Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Wireless Networking > Theoretical max speed for 802.11g "108" bridge

Reply
Thread Tools

Theoretical max speed for 802.11g "108" bridge

 
 
Gregg Hill
Guest
Posts: n/a
 
      09-10-2006
Hello!,

I need to replace a client's wireless bridge to cover a gap that is roughly
90 feet between buildings (I am a lousy estimator of distance. I thought it
was 300', but I paced it off the other day and it's only about 90'). I took
a close look at their antennas from across the street, and the main
building's Yagi appears to be pointing about six feet over the top of the
receiving Yagi. I think the person who initially installed it used the wrong
antennas for this distance. Since a Yagi has a very narrow beam, I would
expect them to have to be pointing down each other's throats to work well.

This theory also fits what is seen at the site. The remote antenna points
directly at the main one, while the main one shoots over the remote's head.
The data transfer from remote to main is 20Mbps and the transfer from main
to remote is 3Mbps. The current bridge is done using Netgear WG102 units
(two years old) with PoE. The client does not have the password to get into
them to see the settings, and I cannot down the link to reset the units to
default for access unless I go there on a Sunday. Therefore, I want to
replace the equipment with something faster.

Out of curiosity, and before I go with very expensive Proxim (thank you for
the link, Jack!) or Ceragon equipment, I asked Netgear which unit would be
best and they recommended the WAG302, partly because you can use 802.11a to
eliminate a lot of interference. Since they tout this unit as
108Mbps-capable, I asked about the maximum theoretical bridge speed, which
they said would be 54Mbps. I wonder if that is correct. I tried D-Link's
DWL-2100AP set to use 108 and it only bridged at 23Mbps, according to
QCheck. I tried two Linksys WAP54G units and they bridged at 25Mbps, even in
the same room.

I have tested Netgear's 108-rated stuff used in normal fashion with a WGT624
wireless router and a WG511T laptop card, and I get about 76Mbps speed,
better than hard-wired cheap NICs with Realtek chipsets.

Do you know what the theoretical maximum bridge speed would be for 54G and
108G equipment?

Gregg Hill


 
Reply With Quote
 
 
 
 
Jack \(MVP-Networking\).
Guest
Posts: n/a
 
      09-11-2006
Hi

The speed that network devices are market under is the speed of the
electronic circuitry on the device, not the Network's transfer speed.

This page has some functional info. http://www.ezlan.net/net_speed.html

Yagi or not at 90 you get less then what you get at 20

Jack (MVP-Networking).


"Gregg Hill" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hello!,
>
> I need to replace a client's wireless bridge to cover a gap that is
> roughly 90 feet between buildings (I am a lousy estimator of distance. I
> thought it was 300', but I paced it off the other day and it's only about
> 90'). I took a close look at their antennas from across the street, and
> the main building's Yagi appears to be pointing about six feet over the
> top of the receiving Yagi. I think the person who initially installed it
> used the wrong antennas for this distance. Since a Yagi has a very narrow
> beam, I would expect them to have to be pointing down each other's throats
> to work well.
>
> This theory also fits what is seen at the site. The remote antenna points
> directly at the main one, while the main one shoots over the remote's
> head. The data transfer from remote to main is 20Mbps and the transfer
> from main to remote is 3Mbps. The current bridge is done using Netgear
> WG102 units (two years old) with PoE. The client does not have the
> password to get into them to see the settings, and I cannot down the link
> to reset the units to default for access unless I go there on a Sunday.
> Therefore, I want to replace the equipment with something faster.
>
> Out of curiosity, and before I go with very expensive Proxim (thank you
> for the link, Jack!) or Ceragon equipment, I asked Netgear which unit
> would be best and they recommended the WAG302, partly because you can use
> 802.11a to eliminate a lot of interference. Since they tout this unit as
> 108Mbps-capable, I asked about the maximum theoretical bridge speed, which
> they said would be 54Mbps. I wonder if that is correct. I tried D-Link's
> DWL-2100AP set to use 108 and it only bridged at 23Mbps, according to
> QCheck. I tried two Linksys WAP54G units and they bridged at 25Mbps, even
> in the same room.
>
> I have tested Netgear's 108-rated stuff used in normal fashion with a
> WGT624 wireless router and a WG511T laptop card, and I get about 76Mbps
> speed, better than hard-wired cheap NICs with Realtek chipsets.
>
> Do you know what the theoretical maximum bridge speed would be for 54G and
> 108G equipment?
>
> Gregg Hill
>
>



