Access point /bridge recommendations (g-mode) ?

I've been using a DLink DWL-900AP for over a year to link two WIRED
networks, about 5 PC's on each site. It's been working pretty well,
but not the fastest, but never a dropout or reconnect needed. Line of
sight between the two, about 100 feet outdoors, with original omni
antennas.

Can anyone suggest a reasonable cost bridge model (g) to try? I tried
the DLink DWL-2100AP; basically assigned the mac single point to point
bridge for security. Although faster, we experienced so many
"pauses", and a few out and out "the network has been disconnected"
messages, that I went back to our original b-model DLink.

I tried different channels, disabled super-g mode, etc. all without
any better luck.

Any experience here with other bridges? I am going to put in a
directional antennas so I need a bridge/access point that supports
that.

I was disappointed with the DLink, but it may have been partially my
fault for not replacing the antennas with directional ones to minimize
interference.

I guess DLink, Netgear, Linksys are possible choices, plus Cisco
Aironet being a more expensive solution.

All ideas and experience appreciated.

john

On Tue, 28 Sep 2004 15:53:08 -0700, John . <(E-Mail Removed)> wrote:

>I've been using a DLink DWL-900AP for over a year to link two WIRED
>networks, about 5 PC's on each site. It's been working pretty well,
>but not the fastest, but never a dropout or reconnect needed. Line of
>sight between the two, about 100 feet outdoors, with original omni
>antennas.

What do you mean "not the fastest"? I have 4ea different customers
linked with DWL-900AP+ bridges. Thruput is about 15Mbits/sec. Are
you using a DWL-900AP (no plus) or the plus version? They're quite
different. The plus version uses the TI chipset that does
22Mbits/sec. The version 2 mutation of the DWL-900AP+ will do 802.11g
with a fireware update. The one pair I have that's running 802.11g is
getting about 20Mbits/sec at 100ft.

However, none of the 4ea bridged pairs use the insipid stock antenna.
My guess is that you don't have enough signal to get the full 22 (or
more) Mbits/sec data rate. The radios detect errors, and slow down
the data rate until the error rate improves. You may not be seeing
any errors, but you also may not be getting the highest possible data
rate. Replaceing the radios with another model will only cause the
same problems if you use the stock antennas.

You can get a cheap performance boost with reflectors. See:
http://www.freeantennas.com/projects/Ez-10/
I'm not a huge fan of such antennas, but they do work.

What I did on all 4ea pairs of bridges was attach a pigtail and a 9dBi
Maxrad panel antenna.
http://www.fab-corp.com/J1.htm ($25 half way down page)
One pair has my home made panel antennas of dubious design and
construction. Even so, it works MUCH better than the stock antennas.

What thruput speed were you expecting?

>Can anyone suggest a reasonable cost bridge model (g) to try? I tried
>the DLink DWL-2100AP; basically assigned the mac single point to point
>bridge for security. Although faster, we experienced so many
>"pauses", and a few out and out "the network has been disconnected"
>messages, that I went back to our original b-model DLink.

There have been several reports of unreliable and erratic operation
with the DWL-2100AP in this newsgroup. Use Google groups to search
for the messages.

>I tried different channels, disabled super-g mode, etc. all without
>any better luck.
>
>Any experience here with other bridges? I am going to put in a
>directional antennas so I need a bridge/access point that supports
>that.

Yes. I have some experience with 802.11b bridges. However, no
experience with 802.11g bridges. They do exist, but are pricy:
http://www.streakwave.com/Product-Bridge-80211g.asp

>I was disappointed with the DLink, but it may have been partially my
>fault for not replacing the antennas with directional ones to minimize
>interference.
>
>I guess DLink, Netgear, Linksys are possible choices, plus Cisco
>Aironet being a more expensive solution.
>
>All ideas and experience appreciated.
>
>john



--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558

Jeff Liebermann <(E-Mail Removed)> wrote:

>On Tue, 28 Sep 2004 15:53:08 -0700, John . <(E-Mail Removed)> wrote:
>
>>I've been using a DLink DWL-900AP for over a year to link two WIRED
>>networks, about 5 PC's on each site. It's been working pretty well,
>>but not the fastest, but never a dropout or reconnect needed. Line of
>>sight between the two, about 100 feet outdoors, with original omni
>>antennas.
>
>What do you mean "not the fastest"? I have 4ea different customers
>linked with DWL-900AP+ bridges. Thruput is about 15Mbits/sec. Are
>you using a DWL-900AP (no plus) or the plus version? They're quite
>different. The plus version uses the TI chipset that does
>22Mbits/sec. The version 2 mutation of the DWL-900AP+ will do 802.11g
>with a fireware update. The one pair I have that's running 802.11g is
>getting about 20Mbits/sec at 100ft.

I have two of the DWL-900AP+. I measured actual PC to PC throughput
over the wireless bridge at 3 to 4 Mbps using Qcheck (www.netiq.com).
Supposedly 3-4 Mbps is good ACTUAL data transfer throughput for
802.11b. Qcheck is a very nice (free) network tester.

Of course, when opening a large file (>10 megabytes) across the
wireless, it was "not the fastest". Internet access across the bridge
was fine of course.

>
>However, none of the 4ea bridged pairs use the insipid stock antenna.
>My guess is that you don't have enough signal to get the full 22 (or
>more) Mbits/sec data rate. The radios detect errors, and slow down
>the data rate until the error rate improves. You may not be seeing
>any errors, but you also may not be getting the highest possible data
>rate. Replaceing the radios with another model will only cause the
>same problems if you use the stock antennas.

