pfarrell Wrote: > rudholm wrote: > > ceejay Wrote: > > > >>Well, at the top end: a 100Mbps LAN should give you about 50Mbps of > >>usable throughput, so divide 50,000 by 256 to get 195 theoretical > >>streams. > > > > 50Mbps? > > > > I'm curious why you don't expect 100Mb/second from your 100Mb/second > > Ethernet. > > Because Ethernet uses Carrier Sense Multiple Access with Collision > Avoidance to control traffic. No Ethernet can deliver its rated > speed, even getting 50% of its rated speed is hard if not impossible > if > there is any sharing of the network. > > And then you have to add overhead, addressing, error correcting, > ack/nak > messages, etc. > > For a practical example for Slim users, a WiFi 'b' network is > rated as 11 megabits/second but it rarely can actually > delivery uncompressed audio. This is a problem for SB1 users, > since the SB1 only does WiFi B, and can't do Flac on the fly > > The RedBook specifies that stereo music is to be recorded in 16-bit > PCM > sampled at 44.1 kHz. A little arithmetic shows that the data stream of > CD audio must be at least: > > Data Rate = "X" > = 16 bits * 2 channels * 44.1kHz > = 16 * 2 * 44100 > = 1,411,200 bits/second > = 176,400 bytes/second > = 172 Kbytes/second > > So while Red Book (or uncompressed audio) is only 1.4 mb/s and that > is only 12% or so of a WiFi "b" link speed, you can't get it. > > Assuming that you can get 10% of the rated speed is probably good > engineering. > > > -- > Pat > http://www.pfarrell.com/music/slimserver/slimsoftware.html
Whist I agree that you don't get 100%, I think your numbers are somewhat on the pessamistic side. I get over 80% of theoretical on my gigabit lan without any tweaking, without jumbo frames, and with the cheapest lan cards I could buy ($10 each). Not bad. As for your 802.11b - again the myth that you can't run pcm to an sb1 is just that - a myth. I was doing it for a long time before I finally replaced my sb1 with a later model. Sure there was the odd glitch because that buffer was so small but in general it worked fine. This was with a normal consumer access point through several walls and with less than 80% signal strength in a noisy (rf wise) apartment building. -- radish ------------------------------------------------------------------------ radish's Profile: http://forums.slimdevices.com/member.php?userid=77 View this thread: http://forums.slimdevices.com/showthread.php?t=24454 _______________________________________________ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/discuss
