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Improving Wireless Network


What I have is a 3-storey building. Currently, my 802.11g signal barely makes it to the 2nd floor (I have a wireless router/modem on the ground floor).

I'd like to improve this and thought of connecting a Linksys WRT54GL to my modem and attach 2 high gain antennas to the WRT54GL.

However, I also need at least one RJ45 port for an ethernet connection on the second floor, so I then thought of keeping my existing wireless router on the ground floor and using the WRT54GL on the 2nd floor in some type of bridge mode.

I don't think I'm fully clear on the terminology/functionality though. What exactly do I need? A bridge, AP, wireless extender/repeater, WDS, or a combination of these?

Also, any recommendations for products would be useful (I heard the WRT54GL was fairly good). My supplier stocks Linksys, Belkin, D-Link, Buffalo, Cisco, Netgear, HP, Zyxel and 3Com....

My existing wireless router by the way is a D-Link DSL-2740B-UK.
Julian Matz
Julian Matz
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High gain antennaes improve signal on a horizontal plane, but limit it in all other directions. Think flashlight vs. bare light bulb. It won't help you here.

Cisco, 3Com, D-link (when you don't get their bottom-line stuff) are good brands. Linksys is very good but their consumer line of products are getting worse and worse. Buffalo, Netgear and Belkin are garbage in my opinion. I don't have experience with the others.

Wireless range extenders I find are terribly ineffective and unreliable, especially on wireless networks that have security enabled. I stay as far away from them as possible. Examples:

Router - Handles the assignment of IP addresses to computers, and handles all LAN <-> Internet communication. Also handles the firewall and security and port forwarding.

Switch / Hub - Handles all LAN <-> LAN communication. Any data coming in on one port gets sent out another port depending on where it was headed. These can be daisy chained together,  as long as you're careful to avoid "loops" in the connections.

AP (Wireless Access Point) - It's a switch, but instead of having physical ports, computers connect wirelessly instead. In theory yo ucan have several AP's all using the same SSID (wireless network ID). However, I find with consumer devices this is hit or miss. It's more reliable to give each one it's own ID.

Wireless Bridge - connects two routers together wirelessly, making them part of the same network, in order to provide wired connectivity at a remote location. Great for, say, bridging the network of two independant buildings together. Not really what you want.

Wireless Repeater/Extender - Listens for a wireless signal, and then immediately rebroadcasts it. They must be far enough away from the AP that they don't interfere with the signal, yet close enough that they hear the signal okay. This means there is ALWAYS a "confusion zone"  right in the middle where computers hear BOTH the AP, and then the extender a few milliseconds later. Yuck.

Most consumer devices you see on the market are a *combination* of the above devices. For example, the WRT54GL (http://www.amazon.ca/Linksys-Cisco-WRT54GL-Wireless-G-Broadband-Compatible/dp/B000BTL0OA) is 1) A router, 2) A four port switch, 3) A wireless AP, all rolled into one. Most of these devices you can turn OFF the router functionality and turn the device into a dumb switch/AP.

So what do you want? Probably you want something like the image attached. One dedicated router which connects to the internet. Then you have separate "AP" devices which connect via lan cables to the router. Each AP is on a different floor, each has it's own SSID.

For your router, use a good quality router that is ONLY a router. The Linksys RV082 is my pick. It's pricy, but you'll never need to buy another one again. It is a dedicated router with 8 ports, and 64mb or ram. If you have more than 10 computers on your network, it is vital that you have a good strong router at the core, because almost all packets will flow through this router and it will be under considerable strain.

For your AP's use either the WRT54GL's, or use the WRT54GS (the speedbooster model of the linksys WRT line). Technically almost any wireless router will work so long as you can disable the DHCP server. These devices will function as APs, and four port switches, giving you wired access to all three floors as well. Make sure you turn off the DHCP server on them so that they function as switches/APs rather than routers.
There's one kind of device I forgot to talk about in my list above:

Modem - A device that converts your raw internet signal coming into your house into an ethernet signal your router can use on it's "Internet/WAN" port. Example: A DSL router converts your raw phone line signal into an ethernet signal. Again, I warn you that a lot of ISP's will give you a device that is not just a modem, but also a Modem, Router, Switch AND an AP all rolled into one. You have to configure it to be JUST be a modem.

Also, now that I think about it, the Linksys RV082 is a great device, but it's not easy to configure. There's quite a few extra pages of settings because that router has a lot of features. Something like the Linksys BEFSR81 will work just as well.

Finally, all devices on the network must have DIFFERENT IP addresses which are NOT in the range of the router's DHCP server, but are ALL on the same subnet. For linksys routers, the default range for the DHCP server is, and all the routers by default have the IP You will have to a) change the IP address for each AP to a different number, e.g., etc, THEN b) disable the DHCP server, THEN c) Plug it into the rest of your network and test.

