Does DLink DWL-G810 bridge networks?

From the DLink documentation I can't determine if the DWL-G810 bridge
can be used to interconnect 2 wired Lans into one?

I know the DWL-2100AP+ can do this.

But the DWL-G810 looks like it is used to support just ONE device.
Does anyone know if it will pass ALL ip's across the bridge from/to
the two lans?

I have 4 of the 2100 setup as a bridge and they kick but. The 4 houses are
about 3 - 4 miles from the main 2100 AP. All are connected to antennas on
there roofs.

Were going to be adding some more houses soon with more 2100's.

Thanks
Digital D


"John ." <(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> From the DLink documentation I can't determine if the DWL-G810 bridge
> can be used to interconnect 2 wired Lans into one?
>
> I know the DWL-2100AP+ can do this.
>
> But the DWL-G810 looks like it is used to support just ONE device.
> Does anyone know if it will pass ALL ip's across the bridge from/to
> the two lans?
>

On Thu, 07 Oct 2004 13:42:22 -0700, John . <(E-Mail Removed)> wrote:

>From the DLink documentation I can't determine if the DWL-G810 bridge
>can be used to interconnect 2 wired Lans into one?

No. One device, one MAC address, and one badly written data sheet.

>I know the DWL-2100AP+ can do this.
>
>But the DWL-G810 looks like it is used to support just ONE device.
>Does anyone know if it will pass ALL ip's across the bridge from/to
>the two lans?

Bridges don't know what to do with IP addresses, which run on Layer 3.
Bridges work on Layer 2, which are MAC addresses. The DWL-G810+
apparently (i.e. not absolutely sure) looks like a simple client-end
wireless bridge which will pass exactly one MAC address. This is in
contrast to the WET11, DWL-900AP+, DWL-2100AP+, and WAP11, which will
pass about 32 MAC addresses.

This is about the WET11 but might help explain the problem:
http://www.wi-fiplanet.com/reviews/article.php/1556351

Different types of wireless bridges:
http://www.wi-fiplanet.com/tutorials...le.php/1563991
I don't agree with their definitions and names, but I think you can
see the problem. There are a sufficiently wide variety of types (and
names) of wireless bridges to confuse anyone. If I get ambitious and
find some time, I'll scribble a web page with my names for the various
types of wireless bridges, which should add to the confusion.



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

What antennas are you using on the rooftop 2100s that connect 3-4 miles
apart?

LOS?

--
Bob Alston

bobalston9 AT aol DOT com
<(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>I have 4 of the 2100 setup as a bridge and they kick but. The 4 houses are
>about 3 - 4 miles from the main 2100 AP. All are connected to antennas on
>there roofs.
>
> Were going to be adding some more houses soon with more 2100's.
>
> Thanks
> Digital D
>
>
> "John ." <(E-Mail Removed)> wrote in message
> news(E-Mail Removed)...
>> From the DLink documentation I can't determine if the DWL-G810 bridge
>> can be used to interconnect 2 wired Lans into one?
>>
>> I know the DWL-2100AP+ can do this.
>>
>> But the DWL-G810 looks like it is used to support just ONE device.
>> Does anyone know if it will pass ALL ip's across the bridge from/to
>> the two lans?
>>
>
>


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

>On Thu, 07 Oct 2004 13:42:22 -0700, John . <(E-Mail Removed)> wrote:
>
>>From the DLink documentation I can't determine if the DWL-G810 bridge
>>can be used to interconnect 2 wired Lans into one?
>
>No. One device, one MAC address, and one badly written data sheet.
>

Maybe I misstated my question, but wouldn't ONLY ONE mac address be
passed between two DWL-G810's, the mac of the bridge? Even though
each wired LAN in two separate buildings has 5 or 6 PC's, wouldn't two
DWL-G810's just be passing traffic to/through the other corresponding
bridge?

DWLG810--pc1--pc2--pc3==>switch (all cat5e)
+
+
antennas
+
+
DWLG810--pc4--pc5--pc6==>switch (all cat5e)

Does this work?

