Help Needed-Complex Network Set Up..

[powerleakin]

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Hi. This is actually a picture of my office. Its two separate buildings joined at the middle.

My modem is at B and cannot be moved. I have to place my 802.11n router at A as there's a NAS box there(LAN only). C,E,D,F are PCs which can get coverage from A.

My problem now is I'm lost on how to connect Modem at B to router at A. Running cables over is not preffered, B is 1st floor while A is ground floor. Homeplug is too expensive, plus its 2 different buildings joint at middle, so electrical wiring is different.

My idea is to get a WRT54G DDWRTed and hook it up to the Modem at A. But I understand that if i connect this wirelessly to the 11n router, then the speed of the network is reduced to 11g. I also read some where that the only way to retain 11n is to do something called AP isolation where the 11n router connects to 2 networks. It maintains 11n speed with say Network 1 (All n devices) and at the same time, maintains a 11g connection with 11g router.

So the 11n router must channel all outward packet request from client PCs to the 11g router (which'll forward it to the modem). And other 11g devices should also be able to connect to the the Internet through WRT54G's 11g network.

So this is my idea. The thing is, I don't know whether its too complex or whether it'll actually work. Or whether there is a simpler/easier alternative. Please advise. Thanks.

PS: The 802.11n router I plan to use is D-Link DIR655.

 

[overdrive31]

My idea is to get a WRT54G DDWRTed and hook it up to the Modem at A. But I understand that if i connect this wirelessly to the 11n router, then the speed of the network is reduced to 11g. I also read some where that the only way to retain 11n is to do something called AP isolation where the 11n router connects to 2 networks. It maintains 11n speed with say Network 1 (All n devices) and at the same time, maintains a 11g connection with 11g router.

PS: The 802.11n router I plan to use is D-Link DIR655.

How fast is your internet connection? Slower than 20mbps, then wireless G has got plenty bandwidth to support it. Would then only need the wireless N for LAN side speed(sharing files across local network).

WDS(DD-WRT) would require the WRT54G to be the AP(client mode) not the gateway(connected to modem), because the DIR-655 doesn't support WDS forcing you to use it as the gateway. Only way to make WDS benefit you without losing wireless N bandwidth(only LAN speed) is two WRT54G routers bridged, one at the modem location and the other where you plan to have the wireless N router (DIR-655) which will be the new gateway.

The reason I say you need two WDS routers to be bridged is if you have the N router be gateway and the G router the AP(WDS Client mode) it will need another N router to be connected to G router so to service wireless clients. No matter how you look at it, you will need at least 3 routers if you want to keep bandwidth high.

2 routers w/o WDS, one being N and 1 WDS for client mode = 3 routers no throughput loss, but tricky setup(dual NAT or wireless N needs to become an AP) - not ideal

1 router w/o WDS, 1 WDS for repeat mode(splits that 20mbps throughput in half) = 2 routers, but half G speed(10mbps, slow) and all clients must connect to WDS repeater which is the G router - not ideal.

2 routers w/ WDS bridged, 1 N router as gateway/wireless AP for clients = 3 routers, but optimum setup a WDS wireless ethernet bridge doesn't lose bandwidth and the N router becomes the gateway/AP - perfect!

Using 2.4GHz in all of this you will saturate the frequency band using all 3 non overlapping channels(1,6,11). WDS bridge with 2x Apple base stations via 5GHz N(not sure if it can be done) would free up some room on the 2.4GHz band if there happens to be nearby sources of 2.4GHz that could interfere, as well as keep the entire setup wireless N(no G speed bottleneck if internet is faster than 20mbps).

 

[thiggins]

It would help to know the distances involved and the construction of the buildings, i.e. concrete, wood frame/sheetrock, etc.

Also the speed of your Internet service.

G will give you 20 - 25 Mbps best case. Average speeds with moderate distance will be more like 10 Mbps. That would be from Ethernet port on one router to Ethernet port on the other router. Wireless client associated with the remote AP will see less than half that, i.e. < 5 Mbps. This is because the single radio must receive, then retransmit.

N will give you around 50 - 60 Mbps best case using 20 MHz bandwidth, which is the default and what I recommend in the 2.4 GHz band. Average speed with moderate distance will be more like 20 - 30 Mbps.

I think you're going to want an AP in each building for good coverage. So get two N routers that support WDS bridging / repeating, which will optimize the link speed between the two buildings. Then see if speed are satisfactory. If it isn't, you either then add 11g APs in the buildings as needed, or migrate your business client machines to N.

The DIR-655 doesn't do WDS. Routers that do, include the Apple Airport Extremes, ASUS RT-N16 and RT-N13U

 

[powerleakin]

Thanks for the fast reply tim and overdrive.

Overdrive, u said the best method is to have 3 router. Is this due to the dir655 lacking wds? I don't mind getting other router than dir655... I wanted to get it cause IT has good reviews. Anyway, by substituting this dir655 with any other good router that you recommend, can i eliminate the need for a third router? A third router would be a bit expensive for Me.

Yea, the N is mainly for copying files from a PC at C to the NAS at A. The distance bet. them is less than 15metres but has two concrete walls and a outdoor area in between.

Tim, you mentioned 2 APs. Is the idea also same as overdrive or is it different?

Thanks guys.

 

[overdrive31]

The DIR-655 doesn't support WDS, it did few years back, but chances are you won't find one. Cheapest route would probably be to use 2x ASUS RT-N13U(wireless N 2.4GHz) bridged from modem to gateway router. 3 routers total, but the 2 ASUS routers only cost ~$100 and a 3rd as the gateway another ~$50. I think Tim was suggesting to just set the 2 ASUS up as repeaters, you may lose half bandwidth for devices upstairs though.

 

[powerleakin]

Ok so two ddwrt routers to bridge the modem and the gateway(dir655)
say I want to maintain the n speed of the 655, can my g devices connect to the g routers to use the Internet? They don hv to be able to access PCs on the 11n network(can they?)

 

[thiggins]

Tim, you mentioned 2 APs. Is the idea also same as overdrive or is it different?

I'm suggesting a simpler and incremental approach using just two routers that support WDS, one configured as a router, the other as an AP.

 

[powerleakin]

Oh I see...will my bandwith be halved?

 

[overdrive31]

Tim is saying the ASUS routers support WDS within their built in firmware, they may as well support DD-WRT for increased functionality, but since they already support WDS don't worry about DD-WRT or the like. Modem>>WDS router>>WDS AP(repeater)>>wireless clients(some may even connect to the router as well), the router is the gateway and the AP is a HOP or repeat of the signal causing bandwidth to be half, but only for the wireless clients which must connect to the AP.

In Tim's setup you use less routers total but lose bandwidth using the repeater, but also allows clients near router to connect to it rather than all connecting to the repeater. >>Moderate setup difficulty<<

My setup the WDS routers are just a wireless bridge(only they talk to one another, so no wireless devices can connect), then the third router is the remote gateway serving up wireless N for all clients >>Low-Moderate setup difficulty<<, but you can also try having one of the WDS routers be a gateway the other being a WDS client and the third being a wireless AP all without any bandwidth loss. >>High setup difficulty<<

 

[thiggins]

Oh I see...will my bandwith be halved?

Only for wireless clients connecting to the remote AP.