 
Reply With Quote
 
 
 
 
Gregg Hill
Guest
Posts: n/a
 
      09-11-2006
Jack,

When I tested with Linksys WAP54G units, they got 26Mbps in the same room
and 23Mbps bridging across the street 125' away using a 6dbi D-Link internal
antenna on one end and the built-in antennas on the remote end.

I understand that marketed speed and real speed will be different. The same
goes for 100Mbps hard-wired speed marketing vs. real world speed. When using
the Netgear 108-advertised equipment noted in my last post, I got around
75-80 between my wireless laptop and a desktop with an Intel NIC hard-wired,
while a hard-wired Realtek card in another system only got only 38. I popped
a 3Com NIC into that system and got 85.

What I am trying to find out is if bridging can **only** be half the speed
of normal wireless NIC-to-AP speed. Or is it possible to get higher than
half the rated speed?

I wish 802.11n were available in APs that will bridge. The ones I have seen
so far can only be used as an AP, not a bridge.

Thank you for the link. I'll go take a look at it now.

Gregg Hill




"Jack (MVP-Networking)." <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Hi
>
> The speed that network devices are market under is the speed of the
> electronic circuitry on the device, not the Network's transfer speed.
>
> This page has some functional info. http://www.ezlan.net/net_speed.html
>
> Yagi or not at 90 you get less then what you get at 20
>
> Jack (MVP-Networking).
>
>
> "Gregg Hill" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Hello!,
>>
>> I need to replace a client's wireless bridge to cover a gap that is
>> roughly 90 feet between buildings (I am a lousy estimator of distance. I
>> thought it was 300', but I paced it off the other day and it's only about
>> 90'). I took a close look at their antennas from across the street, and
>> the main building's Yagi appears to be pointing about six feet over the
>> top of the receiving Yagi. I think the person who initially installed it
>> used the wrong antennas for this distance. Since a Yagi has a very narrow
>> beam, I would expect them to have to be pointing down each other's
>> throats to work well.
>>
>> This theory also fits what is seen at the site. The remote antenna points
>> directly at the main one, while the main one shoots over the remote's
>> head. The data transfer from remote to main is 20Mbps and the transfer
>> from main to remote is 3Mbps. The current bridge is done using Netgear
>> WG102 units (two years old) with PoE. The client does not have the
>> password to get into them to see the settings, and I cannot down the link
>> to reset the units to default for access unless I go there on a Sunday.
>> Therefore, I want to replace the equipment with something faster.
>>
>> Out of curiosity, and before I go with very expensive Proxim (thank you
>> for the link, Jack!) or Ceragon equipment, I asked Netgear which unit
>> would be best and they recommended the WAG302, partly because you can use
>> 802.11a to eliminate a lot of interference. Since they tout this unit as
>> 108Mbps-capable, I asked about the maximum theoretical bridge speed,
>> which they said would be 54Mbps. I wonder if that is correct. I tried
>> D-Link's DWL-2100AP set to use 108 and it only bridged at 23Mbps,
>> according to QCheck. I tried two Linksys WAP54G units and they bridged at
>> 25Mbps, even in the same room.
>>
>> I have tested Netgear's 108-rated stuff used in normal fashion with a
>> WGT624 wireless router and a WG511T laptop card, and I get about 76Mbps
>> speed, better than hard-wired cheap NICs with Realtek chipsets.
>>
>> Do you know what the theoretical maximum bridge speed would be for 54G
>> and 108G equipment?
>>
>> Gregg Hill
>>
>>

>
>



 
Reply With Quote
 
Gregg Hill
Guest
Posts: n/a
 
      09-13-2006
I meant to say 6dbi D-Link "indoor" antenna and not 6dbi D-Link "internal"
antenna.

