<p dir="ltr">Also allow for "partially reliable" delivery as in SCTP. </p>
<div class="gmail_quote">On Dec 26, 2012 6:03 PM, "Detlef Bosau" <<a href="mailto:detlef.bosau@web.de">detlef.bosau@web.de</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Am <a href="tel:25.12.2012%2004" value="+12512201204" target="_blank">25.12.2012 04</a>:19, schrieb <a href="mailto:dpreed@reed.com" target="_blank">dpreed@reed.com</a>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<br>
Indeed, bandwidth is now meaningless as a term, just as "broadband" is. Once upon a time, both referred to bounds on the frequency components of the physical layer signal, both in wires (twisted pair, coax, etc) and in RF. The RF bandwidth of 802.11b DSSS modulation was about 10 MHz, whereas the bitrate achieved was about 2 Mb/sec. Now we use OFDM modulation in 802.11n, with bandwidths of 40 MHz more or less, but bitrates of >> 40 Mb/sec. (yes, that is mostly because of 64-QAM, which encodes 6 bits on each subcarrier within an OFDM "symbol").<br>
<br>
What causes the 802.11n MAC protocol to achieve whatever bitrate it achieves is incredibly complex. Interestingly, in many cases the problem is really bad due to "bufferbloat" in the 802.11n device designs and drivers, which causes extreme buildup of latency, which then causes the TCP control loops to be very slow in adapting to new flows sharing the path.<br>
<br>
<br>
</blockquote>
<br>
And this refers directly to my original question.<br>
<br>
May I put it in very simple words.<br>
<br>
In mobile networks (let's include wifi there) a packet is either reliably delivered - in unpredictable time.<br>
Or it is unreliably delivered - that is possible in predictable time.<br>
<br>
Can we agree upon that?<br>
<br>
I still want to write my research proposal. However, I'm tired to get it rejected after exactly these two lines.<br>
<br>
Detlef<br>
<br>
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The nonsense that passes for knowledge around wireless networking,<br>
even taught by "professors of networking" is appalling. It's the<br>
blind leading the blind. (D.P. Reed, 2012/12/25)<br>
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