Make sure that interoperability and adherence to standards is high on the list of priorities when judging software. If interoperability is of sufficient quality then you should be able to select from a range of products. This means, for example, that you?ll have the freedom to purchase server and client software from different vendors. Similarly you will be able to choose products that match available platforms, which will be useful if your organization is a mixed hardware environment. Most vendors submit their software to interoperability tests and you should ask for the results of these. Software developers should also have a commitment to future standards and advances in technology. It won't help if the current product is conformant to prevailing standards, but future offerings diverge from the straight and narrow. Ask for demonstrations that show how well the product performs with large databases. The ability to run a search quickly through a large number of entries is important, as is the speed at which directory updates are processed. Request performance figures from tests using databases at least as big as your own will be.
Interoperability is again important. The freedom to mix and match is fundamental. As well as allowing you to select different products to match different needs, it means that other organizations can access your directory using their software. Interoperability improves accessibility. Desktop integration is vitally important. User interfaces will ideally work with the applications staff are using now, e.g. word processors, calendar/diary managers and e-mail interfaces. Clients that employ non-proprietary methods of integration are advisable as these will co-operate more easily with standard software. It may be appropriate to look at clients specific to a application. E-mail interfaces in particular may have an associated directory component that is capable of accessing your service. Latest versions of the popular communication suites from Netscape, Lotus and Microsoft are examples.
Begin by estimating levels of usage, using this to determine the hardware requirement. It is probably better to overestimate somewhat in order to allow for future growth. Other factors are the level of resilience required and the overall size of the database. If resilience is an issue then backup machines may be needed. It may be possible to combine a directory service with other services on the same machine, but the demands of each service must be considered if service is to be maintained.