deoends on the quality of the router on the network, if you have a decent one it wont do anything becous if you have a decent dhcp server it gives them both a different ip and that will then be used for keeping them sperate, let me explain, mac1 and mac2 are clones, but mac 1 ask for a ip and the dhcp server gives one, mac 2 then ask for a ip and the dhcp server gives a ip to that mac adress, but mac1 ignores it becous he already has one, and mac2 takes it, and after that they are both different clients but with the same mac, problem is if you have a older type of router, those could give errors but newer types like >2005 are all capable of working with the same mac adresses, next to that, the mac 11:22:33:44:55 is a spoofed mac, becous the device that has this mac is not even a wireless device, so my guess is that someone is hacking your netwrk, for more info google aircrack-ng or hacking wifi with backtrack.

deoends on the quality of the router on the network, if you have a decent one it wont do anything becous if you have a decent dhcp server it gives them both a different ip and that will then be used for keeping them sperate, let me explain, mac1 and mac2 are clones, but mac 1 ask for a ip and the dhcp server gives one, mac 2 then ask for a ip and the dhcp server gives a ip to that mac adress, but mac1 ignores it becous he already has one, and mac2 takes it, and after that they are both different clients but with the same mac, problem is if you have a older type of router, those could give errors but newer types like >2005 are all capable of working with the same mac adresses, next to that, the mac 11:22:33:44:55 is a spoofed mac, becous the device that has this mac is not even a wireless device, so my guess is that someone is hacking your netwrk, for more info google aircrack-ng or hacking wifi with backtrack.