This brief chapter collects together the loose ends left over after the substantial chapters describing the security protocol. We started by reviewing the process by which mobile devices join to an access point. We then explained the use of the WPA/RSN Information Element that is employed in the negotiation of security capabilities between the mobile device and the access point.
After considering the process for joining a network, we looked at the issue of roaming from one access point to another. A problem is created if a full authentication handshake is needed every time such a roam occurs because the authentication exchange could take a second or even more. At the time of writing, there are a number of proposals for "fast roaming" using preauthentication or cached keys. We looked at one example of a preauthentication scheme.
Finally we returned to the difficult issue of security in IBSS (ad-hoc) networks. In this case the lack of a central coordinating device such as the access point creates a problem. We reviewed the approach for IBSS security as defined for IEEE 802.11i.