Difference between 802.11b and 802.11g infra?

[c.ong]

Hi,

I have some questions regarding 802.11g and 802.11b infra.

Scenario A

The wireless LAN infra is 802.11g access point which supports up to 54Mbps bandwidth. There are 10 clients with 802.11g card. They are 10 metres away from the access point.

Scenario B

The wireless LAN infra is 802.11g access point which supports up to 54Mbps bandwidth. There are 10 wireless clients, 5 of them with 802.11b card and the rest with 802.11g card. They are 10 metres away from the access point.

I would like to know whether the existance of 802.11b client il scenario B will cause the infra to operate only 11Mbps instead of 54Mbps.

Will the 802.11g clients in scenario B experience drop in performance as compared to clients in scenario A.

Is there any supporting documents which I can refer to better understand the difference between 802.11b and 802.11g Infra? What is the drawback to have 802.11b clients in an 802.11g infra?

Thanks.

Delon

[gamccall]

Having b clients in your cell will not change the 54Mbps datarate for your g clients. However, datarate is not the same thing as throughput.

11Mbps 802.11b has an actual throughput of about 6Mbps. A g-only cell at 54Mbps has an actual throughput of about 22Mbps. However, putting b clients into a g cell decreases throughput even further for your g clients, to about 14 Mbps (if using 'CTS to self'; other anti-contention schemes are even worse). The reason for this decrease is that the b clients do not recognize the g clients as existing, so they will transmit even if a g client is already in a conversation.

Also, since your b clients communicate slower than your g clients, they'll tie up a disproportionate amount of the AP's bandwidth- they have to be online longer in order to transfer the same amount of data.

You're still better off with a g access point than with a b model, but it's not 5* as good as you'd think from the raw data rates.