What is it?
Directories have long been used to manage user identities and devices across networks. Now they are part of e-business infrastructures, managing access to resources within and outside the company.
The two leading commercial products are Novell's eDirectory - formerly Netware Directory Services (NDS) - and Microsoft's Active Directory, but there are other options.
The X.500 Directory Access Protocol, an ITU-TS standard, has been confined to government, defence and other organisations where security overrides ease of use. The Lightweight Directory Access Protocol (LDap) is a simpler, commercially viable implementation of X.500 for Internet use.
Where did it originate?
NDS was released with Netware 4 in 1993. Active Directory was first shipped with Windows 2000.
What is it for?
Microsoft describes Active Directory as a directory service for distributed computing environments. Similarly, Novell eDirectory "centralises the management of user identities, access privileges and other network resources".
What makes it special?
Microsoft says, "In addition to providing comprehensive directory services to a Windows environment, Active Directory is designed to be a consolidation point for isolating, migrating, centrally managing and reducing the number of directories that companies require."
However, Novell, with a more mature and stable product, has won the backing of some major analysts. A report by Gartner Group from June 2001 says, "Active Directory is a 1.0 release of a Microsoft technology, it is not as technically capable as NDS and will not be for at least four years.
"Heterogeneity will continue to be a Novell strength and a Microsoft weakness."
Microsoft counters that Active Directory has better security services, is a better platform for directory consolidation, and has the support of more infrastructure and applications suppliers.
Where is it used?
Novell claims that 90% of Fortune 500 companies use NDS/eDirectory, and there are more than 178 million user identities worldwide and hundreds of millions of applications and devices.
Estimates on how many Windows 2000 users are deploying Active Directory range from Microsoft's claim of 75% to Giga Information Group's February 2001 finding that less than 15% were using the product in any way, and that the majority had no immediate plans to implement it.
How difficult is it?
Basic training in eDirectory or Active Directory will take experienced Netware or NT/Windows 2000 professionals five days.
What does it run on?
As well as Windows NT and Windows 2000, Active Directory also supports Netware 5, as a way of providing Novell users with a migration path. Novell claims eDirectory supports Netware, Windows NT/2000, Solaris, Linux, Compaq's Tru64 Unix and IBM AIX.
LDap is supported by Novell, Sun/iPlanet, IBM, Oracle, Critical Path, SAP and BEA among others, but only to a limited degree by Active Directory, through the proprietary Active Directory Services Interface (ADSI).
What's coming up?
The Directory Interoperability Forum, part of the Open Group, is working on standards to enable directories to interoperate freely, regardless of supplier.
For details of Microsoft's certified training partners see www.microsoft.com/uk/skills. To find your nearest Novell certified training centre go to syndication.solutioncentral.com/syndsearch.asp?iSyndid=66.
LDap training is offered by companies that support it, and there are plenty of Web-based resources, some free, that can be found through any search engine.
Rates of pay
Active Directory support roles command about £25,000, while those working in design and implementation can expect between £35,000 and £40,000. Novell skills tend to be better rewarded than Microsoft.