I agree and am in process of replacing the stick antennas now with two
30 degree beam width patch antennas. I think that will take care of
the signal drop, slowdowns, and possible interference in the
neighborhood (I found several wifi signals easily with my Pocket PC).

http://www.sharperconcepts.net/produ...products_id=49


>
>You can get a cheap performance boost with reflectors. See:
> http://www.freeantennas.com/projects/Ez-10/
>I'm not a huge fan of such antennas, but they do work.
>
>What I did on all 4ea pairs of bridges was attach a pigtail and a 9dBi
>Maxrad panel antenna.
> http://www.fab-corp.com/J1.htm ($25 half way down page)
>One pair has my home made panel antennas of dubious design and
>construction. Even so, it works MUCH better than the stock antennas.
>
>What thruput speed were you expecting?
>
>>Can anyone suggest a reasonable cost bridge model (g) to try? I tried
>>the DLink DWL-2100AP; basically assigned the mac single point to point
>>bridge for security. Although faster, we experienced so many
>>"pauses", and a few out and out "the network has been disconnected"
>>messages, that I went back to our original b-model DLink.
>
>There have been several reports of unreliable and erratic operation
>with the DWL-2100AP in this newsgroup. Use Google groups to search
>for the messages.

Thanks, and yes, I saw those too after buying (and testing and
returning) the 2100AP's.

>
>>I tried different channels, disabled super-g mode, etc. all without
>>any better luck.
>>
>>Any experience here with other bridges? I am going to put in a
>>directional antennas so I need a bridge/access point that supports
>>that.
>
>Yes. I have some experience with 802.11b bridges. However, no
>experience with 802.11g bridges. They do exist, but are pricy:
> http://www.streakwave.com/Product-Bridge-80211g.asp
>
>>I was disappointed with the DLink, but it may have been partially my
>>fault for not replacing the antennas with directional ones to minimize
>>interference.
>>
>>I guess DLink, Netgear, Linksys are possible choices, plus Cisco
>>Aironet being a more expensive solution.
>>
>>All ideas and experience appreciated.
>>
>>john
>
>

Thanks. I still haven't figured out what 802.11g bridges to buy.
Currently researching Linksys WET54G and Netgear WGE101--both have
RP-SMA connectors.

Anyone with experience with these (or other bridges), please comment.

john

On Wed, 29 Sep 2004 00:51:33 -0700, John . <(E-Mail Removed)> wrote:

>I have two of the DWL-900AP+. I measured actual PC to PC throughput
>over the wireless bridge at 3 to 4 Mbps using Qcheck (www.netiq.com).
>Supposedly 3-4 Mbps is good ACTUAL data transfer throughput for
>802.11b. Qcheck is a very nice (free) network tester.

Something is wrong(tm). With a 22mbit/sec association, I'm getting
10-12Mbits/sec thruput using the same program and some SNMP based
monitoring tools. I have it set to point-to-point bridge, single
antenna, 4x mode enabled, and short preamble. You can't easily tell
if you're using 22mbits/sec data rate as Dlink doesn't supply much in
the way of diagnostics. However, the thruput should be sufficient as
6mbits/sec thruput is what you'll get with 11Mbit/sec 802.11b
association, and anything faster must be at 22mbits/sec.

>Of course, when opening a large file (>10 megabytes) across the
>wireless, it was "not the fastest". Internet access across the bridge
>was fine of course.

A 10MByte file will take 20 seconds to open at your 4Mbits/sec and 6.7
seconds at my 12Mbits/sec thruput. Two of my links run remote cash
registers, which operate on an ancient and LAN hostile database
application which opens big files. 10MBytes is about the typical
database size and the stupid application wants to shovel all of it
across the wireless LAN to extract one lousy transaction. I'm getting
about 2 seconds to retreive a record, which is adequate.

Like I said: What manner of performance were you expecting?

>I agree and am in process of replacing the stick antennas now with two
>30 degree beam width patch antennas. I think that will take care of
>the signal drop, slowdowns, and possible interference in the
>neighborhood (I found several wifi signals easily with my Pocket PC).
>
>http://www.sharperconcepts.net/produ...products_id=49

I'm getting timeouts from their web pile. Yep, antennas are the right
approach. Keep the coax cables to a minimum. One important trick
with the DWL-900AP+ is to remove the gold lock washer from the R-SMA
connector on the box. The R-SMA connector on the pigtail will not
bottom out properly with the lockwasher in place.

Try the WET54GS5. I haven't tried it yet, but it looks good on paper.
http://www.tomsnetworking.com/Review...D-WET54GS5.php
The GS does NOT mean that it does Turbo-G (channel bonding). It's
pure 802.11g. What looks nice for me is that it does QoS in the box,
which means I can prioritize my VoIP, streaming background music, and
cash register traffic. The VLAN feature also looks nice to keep the
junk traffic to a minimum.

Aggregate thruput appears not much better than the DWL-900AP+. See:

http://www.tomsnetworking.com/Review...throughput.png
Mbits/sec Conditions
24 6ft same room
14 30ft sheet rock wall
3 40ft 1 wood floor
2 50ft 3 walls
At 100ft, methinks you'll be in the 10-14Mbit/sec range. Play with
the antennas. Methinks that's your key to better performance.



--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558

Jeff Liebermann <(E-Mail Removed)> wrote:
>I'm getting timeouts from their web pile. Yep, antennas are the right
>approach. Keep the coax cables to a minimum. One important trick
>with the DWL-900AP+ is to remove the gold lock washer from the R-SMA
>connector on the box. The R-SMA connector on the pigtail will not
>bottom out properly with the lockwasher in place.
>
Thanks for the input and tip on RP-SMA connector. The patch panel has
5' cable.

I'll retest before and after throughput with new antennas and post
results. I agree and bet I'll get better performance with the
DWL-900AP+ with just a better signal.

Ham radio 101!

john