System Roaming

When dealing with open systems and frequency specifications, we must
note that roaming plays an important role in identifying basic message
format types. One of the elements necessary to support those areas of
WLANs not covered by network vendors involves the interaccess point
protocol (IAPP). IAPP enhances the interoperability of roaming wireless
devices, regardless of manufacturer. IAPP addresses roaming that uses
either a single extended service set (ESS) or roaming that occurs between
two ESS units.

The problem with system roam is that it is far too easy for any computer
in a Windows, Macintosh, or Linux environment to roam onto an
802.11 network. The hardware from each network vendor was designed
for interoperability, so it is a simple matter for anyone on virtually any
platform to roam easily (using an open system of authentication) and
see all your network resources, intranet, file shares, and even access all
of your network printers. The concept of system roaming is to be able to
limit and define which users have access and what resources they can
view. If you leave your wireless system completely open, it becomes a
vulnerable target that anyone can exploit. Such vulnerabilities, using
freely available spectrum communications, can leave your network open
to attack and make it easy for someone to view, steal, modify, or even
corrupt mission-critical data.