I have submitted the revised version of draft-ietf-dccp-rfc3448bis-01, available from "http://www.icir.org/floyd/papers/draft-ietf-dccp-rfc3448bis-01.txt";, and the list of changes and some known open issues is appended below. If people could look at the changes and check them, that would be great. It would also be good to have feedback on the open issues: limitations by X_recv after a loss event; using DCCP's Receive Rate Length instead of ignoring one feedback packet?; mechanism for limiting the burst size? Is there consensus on any of these, that I have missed? Or other issues that I have missed? Many thanks, - Sally http://www.icir.org/floyd/ Changes from draft-ietf-dccp-rfc3448bis-00.txt: * When initializing the loss history after the first data packet sent is lost or ECN-marked, TFRC uses a minimum receive rate of 0.5 packets per second. * For initializing the estimated packet drop rate for the first loss interval when coming out of slow-start, it is ok to use the maximum receive rate so far, not just the receive rate in the last round-trip time. Feedback from Ladan Gharai. * General feedback from Gorry Fairhurst: - Added a reference for TFRC-SP. - Clarified that R_m is sender's estimate of RTT, as reported in Section 3.2.1. - Added a definition of terms. - Added a discussion of why the initial value of the nofeedback timer is two seconds, instead of three seconds for the recommended initial value for TCP's retransmit timer. * General feedback from Arjuna Sathiaseelan: - Added more details about sending multiple feedback packets per RTT. - Added change to Section 4.3 to use the first feedback packet, or the first feedback packet after a nofeedback timer during slow-start, *if min_rate > X*. * General feedback from Gerrit Renker: - Changed "delta" to "t_delta". - Changed X_calc to X_Bps, clarified X. - Clarified send times in Section 4.7. - Changed so that tld can be initialized to either 0 or -1. - Fixed Section 5.5 to say that the most recent lost interval has weight 1/(0.75*n) *when there have been at least eight loss intervals*. - Clarified introduction about fixed-size and variable-size packets. * Added more about sender-based variants. Feedback from Guillaume Jourjon. * Corrected that the loss interval I_0 includes all transmitted packets, including lost and marked packets (as defined in Section 5.3 in the general definition.) Email from Eddie Kohler and Gerrit Renker. * Open issue: Feedback from Ian about problems being limited by X_recv after a loss event. There might not be an easy answer. * Related open issue: Add Faster Restart to RFC3448bis? Or not? From Ian McDonald. * Open issue: Adopt something like DCCP's Receive Rate Length, instead of ignoring one feedback packet? From Eddie Kohler. * Open issue: Add possible mechanisms for limited the maximum burst size? Using a token bucket size based on the current rate? Or not? Email from Eddie Kohler and Gerrit Renker. * Related open issue: To deal with idle periods and the like, in Section 4.7 say that t_i := max(t_i, t_now - RTT/2), to limit bursts to RTT/2 packets? Has anyone implemented this? Email from Eddie Kohler and Ian McDonald. * Not done: I didn't add a minimum value for the nofeedback timer. (Why would a nofeedback timer need to be bigger than max(4*R, 2*s/X)? Email discussing pros and cons from Arjuna. * Not addressed yet: Email thread on "RFC 3448, 4.4: Modifying X_recv if p = 0 at the time of last feedback". * Todo: Update Section 9 on "Changes from RFC 3448" with changes since draft-floyd-rfc3448bis-00.txt.
