How does repeater work?

20 Jan 2009 3:22 AM

njem

I work with networks and wireless a lot and know electronics. I've
always avoided using repeaters just by using stronger antennas and
such. I just setup my first repeater. I was surprised that it used the
same channel and SSID. I expected it would read the signal from the
wireless router on one channel, and then retransmit it on another
channel probably with a different SSID. Then systems that connect just
pick whichever signal is stronger and connect to that.

The docs with the repeater said that all devices should be on the same
channel and have the same SSID, I guess as in if you have a big area
and half a dozen repeaters. And you can wander from place to place and
pick up whichever one is closest.

Maybe it makes sense that it can retransmit on the same channel, much
like two-way devices like cordless phones work on a given channel. But
having multiple units on one channel is confusing. And how does a
computer know which one it's connecting to? Is the mac address
broadcasting along with the SSID and the wireless cards are
identifying that?

Unfortunately my tools added to the confusion. Even when I was in
range of both devices, the repeater being stronger, the Windows tool
showed one instance, and would only let me connect to the generic
SSID, not a specific instance. My wireless card tool showed two
instances, one stronger than the other, but would only let me connect
to the SSID in general, not choose a specific one. If I watched the
signal graph I had a strong signal. If I turned the repeater off and
on the laptop would stay connected but show the signal drop low, then
come back up. Cool, but confusing.

Anybody know of a good paper on how repeaters do this stuff?

Thanks

20 Jan 2009 4:23 AM

Jack (MS, MVP-Networking)

Hi
The Repeaters that cost bellow $500 have only one Radio.
This Radio Flip-Flops between Receiving form the source, and then
disconnecting from the source and transmitting further.
The expensive Repeaters has two Radios one to connect to the source and one
to transmit further.
You can create an Inexpensive two Radios Repeater by buying two inexpensive
Access Points, set one as Client Wireless, and the second as regular AP,
connect the two one to the other with short crossover cable.
Wireless Modes - http://www.ezlan.net/Wireless_Modes.html
Wireless Bridging - http://www.ezlan.net/bridging.html
Jack (MS, MVP-Networking)

Show quoteHide quote

"njem" <n***@q.com> wrote in message
news:21973a50-8533-41f5-b2d3-2a1071982adc@o40g2000prn.googlegroups.com...
>I work with networks and wireless a lot and know electronics. I've
> always avoided using repeaters just by using stronger antennas and
> such. I just setup my first repeater. I was surprised that it used the
> same channel and SSID. I expected it would read the signal from the
> wireless router on one channel, and then retransmit it on another
> channel probably with a different SSID. Then systems that connect just
> pick whichever signal is stronger and connect to that.
>
> The docs with the repeater said that all devices should be on the same
> channel and have the same SSID, I guess as in if you have a big area
> and half a dozen repeaters. And you can wander from place to place and
> pick up whichever one is closest.
>
> Maybe it makes sense that it can retransmit on the same channel, much
> like two-way devices like cordless phones work on a given channel. But
> having multiple units on one channel is confusing. And how does a
> computer know which one it's connecting to? Is the mac address
> broadcasting along with the SSID and the wireless cards are
> identifying that?
>
> Unfortunately my tools added to the confusion. Even when I was in
> range of both devices, the repeater being stronger, the Windows tool
> showed one instance, and would only let me connect to the generic
> SSID, not a specific instance. My wireless card tool showed two
> instances, one stronger than the other, but would only let me connect
> to the SSID in general, not choose a specific one. If I watched the
> signal graph I had a strong signal. If I turned the repeater off and
> on the laptop would stay connected but show the signal drop low, then
> come back up. Cool, but confusing.
>
> Anybody know of a good paper on how repeaters do this stuff?
>
> Thanks

20 Jan 2009 5:12 AM

njem

> Wireless Modes -http://www.ezlan.net/Wireless_Modes.html
> Wireless Bridging -http://www.ezlan.net/bridging.html

Thanks. Much good info to digest.

20 Jan 2009 3:27 PM

njem

> This Radio Flip-Flops between Receiving form the source, and then
> disconnecting from the source and transmitting further.

Doesn't the repeater transmitting on the same channel as the source
conflict with the source, or is that deeper detail than they reveal?

Thanks

20 Jan 2009 8:58 PM

Jack (MVP-Networking).

Hi
It does not conflicts since multi Wireless devices can transmit on the
channel.
Each transmittion has its own packet characteristic (even if the channel and
the SSID are the same) so the Wireless client can decide which one they
choose to connect to.
Jack (MS, MVP-Networking)

Show quoteHide quote

"njem" <n***@q.com> wrote in message
news:302e960f-ee61-40a1-acc4-0a8ecc437911@g1g2000pra.googlegroups.com...
>> This Radio Flip-Flops between Receiving form the source, and then
>> disconnecting from the source and transmitting further.
>
> Doesn't the repeater transmitting on the same channel as the source
> conflict with the source, or is that deeper detail than they reveal?
>
> Thanks

20 Jan 2009 11:00 PM

GbH

Show quote Hide quote

"Jack (MVP-Networking)." <j***@discussiongroup.com> wrote in message
news:#p1pxH0eJHA.1528@TK2MSFTNGP03.phx.gbl...
> Hi
> It does not conflicts since multi Wireless devices can transmit on the
> channel.
> Each transmittion has its own packet characteristic (even if the
> channel and the SSID are the same) so the Wireless client can decide
> which one they choose to connect to.
> Jack (MS, MVP-Networking)
>
> "njem" <n***@q.com> wrote in message
> news:302e960f-ee61-40a1-acc4-0a8ecc437911@g1g2000pra.googlegroups.com...
>>> This Radio Flip-Flops between Receiving form the source, and then
>>> disconnecting from the source and transmitting further.
>>
>> Doesn't the repeater transmitting on the same channel as the source
>> conflict with the source, or is that deeper detail than they reveal?
>>
>> Thanks

Curious, I wonder how RF jamming works then?

--
Wisdom and experience come with age, they say, but I wish I could
remember the darn question