Sharing Network Speed Among Clients

[Bulldog]

I have a basic misunderstanding about how devices on a wireless network share the network's data transmission speed.

I have an all-802.11n network which currently operates with a top speed of 270 Mbps. Does this mean that each n client on the WLAN can communicate with the router at 270 Mbps? Or is the 270 Mbps shared among all n clients on the network, so that if two or more devices are active on the network at the same time, the top speed of each will be some fraction of 270Mbps?

To make things even more complicated: What would happen if I add an 802.11g client to the network (say a printer or a Roku.) Does the g client operate at 'g speed' while the n clients operate at 'n speed'? Or does the entire network now operate at 'g speed' -- even if the g client is powered off?

As you can imagine, I also don't understand the difference between '802.11n mode' and 'mixed 802.11n and 802.11g mode' in my router's configuration settings.

If this is too big of a topic for a forum post, I'll be grateful for some prods in the right direction.

Thanks for your help.

 

[thiggins]

The "top speed" of 270 Mbps is actually PHY or link rate. Actual application-level speed is under 100 Mbps best case.

All devices connected to the same access point share the bandwidth. If you had two clients running full blast under best-case signal conditions and (for simplicity sake) 100 Mbps of available bandwidth, each would use roughly 50 Mbps.

When you run a mix of draft 11n and 11g clients connected to the same AP, they again share the bandwidth. But since 11g clients operate at a slower speed, the effect is more complicated.

The effect differs from product to product, but basically, when 11g clients are active, all clients must slow to 11g speed. This effect happens only when 11g clients are actually transmitting. If they are associated, but idle, draft 11n clients operate normally.

An example of this behavior can be seen in the NETGEAR WNR2000 review.

 

[Bulldog]

Thank you for the information and the link.