On Fri, 08 Oct 2004 10:53:26 -0700, John . <(E-Mail Removed)> wrote:

>Jeff Liebermann <(E-Mail Removed)> wrote:
>
>>On Thu, 07 Oct 2004 13:42:22 -0700, John . <(E-Mail Removed)> wrote:
>>
>>>From the DLink documentation I can't determine if the DWL-G810 bridge
>>>can be used to interconnect 2 wired Lans into one?
>>
>>No. One device, one MAC address, and one badly written data sheet.

>Maybe I misstated my question, but wouldn't ONLY ONE mac address be
>passed between two DWL-G810's, the mac of the bridge? Even though
>each wired LAN in two separate buildings has 5 or 6 PC's, wouldn't two
>DWL-G810's just be passing traffic to/through the other corresponding
>bridge?
>
>DWLG810--pc1--pc2--pc3==>switch (all cat5e)
>+
>+
>antennas
>+
>+
>DWLG810--pc4--pc5--pc6==>switch (all cat5e)
>
>Does this work?

Nope. The problem is the type of bridge. Again, I'm guessing that
the DWL-G810+ is a "imple bridge and not a transparent bridge. It's
difficult to tell from the data sheet. The difference is that a
simple bridge only deals with one MAC address, while the transparent
bridge or "network bridge" is designed to connect two networks
together as in your ascii drawing.

Reminder: bridges deal with MAC addresses, not IP addresses. Let's
start with a wired LAN bridge. (Incidentally, a switch is a bridge
with more than 2 ports.) The wired bridge builds a table of MAC
addresses that it hears on each port. It looks something like:
Address Port
MAC1 1
MAC2 2
MAC3 1
MAC4 2
(...)
MAC30 2
MAC31 1
For convenience I decided the odd MAC addresses would be plugged into
port 1, while the even MAC addresses in port 2. The 802.3 ethernet
MAC address header includes the source and destination MAC address of
each packet. The source address is used to populate the table, while
the destination address is used to determine which port it needs to
traverse.

bridging decision time:
1. If the destination MAC address is in the bridge table, the packet
crosses the bridge.
2. If the destination MAC address is in the bridge table, but on the
same port as the originating MAC address, the packet does NOT cross
thr bridge (because it has nowhere to go).
3. If the destination MAC address is NOT in the bridge table, it is
assumed to be local traffic and does NOT cross the bridge.
4. If there is no destination MAC address, as in a broadcast packet,
then the traffic crosses the bridge.

Remember, the whole idea of a bridge is to reduce network (or
wireless) traffic.

With a two port bridge, such decisions are fairly trivial in that all
that needs to be decided is whether to cross or not to cross. With a
switch (more than 2 ports), a decision as to which port needs to be
made. A bridge or switch also needs a little time to make the decode
the header and make a decision, so some buffering (FIFO) is usually
added to each port.

I'm going to ignore the added complexities of a VLAN, spanning tree
algorithm, and WDS repeaters.

Now we introduce a wireless bridge. Let's start with the "simple
bridge" and it's one MAC address. The last thing you want is for
every last lousy packet on your LAN to go out the wireless port on
your router and pollute the airwaves with useless traffic. The simple
wireless bridge works exactly the same way as the wired LAN bridge
exept that it's only concerned about traffic to one computah. The
access point has a table of radio MAC addresses and makes a decision
if the packet has a destination at the other end of the wireless
bridge. Multiple simple bridges are not a problem as the table can
have multiple "ports" or radios. This is the way all of the common
wireless access points and client radios operate. A wireless access
point should really be called a wireless switch.

Just one problem. Each client radio only passes one MAC address to
the access point. If you build a network of PC's behind the client
radio, the wireless access point cannot determine if a given packet is
destined for any of these computahs because the access point MAC
address table only has one table entry for the client radio.

To connect two networks together, a wireless transparent bridge is
needed. It's exactly the same as a wired bridge, with its MAC address
table, except that the table is now duplicated at each end of the
bridge. Every time a new MAC address appears on one end of the
bridge, the information has to be added to the table on the other end.
The protocol for doing this is proprietary by manufacturer, which is
why mixing different radio types is a bad idea. The size of the MAC
address tables is also limited in many bridges. The cheapo bridges
are 31 MAC addresses, while the fancy one's (Proxim, Alvarion) can
handle about 2000 or more.

