Wireless LAN

Aggressor Prime · Post by **Aggressor Prime** » Tue Jun 28, 2005 12:03 pm

I am moving into a new house that cannot support a wired LAN but that works very well with a wireless LAN. I need ideas on a router that can support 6 computers, is fast (~100Mbps), and has the best security. I also want it to come from a good company like Linksys. I also need PCI cards that can support the router.

Mobius · Post by **Mobius** » Tue Jun 28, 2005 2:26 pm

Currently 54Mb/s is the fastest wireless standard: 802.11g

Some routers have "full duplex", so combined upload and download is 108Mb/s - but let me be suggest to you, if you get 20Mb/s both ways on a sustained transfer, then that is pretty good. Wi-Fi can be pretty lossy.

Another thing to consider is that a WAP has a *total* of 108 Mb/s - and if 6 PCs are connected, trying to transfer files, then that total amount of bandwidth is *shared*. i.e. 15+/- Mb/s for each machine.

CDN_Merlin · Post by **CDN_Merlin** » Tue Jun 28, 2005 7:58 pm

My Linksys wireless router has 4 ports on it. You'd need to connect another router or a switch to the port and have 2 of them on the switch.

No, why can't it support wired? It's just laying the cable down. Don't need to staple anything or make any holes.

BUBBALOU · Post by **BUBBALOU** » Tue Jun 28, 2005 8:09 pm

A house that can not be wired??? Never heard of such a thing!

Are you renting the house or is it made of glass?

(BTW I used install Networks CAT6/CAT5E/CAT3/Fiber/IROB/CSU-DSU/T1 150-400 drops per premise)

SuperSheep · Post by **SuperSheep** » Wed Jun 29, 2005 7:33 am

http://www.linksys.com/products/product ... 5&prid=601

I got this one and I like it.

Canuck · Post by **Canuck** » Wed Jun 29, 2005 11:09 am

I hung one of those off a port on my wired router, turned off DHCP and used it to provide wired ports in another area of the house. And of course the wireless.

Works great.

Admiral LSD · Post by **Admiral LSD** » Fri Jul 01, 2005 12:19 am

My first guess would be that he's renting but at the same time I know from experience that some places can be more difficult to run cable in than others. With ducted AC and limited roof space, running cable in my place was an absolute ★■◆●. He may just want to avoid the trouble. Had 802.11 wireless been available back when we did my place I can't honestly say I wouldn't have given serious thought...

Also, Mobius' math is slightly flawed. "Full-duplex" simply means it can be transmitted in both directions at the same time. It doesn't magically double the overall potential bandwidth. Even under full-duplex the link speed would still be limited to 54Mb/s so with 6PCs, the effective bandwidth would be 9Mb/s in each direction and not 15. If they were to add another 54Mb/s channel that would increase the max bandwidth to 108Mb/s but that isn't full-duplex but something else, channel bonding or something I think.

Plebeian · Post by **Plebeian** » Fri Jul 01, 2005 7:15 am

Admiral LSD wrote:Also, Mobius' math is slightly flawed. "Full-duplex" simply means it can be transmitted in both directions at the same time. It doesn't magically double the overall potential bandwidth.

I think that it sort of does, but only in "marketing" terms. Unless, that is, if you're sending data at 50Mbps on a 100Mbps link then you can only receive at 50Mbps, but I think that's how half-duplex works.

You won't get 200Mbps download speeds, but you can have a total of 200Mb of data moving through the link at once (100Mb in and 100Mb out). I think, anyway. Otherwise, what benefit does full-duplex have over half-duplex?

Admiral LSD · Post by **Admiral LSD** » Fri Jul 01, 2005 10:17 am

Afaik, ethernet is 10/100/1000/10000/whatever irrespective of whether the link is half- or full-duplex. Half-duplex simply means that it can only either transmit or receive at any given time. In order to receive it has to cease transmitting and vice versa. This bouncing around between transmitting and receiving does result in an overall reduction in throughput but the instantaneous transmission rate remains the same. Full-duplex doesn't really give you any more bandwidth, it just allows you to utilise your existing bandwidth more efficiently.

Plebeian · Post by **Plebeian** » Fri Jul 01, 2005 11:09 am

I think we're probably saying the same thing here.

Take this example: Say you're on your local network, and happen to be able to fully-utilize the network (impossible, I know, but let's pretend). You're copying a 100MB file to your machine, and copying a 10MB file from your machine.

With a half-duplex connection, the time taken should be for your 10/100/1000/whatever connect to transfer the 110MB total. With full-duplex, shouldn't it be the time to transfer the 100MB since that's the largest one-way transfer and the 10MB file should be getting transferred at the same time? (Less of course the additional ACKs and such since those have to use the same "side of the cable" as it were.)

It doesn't mean you have bandwidth of 20/200/2000, but you have concurrent X up and X down, so you could move 2X per second, but only when you're fully utilizing the upload and download. If you're just doing one, then you can only get your "rated" speed.

At least, if I'm thinking about it in the right way. It'd be like a two-way road with one lane in each direction, instead of half-duplex's one-lane road (where cars will be allowed across in one direction at a time, to prevent collisions). So with this full-duplex road, you can have cars going both directions, and while the road can handle X cars going a given direction because of its length, there can be 2X cars on the road in total. But just because the road can have that 2X on it when it's busy, it doesn't mean that during rush hours you can get 2X people going in a single direction (people can't drive down the wrong side of the road).

So with this whole car thing, it'd be like a road being able to support 100 cars going by a minute. The full capacity of the road is 200 cars per minute (100 each way), so the city could claim that as a maximum throughput figure and be correct, but it's also correct to call it a 100 car-per-minute road, since that's what each side can handle, and it'll let you know how many cars can be handled during rush hour (since most people will be going one way), but it doesn't prevent people from trickling by going in the other direction.

BUBBALOU · Post by **BUBBALOU** » Fri Jul 01, 2005 7:26 pm

Half Duplex = 100Mbps transmit or receive (100Mbps throughput)
Example of Half Duplex = Walkie Talkie

Full Duplex = 100Mbps transmit and receive (200Mbps throughput)
Example of Full Duplex = Telephone

Full Duplex only works between 2 nodes, must be a switch not a hub(multiple nodes) both must have full duplex enabled and if a switch is used, it must also be full duplex at the same rate.

The only difference between the 2 is when both nodes are transfering data to each other, Full Duplex does not have to wait for the data packet to finish from the other node to transmit

Well look at that... I didn't even break a sweat. My examples are the way it works folks!!!