The proliferation of wireless handheld devices, such as laptops, PDAs, iPhones, and more, puts increased strain on today's wireless networks. As the technology continues to evolve rapidly, network engineers are in a race to keep up-both with system interoperability concerns, and throughput, reliability, and security issues. Now more than ever, you need a solid understanding of wireless network concepts and technologies so that you can choose the right tools for securing your network and optimizing performance. The security of the new WLANs and their performance depend on active, informed network management. This white paper explains the architecture, topologies, and security issues of wireless networks.