Connect two wireless+wired networks wirelessly?

Question

Is there any mode, when wireless device or access point can serve both as access point for clients and as a bridge between two wireless networks?

Like here:

UPDATE

Also I would like to have ONE wireless device (router, AP, etc) in each part of the networks and also want these parts to be independent, i.e. if one AP down, then only it's clients are down, having clients of other AP communicate with each other.

UPDATE 2

Probably the answer is related to so called WDS, which is not standartized.

I don't understand why do remarks below are so often repeated:

1) two radio nodes can't transmit simultaneously

This is not a point because this is true to any Ethernet too. Two wired cards also can't transmit simultaneously.

2) repeater reduces speed twice because it should have time to repeat all it hears

This is also not a point because single Access Point also repeats when connecting two wireless devices. Communicating between two wireless devices with one access point also reduces speed twice

3) it is dangerous to connect something to Internet

Question is unrelated with Internet. We are speaking about LAN.

I am coming to conclusion that it was made a serious design mistake while designing WiFi protocols, because implementing WDS looks straightforward and should be implemented in standard AP protocol.

Answer 1

Ok so there are many ways to do this, but I you should be aware NEVER connect your local network to an AP which is connected to the internet as this would allow people to access your network.

Also make sure you set your Wireless access points 6 channels apart to avoid interferance as they are too close.

So firstly AP's can not communicate with each other wirelessly with consumer grade products, they only communicate with wireless clients, so you would need what is called a "Wireless Bridge" to connect both AP's together.

Here is a brief description on the possible modes you can set with a wireless bridge, obviously you can decide which one fits your needs.

Point to Point

This will connect the two segments using two bridge products, one unit is set to master whilst the other is set to slave.

This is a brief picture

Here is a website link describing how it is setup http://www.tp-link.com/en/article/?faqid=176

Answer 2

This situation is called "Wireless repeater": AP2 talks to AP1 as it's client and shows up under the same BSSID as AP1. The downside is that you cripple the overall bandwidth.

To quote some helpful thoughts from http://forums.whirlpool.net.au/archive/1631183:

There's one important point to understand first before discussing devices. Wireless uses a shared medium, that is a specific radio frequency, only one device can be transmitting at any time otherwise the signals would interfere with each other and could not be understood by anything else. Also, for the same reason a device cannot be sending at the same time it is listening.

And

There's two types of devices that you can use to extend the range of a wireless network. First is a wireless repeater, basically it listens to the frequency being used, whenever it hears something it sends it out again, because it's in a different location to the first station the signal gets sent out further. However, due to the above fact about wireless networks, if you use a repeater the throughput is effectively halved because for each second it spends listening it needs a second to send it, thereby taking twice as long to send data.

Just a side note: Again, only one device can be transmitting at any time. By adding repeaters you are not improving the situation, throughput wise. You are just adding another party which shouts it's stuff through the air. If more parties shout, it's harder to understand anything. The same is true for the power of the Wifi-Signal (think of loudness): Just because you can now shout louder does not improve the general situation. It would be better to make AP2 talk to AP1 over a different medium (cable, powerline, 2nd channel or other AP) and to make the radius of the circle non-overlapping ("reduce the loudness"). I am aware of the fact that sometimes the reality (budget, hardware, locality etc) dictates what you can use.

Read more: http://en.wikipedia.org/wiki/Wireless_repeater