Gregg Hill



"Gregg Hill" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Jack,
>
> When I tested with Linksys WAP54G units, they got 26Mbps in the same room
> and 23Mbps bridging across the street 125' away using a 6dbi D-Link
> internal antenna on one end and the built-in antennas on the remote end.
>
> I understand that marketed speed and real speed will be different. The
> same goes for 100Mbps hard-wired speed marketing vs. real world speed.
> When using the Netgear 108-advertised equipment noted in my last post, I
> got around 75-80 between my wireless laptop and a desktop with an Intel
> NIC hard-wired, while a hard-wired Realtek card in another system only got
> only 38. I popped a 3Com NIC into that system and got 85.
>
> What I am trying to find out is if bridging can **only** be half the speed
> of normal wireless NIC-to-AP speed. Or is it possible to get higher than
> half the rated speed?
>
> I wish 802.11n were available in APs that will bridge. The ones I have
> seen so far can only be used as an AP, not a bridge.
>
> Thank you for the link. I'll go take a look at it now.
>
> Gregg Hill
>
>
>
>
> "Jack (MVP-Networking)." <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
>> Hi
>>
>> The speed that network devices are market under is the speed of the
>> electronic circuitry on the device, not the Network's transfer speed.
>>
>> This page has some functional info. http://www.ezlan.net/net_speed.html
>>
>> Yagi or not at 90 you get less then what you get at 20
>>
>> Jack (MVP-Networking).
>>
>>
>> "Gregg Hill" <(E-Mail Removed)> wrote in message
>> news:(E-Mail Removed)...
>>> Hello!,
>>>
>>> I need to replace a client's wireless bridge to cover a gap that is
>>> roughly 90 feet between buildings (I am a lousy estimator of distance. I
>>> thought it was 300', but I paced it off the other day and it's only
>>> about 90'). I took a close look at their antennas from across the
>>> street, and the main building's Yagi appears to be pointing about six
>>> feet over the top of the receiving Yagi. I think the person who
>>> initially installed it used the wrong antennas for this distance. Since
>>> a Yagi has a very narrow beam, I would expect them to have to be
>>> pointing down each other's throats to work well.
>>>
>>> This theory also fits what is seen at the site. The remote antenna
>>> points directly at the main one, while the main one shoots over the
>>> remote's head. The data transfer from remote to main is 20Mbps and the
>>> transfer from main to remote is 3Mbps. The current bridge is done using
>>> Netgear WG102 units (two years old) with PoE. The client does not have
>>> the password to get into them to see the settings, and I cannot down the
>>> link to reset the units to default for access unless I go there on a
>>> Sunday. Therefore, I want to replace the equipment with something
>>> faster.
>>>
>>> Out of curiosity, and before I go with very expensive Proxim (thank you
>>> for the link, Jack!) or Ceragon equipment, I asked Netgear which unit
>>> would be best and they recommended the WAG302, partly because you can
>>> use 802.11a to eliminate a lot of interference. Since they tout this
>>> unit as 108Mbps-capable, I asked about the maximum theoretical bridge
>>> speed, which they said would be 54Mbps. I wonder if that is correct. I
>>> tried D-Link's DWL-2100AP set to use 108 and it only bridged at 23Mbps,
>>> according to QCheck. I tried two Linksys WAP54G units and they bridged
>>> at 25Mbps, even in the same room.
>>>
>>> I have tested Netgear's 108-rated stuff used in normal fashion with a
>>> WGT624 wireless router and a WG511T laptop card, and I get about 76Mbps
>>> speed, better than hard-wired cheap NICs with Realtek chipsets.
>>>
>>> Do you know what the theoretical maximum bridge speed would be for 54G
>>> and 108G equipment?
>>>
>>> Gregg Hill
>>>
>>>

>>
>>

>
>



 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to calculate theoretical max download speed from upload speed (ADSL) ? GraB NZ Computing 5 10-29-2006 10:14 AM
Bridge/workgroup bridge scenario and channels Chris_D Cisco 6 08-05-2005 07:46 AM
good theoretical GUI knowledge Tim Java 4 02-11-2004 01:47 AM
Max Apperture and Max. Shutter Speed Confusion-HELP bhaskar Digital Photography 12 07-22-2003 05:17 PM



Advertisments