So, why can't you just take two access points, aim them at each other,
and use them to bridge two networks? Well, they can but they lack
support for duplicating the bridge table entries at each end. All the
hardware and most of the software is there, but without a bridging
table protcol, the common access point can only deal with one MAC
address per radio.

That leaves us with your original question, which reduces down to why
can't I pile a bunch of MAC addresses behind a simple bridge (client
radio) and use it to connect two LAN's together though a single MAC
address? You could if the access point was able to store MAC
addresses for the destination PC's. 802.11 will encapsulate the 802.3
ethernet packets. The bridge will see only one of the encapsulated
MAC addresses, and only one computah will be able to communicate.
Were it not for the encapsulation of MAC addresses, it would be
possible.

I'm not sure how the "game adapters" and other bridges handle the
multiple computahs. My guess(tm) is that they expose the encapsulated
source MAC address in the 802.11 header, which makes the traffic look
like multiple client radios. The common access point can easily
handle multiple radios. Again, I'm not sure about this and need to so
some wireless sniffing to be sure (yet another project).


--
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 Fri, 08 Oct 2004 10:53:26 -0700, John . <(E-Mail Removed)> wrote:
>
>>Jeff Liebermann <(E-Mail Removed)> wrote:
>>
>>>On Thu, 07 Oct 2004 13:42:22 -0700, John . <(E-Mail Removed)> wrote:
>>>
>>>>From the DLink documentation I can't determine if the DWL-G810 bridge
>>>>can be used to interconnect 2 wired Lans into one?
>>>
>>>No. One device, one MAC address, and one badly written data sheet.
>
>>Maybe I misstated my question, but wouldn't ONLY ONE mac address be
>>passed between two DWL-G810's, the mac of the bridge? Even though
>>each wired LAN in two separate buildings has 5 or 6 PC's, wouldn't two
>>DWL-G810's just be passing traffic to/through the other corresponding
>>bridge?
>>
>>DWLG810--pc1--pc2--pc3==>switch (all cat5e)
>>+
>>+
>>antennas
>>+
>>+
>>DWLG810--pc4--pc5--pc6==>switch (all cat5e)
>>
>>Does this work?
>
>Nope. The problem is the type of bridge. Again, I'm guessing that
>the DWL-G810+ is a "imple bridge and not a transparent bridge. It's
>difficult to tell from the data sheet. The difference is that a
>simple bridge only deals with one MAC address, while the transparent
>bridge or "network bridge" is designed to connect two networks
>together as in your ascii drawing.
>
>Reminder: bridges deal with MAC addresses, not IP addresses. Let's
>start with a wired LAN bridge. (Incidentally, a switch is a bridge
>with more than 2 ports.) The wired bridge builds a table of MAC
>addresses that it hears on each port. It looks something like:
> Address Port
> MAC1 1
> MAC2 2
> MAC3 1
> MAC4 2
> (...)
> MAC30 2
> MAC31 1
>For convenience I decided the odd MAC addresses would be plugged into
>port 1, while the even MAC addresses in port 2. The 802.3 ethernet
>MAC address header includes the source and destination MAC address of
>each packet. The source address is used to populate the table, while
>the destination address is used to determine which port it needs to
>traverse.
>
>bridging decision time:
>1. If the destination MAC address is in the bridge table, the packet
>crosses the bridge.
>2. If the destination MAC address is in the bridge table, but on the
>same port as the originating MAC address, the packet does NOT cross
>thr bridge (because it has nowhere to go).
>3. If the destination MAC address is NOT in the bridge table, it is
>assumed to be local traffic and does NOT cross the bridge.
>4. If there is no destination MAC address, as in a broadcast packet,
>then the traffic crosses the bridge.
>
>Remember, the whole idea of a bridge is to reduce network (or
>wireless) traffic.
>
>With a two port bridge, such decisions are fairly trivial in that all
>that needs to be decided is whether to cross or not to cross. With a
>switch (more than 2 ports), a decision as to which port needs to be
>made. A bridge or switch also needs a little time to make the decode
>the header and make a decision, so some buffering (FIFO) is usually
>added to each port.
>
>I'm going to ignore the added complexities of a VLAN, spanning tree
>algorithm, and WDS repeaters.
>
>Now we introduce a wireless bridge. Let's start with the "simple
>bridge" and it's one MAC address. The last thing you want is for
>every last lousy packet on your LAN to go out the wireless port on
>your router and pollute the airwaves with useless traffic. The simple
>wireless bridge works exactly the same way as the wired LAN bridge
>exept that it's only concerned about traffic to one computah. The
>access point has a table of radio MAC addresses and makes a decision
>if the packet has a destination at the other end of the wireless
>bridge. Multiple simple bridges are not a problem as the table can
>have multiple "ports" or radios. This is the way all of the common
>wireless access points and client radios operate. A wireless access
>point should really be called a wireless switch.
>
>Just one problem. Each client radio only passes one MAC address to
>the access point. If you build a network of PC's behind the client
>radio, the wireless access point cannot determine if a given packet is
>destined for any of these computahs because the access point MAC
>address table only has one table entry for the client radio.
>
>To connect two networks together, a wireless transparent bridge is
>needed. It's exactly the same as a wired bridge, with its MAC address
>table, except that the table is now duplicated at each end of the
>bridge. Every time a new MAC address appears on one end of the
>bridge, the information has to be added to the table on the other end.
>The protocol for doing this is proprietary by manufacturer, which is
>why mixing different radio types is a bad idea. The size of the MAC
>address tables is also limited in many bridges. The cheapo bridges
>are 31 MAC addresses, while the fancy one's (Proxim, Alvarion) can
>handle about 2000 or more.
>
>So, why can't you just take two access points, aim them at each other,
>and use them to bridge two networks? Well, they can but they lack
>support for duplicating the bridge table entries at each end. All the
>hardware and most of the software is there, but without a bridging
>table protcol, the common access point can only deal with one MAC
>address per radio.
>
>That leaves us with your original question, which reduces down to why
>can't I pile a bunch of MAC addresses behind a simple bridge (client
>radio) and use it to connect two LAN's together though a single MAC
>address? You could if the access point was able to store MAC
>addresses for the destination PC's. 802.11 will encapsulate the 802.3
>ethernet packets. The bridge will see only one of the encapsulated
>MAC addresses, and only one computah will be able to communicate.
>Were it not for the encapsulation of MAC addresses, it would be
>possible.
>
>I'm not sure how the "game adapters" and other bridges handle the
>multiple computahs. My guess(tm) is that they expose the encapsulated
>source MAC address in the 802.11 header, which makes the traffic look
>like multiple client radios. The common access point can easily
>handle multiple radios. Again, I'm not sure about this and need to so
>some wireless sniffing to be sure (yet another project).