When connecting your APs to your network, do not use the wan/internet port. You connect the AP to the main router via a normal cable by plugging the cable into a normal port on the router, and a normal port on the AP. No crossover cables needed. No special settings needed except turning off the DHCP server on the AP. The wan/internet port should ONLY be used by the main router to connect to your internet.

One last comment, then I'll shut up I promise ;)

In a network setup like this, you might be wondering how you handle port forwarding and static IP addresses (E.g. setting up a machine for bittorrent, gaming etc). ALL of your port forwarding settings are done on the MAIN ROUTER. All of the AP's are just "dumb devices" that route packets. They should not have any special settings set except that their dhcp server is turned off, and their IP address is configured.

Your computers can have static IP addresses like normal, so long as they fall within a range that is NOT withing the dhcp server's range on your router, and IS on the same subnet. E.g. make the IP address for static computers in the range of  If you buy a high quality router, it will have a feature called "Static DHCP", which will assign the SAME IP address to specific computers on your network every time. That way you never have to hard code IP settings into individual computers. Awesomeness.
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Julian MatzAuthor Commented:
Thanks for the detailed infos!

It sounds like what I want so is a wireless bridge.

My ADSL Internet connection comes in on Floor 1 and I'd like to avoid cables going up to the other floors if at all possible. For the time being anyway. I may be able to upgrade at a later stage and have a cable installed.

I currently have 5-6 clients and need capacity for about 8-10 max. Floor 3 is not _that_ important, but definitely need a decent connection on Floor 2.

Also, I need at least one or two ethernet ports on Floor 2, so in other words:

WLAN (Floor 1) --> WLAN (Floor 2) --> Ethernet (Floor 2)

Julian MatzAuthor Commented:
Apart from the D-Link DSL-2740B, I also have a DSL modem/router (non-wireless) with one ethernet port that I got from the provider. I was wondering if I should turn this into a modem-only device and got infos on how to do that here: http:/Q_24148151.html

So do you think it would be better to have a setup like this? :

ADSL -> modem -> router/WAP/DHCP server

... rather than:

ADSL -> all-one-device (modem/router/WAP)

I understand the best scenario would be:
ADSL -> modem -> dedicated router -> AP
... but I'd imagine one of latter would do too? Or would there be a big difference?
I'm not too sure about that. Think of wireless bridges as the "inverse" of a wireless AP. Rather than being a device that connects a bunch of wireless devices to a wired network, it is a device that lets wired computers connect to a remote wireless network. Computers plug into the bridge via cables. As far as the computers are concerned they are connected via lines, but behind the scenes the bridge is actually communicating with a wireless network. See the attached diagram.

This means that the bridge needs good a wireless signal to an existing AP on another floor. You could then maybe connect another AP to that bridge. The WRT54GL (linux) routers use third party firmware and support a bridge mode, but once it's in bridge mode, it is no longer an access point. It's a bridge.

Seriously, consider just drilling through the ceiling. It will make life a lot easier.
whoops forgot diagram. see attached.

You could conceivable attach ANOTHER access point to your wireless bridge.... but that's getting unnecessarily complex and expensive.
Julian MatzAuthor Commented:
"impenetrable pit of doom" - LOL

Ok, I'll see what I can do about the cabling. I do have the cable. I suppose it's just having to drill etc.

So do you think it's better to have 3 devices behind the internet connection as opposed to 2 of 3 - i.e. modem -> router -> AP ?
Let me redraw the diagram I suggested in my first post to put the important stuff on the first floor instead of the second.

You still will definately want to run a wire up between the floors to connect the two linksys AP's to the d-link router. It's important that there are as few wireless hops in your network as possible or you'll have nothing but headaches.

>>So do you think it's better to have 3 devices behind the internet connection as opposed to 2 of 3 - i.e. modem -> router -> AP ?

Nah, it doesn't make a difference. In reality the d-link is already four device layers deep, because it's actually several devices combined together. It's just a matter of how many switches the packets have to hop through to get from one part of your network to another. Here's the datapath from the internet, to a third floor wireless laptop:

                    D-LINK                                   LINKSYS1        LINKSYS2                   LAPTOP    
[[[modem->router->firewall->switch]]]--->[[[switch]]]-->[[[switch->WAP]]]-->[[[WLAN Card]]]

The more devices you have, the more hops you need to do, the more places that the network can fail. You want to minimize the number of hops. In the example above, and in the picture I just posted, you'll see that I have the third floor linksys connected to the second foor linksys. Ideally, both linksys devices should go straight to the d-link router. If that's possible, do it, Then the datapath becomes:

                    D-LINK                                        LINKSYS2                   LAPTOP    
[[[modem->router->firewall->switch]]]--->[[[switch->WAP]]]-->[[[WLAN Card]]]
One final comment - D-Link devices by default have IP address Linksys devices by default have the IP address You must decide on a subnet (the third number), and all devices must share it, otherwise computers on the different subnets won't be able to talk to each other.

