Determining which service discovery protocols to support is a difficult decision that consumes both time and money. However, it is a decision that must be taken seriously, Incorrect decisions regarding service discovery can lessen your chances for success in your target market as well as impair your ability to enter other markets. Several business and technical aspects of service discovery protocols must be considered as part of this decision process.

The openness of the service discovery technology should be measured.  Ask yourself, who owns the service discovery technology? Are prerequisites needed that are outside your intended usage model? Is the technology proprietary or limited to a single platform? Can the technology be extended to other environments?

Consider the cost of implementation. Use of some service discovery technologies requires payment of royalties and licensing fees, which can result in significant direct costs. Other costs associated with service discovery protocols include SDK fees, cost of development tools, and expenses for compliance testing.

Does the technology provide more than basic service discovery function? For example, can the protocol determine if the service is available, and can the technology bind to it, setting up an interoperable session? Can the technology locate and load needed device drivers?

Also, determine if the client or the service is responsible for comparing service requests with services provided. Client-side comparisons can be more costly, with the function being delegated to each application or service above the API.

To assure the broadest market penetration and fewest portability issues, consider technologies that are independent of operating system environment and communication protocol, and technologies that target multiple platforms. Bandwidth limitations should also be considered. How much data traffic is required to provide the basic discovery function? Is this amount consistent with your bandwidth requirements?

Directory centric network models are prevalent in enterprise and small business applications. Efforts are underway to extend this model to public networks such as the Internet and extranets. However, mobile technologies have given rise to ad hoc, peer-to-peer networking. In this model, a central directory is not necessary. Devices and services negotiate one-on-one with each other, advertising their own capabilities and finding devices or services that meet the needs they require. Therefore, when selecting a service discovery protocol, look for one that will function equally well in both directory based and ad hoc network situations.