2011/8/18 Gunnar Hellström <[email protected]>: > To me it seems that section 10.2 is sufficient, and your discussion is just > intended to clarify that, and give the mail list an example of one possible > algorithm. > > Though, if I understand the algorithm right ,GPRS with 3 second round-trip > would cause a transmission interval of 3 seconds or so. (?) I do not think > that it is needed to increase the transmission interval beyond one second > just because there is a long latency in the network.
In most cases, you are right. However, it's also important to determine what the latency spike is being caused by. GPRS is more usually closer to 500ms-1000ms latency. Whenever there's a latency spike, it's sometimes due to congestion, and if it is due to a bandwidth starvation scenario, then lengthening the interval is the best way to ensure the survival of XEP-0301 (where the alternative is potentially a spontaneous disconnection or several seconds of lagging of buffered-up 1000ms packets). Other times, latency spike are NOT caused by bandwidth starvation issues or overload issues, but you do not always know that. In situations of connections normally averaging 1000ms or less, spiking to 3000ms, it is usually the safest and lesser evil (less screen-to-screen latency) to lengthen the transmission interval, in order to reduce screen-to-screen lag by reducing the number of bytes that "piles up" in massive congestion. Also, I point out that your paragraph "section 10.2 is sufficient" appears to contradict the next paragraph, "I do not think that is needed..." because section 10.2 implies that it is needed. Sincerely, Mark Rejhon