Jeff, thanks for your complete exhaustive explanation. It really
really too bad that manufacturers don't more fully explain their
equipment.

My goal was to replace an older pair of DLink DWL-900+ (b mode)
bridges operating in one to one bridge mode. It was fine
interconnected two small wired lans (about 4 PC's each) into one
network neighborhood.

I just replaced the DLink's with a pair of Netgear WGE101 (g mode)
bridges. To get the Netgear bridges to work, I had to set them to
ad-hoc mode with WEP security.

It's working, but I have an uncanny feeling it's not a true
transparent bridge. I could easily see all the shared folders from
both lans, but had trouble with Internet access through the
router/switch that is on one LAN only.

There's very little setup with the Netgear, so it's hard to see what's
happening.

BTW, qcheck throughput went from about 4.5 mbps actual throughput, to
11-12 mbps actual throughput.

Except for the ad hoc mode strangeness, it seems to work.

john

On Sat, 09 Oct 2004 19:48:58 -0700, John . <(E-Mail Removed)> wrote:

>Jeff, thanks for your complete exhaustive explanation. It really
>really too bad that manufacturers don't more fully explain their
>equipment.

Yep. Last month I attended a meeting where such things were
discussed. The consensus was that advanced technical data would
"confuse" the typical customer and would be detrimental to sales. My
past experience confirms this effect. The more technobabble included
in the sales and installation literature, the more problems. If the
goal were to keep the support phone from ringing, most manufacturers
would supply zero technical information. Sorry.

