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In my home I've got a wireless router that does all the work and because of the lack of signal, I have bought another device that can act either as an Access Point or as a Universal Repeater. I was wondering, what is the difference between the two modes?

I thought that Repeater would allow me to have only one wireless network, e.g. ESSID=MyHome, and laptops and phones automatically using whichever of the router and access point are closer / have better signal. But that doesn't seem to be the case - AP's manual suggests that the repeated wifi network has another name, like MyRepeatedHome.

Intuitively, that doesn't seem like "repeating" to me - it looks like simply setting up another Access Point, so what's the difference? And can I achieve the ideal setup where only one ESSID is visible and my home devices smartly switch between the router / access point?

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A wireless access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth or related standards. It is basically just a source for wireless Internet connections.

The pure definition for an access point is distinct from that of a router : A router will also give such services as NAT routing, DHCP client/server, PPPoE client, etc. and will therefore create a network that consists of a unified IP addresses segment. That said, I do not believe that in access point mode your router will not provide these services.

A repeater is just a very normal client which, at the same time, can also be an access point, independent of the SSID and type of encryption used. A Universal Wireless Repeater is a device that you can place anywhere and it will wirelessly repeat the strongest signal, onto another wireless network (with or without security). As you have found, it implies the existence of two networks.

However, there is a bit of confusion in the terminology, as it is also normal to say that a wireless repeater extends the range of the local wireless network. These have also been called wireless expanders or range extenders.

Bridging is a forwarding technique used in packet-switched computer networks. Unlike routing, bridging makes no assumptions about where in a network a particular address is located. It is is only used in local area networks. A bridge uses a dynamically-built forwarding database to send frames across network segments. It is basically used to virtually unify multiple network segments, by forwarding messages from one network to another with appropriate IP address translations.

In conclusion: It seems that the the people who wrote the manual and technical specs for your router should also have had a better education as regarding these terms.

[EDIT]

I have looked at the manual of the Edimax. This is not a very recent model, but there is no reason for it not to function correctly. The manual says :

"Universal Repeater Mode" provides the function to act as AP client and AP at the same time. It can use AP client function to connect to a Root AP and use AP function to service all wireless stations within its coverage. All the stations within the coverage of this access point can be bridged to the Root AP. “Universal Repeater Mode” is very convenient to extend the coverage of your wireless network.

It seems to me that "Universal Repeater Mode" is meant to bridge between two wireless networks, and therefore looks like the mode you want use, if you want it to connect to the router by wireless. However, I am still a bit worried since the image in the manual does not contain enough info to connect to the router, but that may be specified on another screen.

If "Universal Repeater Mode" does not work, the next to try is "AP Bridge Mode".

The text in the manual is very sparse and hard to understand. You will simply have to experiment with "Universal Repeater Mode" and "AP Bridge Mode" to see what exactly they do. It is quite possible that the shortness of the text comes from the ignorance of the documentation writer, and hence the exact terms he used should not be taken too seriously.

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Does repeater mode imply that the repeated signal must be wireless as you suggest? Because I have a wired connection between the router and the AP. If the signal can be wired, what's the difference between AP and a repeater? So maybe I want a range extender that supports wired connection between the main router and the additional device? Or do I need network bridging? –  Borek Oct 1 '11 at 17:07
    
The technical terms are not used in an exact manner. It all depends on the hardware and firmware, so don't trust the written terms - read instead what the black box can do. I would say that with a wired input and wireless output a box is an AP. With both wireless, it is more of a repeater. But the borders are thin, and many times a given box can do more than one role. –  harrymc Oct 1 '11 at 17:36
1  
If you are not sure what to buy, go into a computer hardware shop, describe your setup and ask for a recommendation. Trying to judge by the terminology may be misleading. Ensure that if the vender makes a mistake you can ask for a replacement. –  harrymc Oct 1 '11 at 18:43
    
The devices are Netgear WNDR3700 (main router) and Edimax EW 7209apg. I'd like to hear a generic answer because I have spent so many hours trying to figure out the setup that I think I should really try to understand what's going on. –  Borek Oct 1 '11 at 21:47
    
See my edit above. –  harrymc Oct 2 '11 at 10:58
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I'm too late on the scene to be helpful to the OP, but I had similar problems that stopped me from getting my Edimax EW-7416APn v2 AP in universal repeater mode working, and hopefully some of that experience will be useful to others.

The Edimax AP manual was indeed very poor, but Edimax have now posted an extra manual specifically for UR setup on their product support website -- I guess they were deluged with complaints about the original crappy documentation! This was the key to me getting the universal repeater mode set up correctly.

The extra setup guide is still not obvious to find: go to the product support page on the Edimax website, and in the FAQ section the final question "How to setup EW-7416APn V2 as a repeater (range extender) manually?" is linked to a PDF specifically answering that question. This document gives the necessary specifics about setting exactly the same security (type and password), channel, IP range, etc. and making sure that only the base router/access point is acting as a DHCP server.

What it still isn't clear enough about is that yes, you can and should use the same name (ESSID) for the network being repeated. The wifi protocol is (sensibly) designed that way, so that multiple physical APs can be used to implement one seamless network, with the attached devices automatically switching between APs depending on signal strength. I found it very useful on my Android phone to use the Wifi Analyser app, which shows the separate physical APs as sub-entries under my network's ESSID, and you can see the strengths varying and the device association switching between the APs as you walk around. On Linux (I just installed a copy of Xubuntu) the nm-tool and iwlist commands give similar useful information.

I also found out some weeks later that the enabled wireless protocols also need to be matched between base station and repeater. The extra setup guide wasn't clear about that either, and allowing the repeater to use a better protocol seemed to work until I got a new laptop with a better network card: at that point I could connect to the network and get a DHCP lease, but no pings or attempted local/internet traffic would work. So if the network being extended is a B+G network then the extender needs to be set to do that too, and not to allow wireless N: my suspicion is that when the extender is asked to use N by the client, it then attempts to do the same to the base AP and (if the base AP doesn't have that capability) fails.

Good luck -- it's certainly good once you've figured it out, but Edimax need to seriously improve the quality (and volume) of their documentation if they don't want to be a source of frustration to everyone who buys one of their products!

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There's an Edimax document that explains their terminology.

Access Point: Is where your device is connected to an adsl VIA A WIRE to a router on one side, and allow other devices to connect to it wirelessly.

AP Client mode, aka Wireless Bridge or Station Infrastructure mode, is where your device is WIRELESSLY connected to a adsl wireless router, and allows another device (think game console) to connect to it only via wire. Your device won't be seen by wireless clients. All it does is "connects" the wired device that's connected to it, via the air, to the wireless router.

Repeater mode - is where your device is connected wirelessly to your wireless network, and allows other wireless clients to connect to it. It extends the reach of your wireless network, and will be defined to have the same wireless network name (allowing clients to jump between your device and the original wireless router based on signal strength).

full document is here: http://www.edimax.us/html/Faq/AP-modes.pdf

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