On 11/25/06, Gerrit Renker <gerrit@xxxxxxxxxxxxxx> wrote:
[CCID 3]: Consolidate timer resets The specification in [RFC 3448, 4.4, step (3)] is impossible to implement: when no feedback has been received, the value of RTT is undefined as per [RFC 3448, 4.2]. Hence we can not set the timeout value to max(4*R, 2*s/X) as step (3) suggests. The most reasonable solution is to remain at the initial timeout value of 2 seconds, as per [RFC 3448, 4.2] - until an estimate for R has been computed.
But RFC4342 says: If the sender hasn't received a feedback packet from the receiver when the nofeedback timer expires, then the sender halves its allowed sending rate. The allowed sending rate is never reduced below one packet per 64 seconds. Note that not all acknowledgements are considered feedback packets, since feedback packets must contain valid Loss Intervals, Elapsed Time, and Receive Rate options. If the sender never receives a feedback packet from the receiver, and as a consequence never gets to set the allowed sending rate to one packet per RTT, then the sending rate is left at its initial rate of one packet per second, with the nofeedback timer expiring after two seconds. The allowed sending rate is halved each time the nofeedback timer expires. Thus, if no feedback is received from the receiver, the allowed sending rate is never above one packet per second and is quickly reduced below one packet per second. -- Ian McDonald Web: http://wand.net.nz/~iam4 Blog: http://imcdnzl.blogspot.com WAND Network Research Group Department of Computer Science University of Waikato New Zealand - To unsubscribe from this list: send the line "unsubscribe dccp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