>My goal was to replace an older pair of DLink DWL-900+ (b mode)
>bridges operating in one to one bridge mode. It was fine
>interconnected two small wired lans (about 4 PC's each) into one
>network neighborhood.

The DWL-900AP+ does 22Mbits/sec quite reliably if you turn off the 4x
mode.

http://support.dlink.com/techtool/DW...v_perform.html
(bottom of page). The Rev C incantation will do 802.11g speeds.
Unfortunatly, both will only bridge 31 MAC addresses. That's fine for
4 PC's at each end. I have several pairs of these at customers.

Dumb question: Why would you wanna replace a wireless bridge with one
that offers no additional features or improvements? More
specifically, what problem are you trying to solve?

>I just replaced the DLink's with a pair of Netgear WGE101 (g mode)
>bridges. To get the Netgear bridges to work, I had to set them to
>ad-hoc mode with WEP security.

http://www.netgear.com/products/details/WGE101.php

I guess that's correct. A point to point bridge sorta kinda operates
in ad-hoc mode. You would use the infrastructure mode if you had a
central access point connected to an internet connection and a bunch
of random client radios accessing the internet through it. However,
for a point to point transparent bridge, ad-hoc should work.

I just slogged through the manual at:
ftp://downloads.netgear.com/files/wge101_ref_manual.pdf
Well, at least it has a signal strength indicator. Unfortunately, it
doesn't have a display of a bridging table to see who's connected.
However, it doesn't look like a typical wireless transparent bridge
(such as the DWL-900AP+). For example, there's no way to filter by
MAC address, manually set the exact speed, or deliver SNMP traps or
alarms. No WPA encrytion. No clue how many MAC addresses it can
bridge. I wouldn't call this box much of an improvement. It would
make a nice "game adapter" but I suspect it might be lacking for
bridging two networks. (Disclaimer: I haven't played with it so I may
be totally wrong).

>It's working, but I have an uncanny feeling it's not a true
>transparent bridge. I could easily see all the shared folders from
>both lans, but had trouble with Internet access through the
>router/switch that is on one LAN only.

What kind of trouble? Be specific.

If it's a real live genuine trasparent bridge, then methinks you
should be able to ping all the IP addresses on the other side of the
bridge, and then immediately run:
arp -a
to display the MAC address table showing BOTH sides of the bridge. I
don't have an easy way to test this right now, but suspect that it
should be possible. If it's a single MAC address simple wireless
bridge, you'll only see the MAC address of the bridge radio from the
far end.

Another way to describe the operation of a transparent wireless
ethernet bridge is that it should operate EXACTLY as if an ordinary
ethernet switch box were inserted in place of the two wireless bridge
boxes.

>There's very little setup with the Netgear, so it's hard to see what's
>happening.

That's intentional. The more you know, the more questions you'll ask,
and the more you'll complain. Can't have that happen. What's scarey
is that some of these boxes have well hidden VTAM diagnostic ports the
belch LOTS of information (if you grok hexadecimal). It gets used
during development and troubleshooting, but remain inaccessible to the
customers. You can often find a the connector in the block diagrams
on the FCC ID web pages or just by snooping around the board.
Something like this:
http://www.maxim-ic.com/appnotes.cfm...te_number/1989

>BTW, qcheck throughput went from about 4.5 mbps actual throughput, to
>11-12 mbps actual throughput.

Distance? Antennas? I'm getting about 10-12Mbits/sec thruput with
pairs of DWL-900AP+ bridge radios using mostly 8dBi patch antennas at
ranges between 150ft to 1500ft. However, I had to disable the flakey
4x mode to make it happen. I woudn't give up on the DWL-900AP+ radios
quite yet.

Oh, if you're using external antennas with pigtails, there a real
problem with the SMA plugs not bottoming properly on the DWL-900AP+
panel mounted SMA receptacle. Unscrew the SMA nut, remove the gold
lockwasher, and replace the nut. The connector will now fit snuggly.

>Except for the ad hoc mode strangeness, it seems to work.

In this case, all ad-hoc means is that there's no controlling access
point to deal with cts/rts flow control and system management.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice http://www.LearnByDestroying.com
# (E-Mail Removed)
# 831.421.6491 digital_pager (E-Mail Removed) AE6KS