.
* Changed THRESHOLD, the lower bound on the history
discounting parameter DF, from 0.5 to 0.25, for more
history discounting when the current interval is long.
* Clarified that the TFRC sender does not get to accumulate
`credits' of more than max(t_ipi,t_gran) time units in packet
scheduling, so the sender is not allowed to send arbitrary
bursts of packets after idle periods. From Gerrit Renker.
* More detailed specification of dealing with the first feedback
packet after an idle period.
- Added a variable "Limited Receive Rate" to the feedback packet
to indicate feedback packets after an idle period.
- Clarified that when the receiver receives a data packet,
and didn't send a feedback packet when the feedback timer
last expired (because no data packets were received),
then the receiver sends a feedback packet immediately.
- Clarified that the feedback packet reports the rate over
the last RTT, not necessarily the rate since the
last feedback packet was sent (if no feedback packet was
sent when the feedback timer last expired).
- Clarified that for a data-limited sender in slow-start, the
sender is limited to at most twice the receive rate, or
the initial window, whichever is larger, even after a
If (sender has been idle or data-limited
within last two round-trip times)
If (feedback packet reports Limited Receive Rate
or sender has been data-limited)
for the sender not being limited by reported receive rate
if twice the receive rate is less than W_init/R.
- Corrected earlier code designed to prevent the receive
rate from limiting the sending rate when the first feedback
packet received, or for the first feedback packet received
after an idle period. Added an explanation in the text.
* Clarified that we have p=0 only until the first loss event.
After the first loss event, p>0, and it is not possible to go
back to p=0. In response to old email.
* Clarified in Section 6.1 that the loss event rate does not
have to be recalculated with the arrival of each new data
* Clarified Section 4.6 on Reducing Oscillations. Feedback from