My suggestion:

      d-link router:
      linksys #1:
      linksys #2:
      dynamic IP computers:        
      static IP computers / devices:

I'll put this in the other question aswell...

You want:

adsl modem (bridge mode) <------->(any wirless router - linksys will do) <--- ( ( ( wireless ) ) )--->(wireless bridge with built in ethernet switch) <-----> PC's.

You might also want to look into powerline networking. Basicly instead of transmitting the data wirelessly (which can be subject to interferance from microwaves/etc/etc/ walls/ whatever, it transmits over the cables in your electrical wiring. (it uses the power wiring in the power outlet system of your building to conduct the communications signaling). it would look like this:

adsl modem (bridged) <--->wired linksys router<--->Powerline bridge<---power cables--->Powerline bridge<--->switch<--->PC's.
Concept picture:

For example, a pair of these:

I've tried powerline networking in at least three different occasions and I've been disappointed every time. They're unreliable, and while they advertise 200mbps, it is the theoretical maximum. I've never seen more than about 50mbps and that bandwidth is shared by the entire network, not just a single computer. The problem is that the cables used for electricity are just not the same grade as ethernet wires. No twisted pairs, no shielding, no protection, and every in-wall power cable, every outlet, every extension cord becomes an antennae that puts noise on the network.

Then, because the lines are used for power as well, any electrical device plugged into any outlet in the building which sends feedback signals back into the powerline will interfere as well. Most AC motors do this. This means vacuum cleaners, overhead fans, hair dryers, compressors, sometimes even your furnace, or dryer, or air conditioner will cause problems depending on how old they are and their quality in their design. Manufacturers of cheap appliances do not put much effor into their designs to prevent minute feedback back into the power system. Since you can't realistically control what people in the building plug into the power outlets, one person will plug a cheap fan into the power outlet this summer and the whole network willl go down every time he turns it on. You'll spend months trying to figure out what the original cause was.

Sorry asklkf, I don't mean to slander you or anything but I've found that powerline networks are as bad as repeaters - they're gimmicks to make life "easier" for a lazy home user. Every time I've used them it has been a disaster.
Agreed; I'm certainly not standing by their "reliability", but for some they are the only option (when you can't touch the walls to fish new cat-5 or cat-6e and there is too much wireless interferance).

If some parallel grid antennas will produce sifficient gain/noise ratios and if they are installed correctly with their axis relatively positioned to eachother, they will outperform powerline every time.

But, it takes either a lot of understanding or an experienced installer to position the antenna's where they will have consistantly high SNR's and be able to point out related devices that should be avoided (microwaves, phones... I'm not going to go through the list... pace makers, kites with keys hanging on the string... etc...).

It's an option that CAN be appropriate; I appologise if I came off as saying it "should" be appropriate.

the ultimate "should" would be: "RUN SOME ETHERNET CABLE THROUGH THE WALLS." but this isn't soemthing everyone wants to do.
Julian MatzAuthor Commented:
Ok, I got myself 1000ft of CAT5e cable and had an electrician in last Saturday to try and run some of the cable from the ground floor to the 1st floor. After a while of drilling he had to give up unfortunately because he said it could get too messy (all concrete walls and ceilings). I didn't want to do any irreversable "damage" being as I don't own the property.

So I ended up having to run the cable along the surface with cable clips. I now have a single cable going up which is connected to an access point. I presume I'll be able to use a hub in between for more LAN connections.

I appreciate all the advice and help on this!

I'm now faced with another problem - I'm trying to figure out how to design my network. I'm not happy with my router/modem on the ground floor. I think it might be faulty and keeps dropping connections so I'll need to replace that anyway. I also would like to use a proxy server though and have a couple of options as well as questions. I'm going to post a new question for this, so if you want to have a look, please feel free :)

(I'll close this one shortly).

on the dropping connections thing:

Login to your router, check if you have stateful packet inspection (might be called "SPI", "Deep Packet Inspection" or "stateful Firewall" or something very close to that). If this is generating log errors at the same time that your router is dropping connections then it's intentionally being dropped to prevent attacks.

(this is just a random guess).

Julian MatzAuthor Commented:
Thanks again.

Regarding the router dropping connections - I'm pretty sure it's a hardware fault as the router actually disconnects wireless clients from the access point as well as completely closing the actual connection with the ISP at the same time.

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