Vendors in the wireless LAN "overlay" category - those that sell products used in conjunction with RF access points and network interface cards built by other vendors - are taking measures to ensure their survival.And they are raising a key question for you to consider: Do you want to get your ancillary WLAN services - configuration and site-survey tools, authentication, monitoring, rogue AP detection - from your primary AP\/NIC vendor or from a third party that is vendor-agnostic? There is considerable feature overlap among the offerings of the various suppliers. Sorting out how to get those features you need while considering how many vendors you are willing to have in your network is a primary challenge.Overlay vendors can add complexity to your network; on the other hand, those with open architectures can drive innovation and are beneficial for service consistency in wireless networks comprising multiple AP\/NIC vendors.Consider ReefEdge, which has long offered a security and management appliance to be used in conjunction with WLAN infrastructures.\u00a0 At Networld+Interop 2003 last week, the company announced a framework for service interoperability it calls the Wireless Services Fabric. According to ReefEdge CTO Sandeep Singhal, the architecture follows a Web services model, with common data stores and messaging interfaces, to enable services developed by ReefEdge and third parties alike to communicate with one another to deliver a consistent view of users, policies, traffic, and so forth.The framework, at this juncture, is "quasi-open," in that ReefEdge is being selective about the partners that develop services for it (rather than just putting it in the public domain).At announcement, the framework included a module from Wavelink, the Wavelink Mobile Manager for RF configuration, which is the first outside service to be integrated into the fabric. Meanwhile, ReefEdge announced three products of its own that fit the framework:*AirMonitor, an AP-like device that mounts in the ceiling to detect access point failures and unauthorized changes to the WLAN configuration.*Multi-Site Manager, for centralized, data center-based configuration and management of up to 2,000 sites.*The CS200 Wireless Network Concentrator, which bundles the various services in software within a single device, rather than requiring you to purchase multiple dedicated appliances to get the services.