Homeplug compability problem - SMC 14 Mbps vs Edimax 85 Mbps

Hi!
I have been using four SMC homeplug 14 Mbps units at home, and this
has been working great. The only problem is that 14 Mbps is not good
enough for streaming video etc from one pc to another.
Therefore, I just bought two new units, but this time it was Edimax 85
Mbps. The boxed look almost identical, so I guessed it was the same
content but upgraded to 85 Mbps and with different branding.

When replacing one of the old SMC boxes with the new Edimax unit, the
Edimax apparently could not communicate with the remaining SMC units.
In fact, it seemed as if I the SMC units stopped working after I plug
in the Edimax unit..
Anyone have any experience or knowledge about this? Is there some
reason why these two cant be used along each other?

Regards, Per Magnus

 

Does the Edimax unit support *HomePlug* standards? The SMC units will
only work at that speed.

 

I have a few of those 14Mbit/sec SMC EZ-Connect Ethernet boxes I
picked up cheap. Everything slows down when I turn on the shop
flourescent lights and stops when I run the vacuum cleaner.
Interestingly, there's no effect from other motors in the house. We
have 6 houses on our AC power transformer and the boxes work between
any of these house.

Have you actually measured your delivered thruput? Try IPerf:
<http://dast.nlanr.net/Projects/Iperf/>
Setup two machines. One one, run the server part as:
iperf -s
On the other, run the client as:
iperf -c ip_address_of_server_machine
I get about 5 Mbits/sec on the SMC's when things are working and about
half that when the noisy lights are running.

You should see about 20-25Mbits/sec with your 85Mbit/sec units.

Nope. Different chipsets. I forgot if they use Intellon, Connexant,
Arkados, or Maxim chips. Probably Intellon.

Both technologies use the same 2-28MHz frequency range on the power
line but with radically different modulation characteristics. More
simply, they interfere with each other. There is no downward
compatibility from the new AV 200Mbit/sec to 85Mbits to 14Mbits/sec.
It is compatible with BPL (broadband powerline) systems.

This may help explain things:
<http://www.powerlinenetworking.co.uk/content/view/39/51/>

Note that neither Edimax or SMC are listed as HomePlug compliant:
<http://www.homeplug.org/en/products/products.asp>
However, they may have private labelled a complaint product. Dunno
for sure.

I couldn't find an 85Mbit/sec product on the Edimax web site. Is
there some reason that you didn't bother to disclose any model
numbers?
<http://www.edimax.com>

Some light reading:
<http://www.extremetech.com/article2/0,1697,1151592,00.asp>

Incidentally, this is a wireless networking newsgroup. You might try
searching for a more appropriate group, blog, or mailing list.

 

Thank you for great response, Jeff!
That explains why I was experiencing the problems...

The diagnostics util which follows SMC seems to display speeds up to
11 Mbit/s, but haven't really tried Iperf. I have only experienced
that music streams ok, and that video files (divx) seem to be lagging
sometimes. Therefore the upgrade to 85Mbit..

The Edimax unit I am using is:
Edimax, HP-8500 HomePlug Ethernet Bridge 85MB

I guess I'll just have to upgrade the whole lot of units, then, since
they dont work alongside.

Thanks!

-Per Magnus

 

You may actually be able to use them both at the same time, just not see
each other.. I have both a few (netgear) 14 Mbps units AND a Netgear 85 Mbps
on the system at the same time... One (the slower) for sharing small files
and music, and the other higher speed one for video files (My toshiba/Tivo
records and stores programs on my network storage.). Point is it is
possible, just don't know if it is possible with those specific devices
I have one unit of each speed plugged into my wap/router and the ac, and can
go anywhere in the house and get whatever speed the unit does when I plug it
in... FWIW Netgear also makes a 200 Mbps device (however for Gigabit
ethernet devices), but the fact that powerline can do 200 Mbps with those,
says to me you sure should be able to do powerline with combinations of
slower stuff that add up to less than 200...

 

Have you tried RFI filters?

<http://www.homeplug.org/en/faq/>:

HomePlug AV co-exists with HomePlug 1.0.

Also, 100 Mbps is a more meaningful characterization of HomePlug AV:

HomePlug AV has pushed Shannon's Law to its limit and provides a
200Mbps class service at the PHY layer. After overhead
considerations, the MAC layer will support over 100Mbps.

 

No. That would be too easy. It's more fun to complain.

My whole house is one big source of RFI and EMI. Ham radio, test
equipment, assorted motors, computahs, etc. Some big ferrite beads
would probably solve the flouresent light problem. I have a nicely
filtered portable power test box. I'll try it on the vacuum cleaner
when I get inspired to clean house.

Maybe something like these if I can't find any big ferrite beads in my
junk box:
<http://www.smarthome.com/4845acf.html>
<http://www.smarthome.com/4845.html>
<http://www.smarthome.com/1626-10.html>