Why more than 2 powerline adapters ?

[hw_user]

I have used a powerline adapter starter kit which comes with 2 units. But I can actually purchase a single unit. Buy why do people need the single unit ? I think they also works in pairs.

 

[Flying Head]

To have 3 or 5 devices.

 

[bill001g]

They form a network between all the devices in effect forming a large switch. The limit to the number of devices is fairly small 6 if I remember correctly. The very quickly degrade performance when you go above 2 devices. Still it is better than running 2 different pairs of devices that do not communicate. When you do that the 2 networks interfere with each other when both are used in the same house.

 

[KushDragon]

You just need one primary powerline adapter to send a signal through your grid. After that you can have several "access point" powerline adapters that source signal from the primary.

 

[hw_user]

This is a follow up question to the answers provided
Does it mean that the primary adapter acts like a hub. For example if I have 4 adapters, with the primary connected to the router , I can have the others connected to 3 PCs sharing the single connection to the router.
If I have 4 adapters and only need to connect 2 PCs to my router, I can 2 options
1. have 1 primary adapter and 2 'access points' for the 2 PCs (i.e. only use 3 adapter units) or
2. have 2 primary adapters and 2 'access points for the 2 PCs (i.e. using all 4 adapters).
In case of option 1, the 2 PCs are sharing a single connection to the routers which means half the bandwidth for each PC. In the case of option 2 , each PC will have its own connection to the router.
Are these 2 options valid ? From the surface, is option 2 a better option ?

 

[bill001g]

It does not technically act as a just a hub, When you have 3 units the 2 remote units also form a connection directly between each other. There is some overhead wasted in doing this even if you never transfer data between the 2 end devices.

In option 2 you are looking at it incorrectly. Yes they must share a physical port on the router but the router port is likely 1gbit which is much faster than any powerline connection. So if you connect 2 powerline units to the router you could say you get 2gbit BUT the actual connection must share the wires inside your house. The connection appear as if each pc has a connection to the router but now you the 2 pair of powerline networks devices sending data over the top of each interfering. This is much worse than when they act as single group. When they act as a single group they talk to each other and try to prevent interference when they run as 2 pair they just stomp all over each other. Now if you were to run them as a single group you still can not hook 2 to the router you will get a loop and crash your network.

Pretty much the optimum way is to use 3 powerilne units. The bottleneck is not the port in the router it is the electrical wiring in the house. You will be lucky to get 300mbits/sec even out of the very best powerline units.