Troubleshooting Connection Problems in Wireless LANs
You could face connection problems when moving from one access point’s area to another’s. This happens when the two access points have different subnet masks. WLANs that work on the older 802.11a (5 GHz frequency) system are not compatible with newer standards such as 802.11b and g.
The newer versions work on the 2.4 GHz frequency and are backward compatible. You will have to upgrade your network card if you want to connect to an 802.11b/g network.