WDS - three nodes

Hi,

I have two WRT54Gs running Firmware: DD-WRT v23 (12/25/05) in WDS mode.

If I add a third WRT54G in WDS will it make a difference to the performance
of the network ** depending on which of the existing APs it connects to **.
(I know throughput will halve again.)

I have a desktop with a PCI WiFi adaptor upstairs, but its connection is
wholly reliable, which is annoying as I have a PS2 which shares its internet
connection.

I was thinking that if I add a WRT54G upstairs and have the desktop and PS2
connect into this via CAT5, this AP might give a more reliable connection
with the other APs in the house (particularly since with DD-WRT you can
boost the xmitter power.

Thanks.

Sorry - that's wholly unreliable.

And what I'm asking is will the connection be faster if the 3rd (new) AP
connects to the first (gateway) AP, rather than the second AP. Does the
number of APs in the chain slow down data transfer significantly?

"__spc__" <the.constantines@btinternet.com> wrote in message
news:dIGdnQkMPedrwp_YnZ2dnUVZ8tadnZ2d@bt.com...
> Hi,
>
> I have two WRT54Gs running Firmware: DD-WRT v23 (12/25/05) in WDS mode.
>
> If I add a third WRT54G in WDS will it make a difference to the
> performance of the network ** depending on which of the existing APs it
> connects to **. (I know throughput will halve again.)
>
> I have a desktop with a PCI WiFi adaptor upstairs, but its connection is
> wholly reliable, which is annoying as I have a PS2 which shares its
> internet connection.
>
> I was thinking that if I add a WRT54G upstairs and have the desktop and
> PS2 connect into this via CAT5, this AP might give a more reliable
> connection with the other APs in the house (particularly since with DD-WRT
> you can boost the xmitter power.
>
> Thanks.
>

On Sat, 9 Sep 2006, __spc__ wrote:

>
>
> Sorry - that's wholly unreliable.
>
> And what I'm asking is will the connection be faster if the 3rd (new) AP
> connects to the first (gateway) AP, rather than the second AP. Does the
> number of APs in the chain slow down data transfer significantly?
>

The Cisco commerical access point recommended configuring an ap with the
radios off at large user count sites to act as WDS primary so that it can
do its primary stuff without CPU capacity issues on the AP slowing down
users.

The WRT54 consumer units probably have less CPU capacity to spare but also
you'll have a lot fewer users than a large site.

Measure it and tell us how it works. Watch the load average in the
dd-wrt software.

"__spc__" <the.constantines@btinternet.com> hath wroth:

>I have two WRT54Gs running Firmware: DD-WRT v23 (12/25/05) in WDS mode.
>
>If I add a third WRT54G in WDS will it make a difference to the performance
>of the network ** depending on which of the existing APs it connects to **.
>(I know throughput will halve again.)

Yes. Maximum thruput will drop. However, you may not see the effect
if your internet connection is relatively slow. For example, let's
say you have a typical 1.5Mbit/sec DSL line. The first wireless hop
gets a 36Mbit/sec connection for a maximum thruput of 18Mbits/sec. The
2nd hop gets the same 36Mbits/sec connection speed, with the same
18Mbits/sec thruput from the 2nd radio. However, because only one
xmitter can be on the air at a time, the system thruput goes down to
9Mbit/sec. However, you'll never see the loss in thruput because your
download speed is limited by the 1.5Mbit/sec DSL connection.

More reading on the topic. Note that there is some controversy as to
whether the maximum thruput drops linearly or exponentially:
| http://dailywireless.org/modules.php...rder=0&thold=0
| http://wifinetnews.com/archives/003972.html
| http://www.smallworks.com/archives/00000072.htm
Note that WDS is really a form of mesh networking.

>I have a desktop with a PCI WiFi adaptor upstairs, but its connection is
>wholly reliable, which is annoying as I have a PS2 which shares its internet
>connection.

Run some CAT5 wire.

>I was thinking that if I add a WRT54G upstairs and have the desktop and PS2
>connect into this via CAT5, this AP might give a more reliable connection
>with the other APs in the house (particularly since with DD-WRT you can
>boost the xmitter power.

You would do better to have a simple access point downstairs (for your
PS2 and desktop), with a CAT5 wire to either the main router, or if
that's not possible, to the 2nd router that's running WDS. Neither
arrangement has any speed loss involved. That also allows you to use
a different RF channel for this access point, so that there's no
mutual interference.


--
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

"__spc__" <the.constantines@btinternet.com> wrote in message
news:dIGdnQkMPedrwp_YnZ2dnUVZ8tadnZ2d@bt.com...
> Hi,
>
> I have two WRT54Gs running Firmware: DD-WRT v23 (12/25/05) in WDS mode.
>
> If I add a third WRT54G in WDS will it make a difference to the
> performance of the network ** depending on which of the existing APs it
> connects to **. (I know throughput will halve again.)
>
> I have a desktop with a PCI WiFi adaptor upstairs, but its connection is
> wholly reliable, which is annoying as I have a PS2 which shares its
> internet connection.
>
> I was thinking that if I add a WRT54G upstairs and have the desktop and
> PS2 connect into this via CAT5, this AP might give a more reliable
> connection with the other APs in the house (particularly since with DD-WRT
> you can boost the xmitter power.
>
> Thanks.

Hi,

I'm just paralleling what Jeff already said, albeit less technically, but I
used to play around with WDS quite a bit.

Not only does it halve things, but it also causes some real nastyness as
well. After looking closely at what was going on with SNMP software, I
stopped doing the whole repeating thing all together. While it works "well
enough" for internet traffic, its really not an efficient way to extend a
WLAN out for point-to-point traffic.

As Jeff said, try to run them as completetly "seperate access points", on
seperate channels. You may have to play a bit to find the most efficient
seperation.

You don't have to run CAT5 for a seperate AP if you as a wireless-ethernet
bridge. I have one of my AP's connected through a bridge. Its using the
same SSID as the AP it is connected to, of which most of my client software
(laptop, PDA) are smart enough to switch between automatically as one or the
other's strength increases. Essentially, it is a "repeater" but without
cutting pipe in half. Works fine.

(I'm using mainly DLink stuff.)

__spc__ wrote:
> Hi,
>
> I have two WRT54Gs running Firmware: DD-WRT v23 (12/25/05) in WDS
> mode.
> If I add a third WRT54G in WDS will it make a difference to the
> performance of the network ** depending on which of the existing APs
> it connects to **. (I know throughput will halve again.)
>
> I have a desktop with a PCI WiFi adaptor upstairs, but its connection
> is wholly reliable, which is annoying as I have a PS2 which shares
> its internet connection.
>
> I was thinking that if I add a WRT54G upstairs and have the desktop
> and PS2 connect into this via CAT5, this AP might give a more
> reliable connection with the other APs in the house (particularly
> since with DD-WRT you can boost the xmitter power.
>
> Thanks.

You may want to consider a minor change... I have three Linksys WRT54G 's
(plural, not the GS) on my 10 acre place, two (in the house) connected by a
straight cat 5 (out of one to wan input of the next), and the third in the
outbuilding (800ft away but the same power as the house - buried underground
power cable), I used the netgear powerline networking (three types, one up
to 54Mb, two 85Mb/second, up too 200Mb, way faster than the input
connection) and use the output from the powerline network as the wan input
the the third.. Same ssid on all 3, have one huge hotspot....

Netgear product webpage
http://www.netgear.com/Products/Brid...Extenders.aspx
(only shows the 54 and 84Mb models)

Have no idea if that same scenario would work with WDS..... Can't see why
not, and you wouldn't suffer from the halving speed problem...