arnstein@panix.com (David Arnstein) hath wroth:
>I have a simple network using these Buffalo Tech boxes:
>WHR-HP-G54 router
>WLI-TX4-G54HP ethernet bridge
>
>I also have
>PC, with 100 Mbit/s. duplex NIC.
>Netgear EVA700 media extender, with unknown NIC.
>
>In case anyone cares, I have found that both Buffalo Tech boxes are
>solidly dependable and pleasant to use. The Netgear product is pretty
>rough.
>
>I am experimenting with streaming MPEG video from my PC, to the router,
>to the bridge, and finally to the EVA700. I am using the wired ethernet
>port of the EVA700 because its implementation of 802.11g is completely
>broken.
>
>Anyway, I am surprised that the highest rate MPEG bitstream I can play
>is about 9.5 Mbit/s. Any faster than that, and the Buffalo Tech boxes
>appear to be sending data 100% of the time, and the EVA700 can't play
>the bitstream fast enough.
What speed throughput do you require?
TCP or UDP? If streaming media, probably UDP.
What did you do to measure the thruput? I suggest using IPerf.
>When streaming at 9.5 Mbit/s. the Buffalo Tech boxes send data for (very
>roughly) 8 seconds, and then idle for about 2 seconds. I consider this
>to be the mark of success: the data buffers of the EVA700 are kept
>relatively full, with bandwidth to spare.
No. It's more likely that the wireless has choked on an error of some
sorts and is stalled waiting for interference to go away, or
re-establish a connection. Make life easy and use a benchmarking tool
to measure thruput and streaming performance and don't muddle the
testing with your MPEG application. The mystery MPEG appliacation
might have it's own buffering or FIFO problems.
>I do see a lot of other 802.11g networks present, but they seem to be
>spread out pretty well. I seem to recall one evening when I had channel
>2, and all the other networks were on channels 6 and 11. I still couldn't
>stream very fast.
The WHR-HP-G54 router (firmware v1.40) defaults to auto channel
select. I don't consider this a good idea. I suggest CH 1 for your
setup.
>The two Buffalo Tech boxes are separated by a wood and gypsum wall, and
>about 20 feet of air. I will experiment with moving the boxes closer
>together, but this will require buying more ethernet cables. I have
>already spent a lot of money on this little project. Before I dive into
>my wallet again, I'd like to know if this is typical performance.
>802.11g is described as a 54 Mbit/s. standard, so my 9.5 Mbit/s. "personal
>best" seems a bit weak. These Buffalo Tech boxes boast "high power,"
>"MIMO," and "turbo." All marketing speak, perhaps.
The MIMO is pure Buffalo marketing baloney. If you decode the
accompany promotional pollution, it says that the high power gives the
equivalent speed of a real MIMO router. There's no MIMO anywhere in
sight and all Buffalo is trying to do is mislead you into thinking
it's the latest greated acronym. Amazing how marketting can hype and
screwup an otherwise excellent product.
Your speed is dependent on your wireless connection speed. Login to
your WLI-TX4-G54HP wireless bridge status page and extract the speed
at which it's connecting to the WHR-HP-G54 router. Your UDP
throughput will be about half of the connection speed. So, if you're
connected at 36Mbits/sec, you should see about 18Mbits/sec thruput if
everything else is perfect.
The absolute maximum theoretical speeds for various technologies are
in the FAQ at:
http://wireless.wikia.com/wiki/Wi-Fi...ance_and_Speed
I'm not suprised that you're only getting 9.5Mbits/sec going through a
wall. It's not the wall that's probably slowing you down. It's the
reflections off the other parts of house. Try it closer and without
the wall involved to see what happens. If it's a signal strength
issue, installing higher gain antennas will help.
I have some suggestions for improving throughput. Turn OFF all the
enhancements and automatic balony in the router.
1. Disable 802.11b compatibility. It should be 802.11g only.
2. Disable auto channel selection and fix the channel number to
something usable (1, 6, or 11).
3. Disable auto speed control and fix the speed to something
reasonable. This will reduce the constant changes in speed as the
access point trys to maximize the connection speed.
4. Disable the 125MHz "burst mode" feature unless all your clients
have this feature and unless you are fairly close to the access point
(i.e. same room). One client without "burst mode" and things slow
down slightly.
--
Jeff Liebermann
jeffl@comix.santa-cruz.ca.us
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
Expected speeds for a Buffalo Tech 802.11g network 
Linear Mode
