Can directories keep NOSes in sync?
- By Jason z_rne
- Mar 08, 1999
A still-immature network operating system, NT Server does not have a directory
structure and cannot scale up to enterprise levels as well as other NOSes can. Nor has
Microsoft Corp. developed good ways of making NT work with other NOSes.
But the competition has. Novell Inc. has delivered a second version of Novell Directory
Services for NTessentially acting twice as an organ donor.
NDS, the network directory for Novells NetWare NOS, lets NetWare administrators
bring servers running NT into the NDS fold and manage them. Applications running under NT
Server also can take advantage of the NDS directory structure.
The long-delayed release of Microsoft Windows 2000 Server and its Active Directory will
complicate the NOS interoperability picture because SunSoft Solaris, IBM AIX and
Hewlett-Packard HP-UX are not going away.
The NOS vendors would like to see network managers give up and migrate everything to
their individual operating systems, but managers are notoriously reluctant to abandon
existing investments. That leaves them with the headache of getting a mixture of
utilities, applications and third-party products to play nicely with network siblings.
Some NOSes do coexist better than others. Novell, the double organ donor for NT, also
has brought out an NDS version for Solaris. The second release of NDS for NT no longer
even requires a NetWare server to be present on the network.
Sun Microsystems Inc. also has created many tools to ease file transfers between its
Unix OS and Microsoft Windows systems. Soon it will release software code-named Project
Cascade [GCN, Feb. 22, Page 32] that will run NT
Primary Domain Controller services natively under versions of Solaris.
What does all this mean for the government administrator searching for ways to link
directories or network services?
First, before starting such projects, get your house in order. Audit the current
Examine directory objects or domain structures to make sure they are up to date and
exhibit no problems. Any little glitch is likely to be exacerbated by migration or
Second, make sure you are running the appropriate client software. For example,
installing NDS for NT 2.0 is difficult with the latest NetWare client software for NetWare
Older versions do work, but the IPX protocol must be running for the client to see
NetWare on the servers.
In normal use, a Windows client need not have an installed NetWare client to work with
an NT server running NDS for NT 2.0. And small or remote NT networks can get directory
replication and NDS functions without having to set up a local NetWare server.The best
integrations are transparent to users. Suns Cascade promises to make NT
authentication services available on the Solaris platform, identical to those provided by
a standard NT platform. Windows NT Server 4.0 networks can replace a number of NT Primary
Domain Controllers with a single, more scalable Solaris platform running Cascade software.
This is an important advantage of NOS integration over migration. Well-integrated
multiple operating systems deliver the best of each plus ways to avoid the worst of any
particular one. Integration also makes it possible to manage different file formats on
networks with Unix servers or clients and to sign on and change passwords more easily.
The bogeyman of integration is directory synchronization. One approach keeps the
different directories in sync through a middleware application. Directory objects from one
NOS may not be translatable to the directory structure of another, however, and problems
can crop up on both sides.
A second approach is the metadirectory. Instead of synchronizing two directories with
each other, you synchronize them with a third directory that supports the features of
both. Conflicts are easier to manage, and all the information is contained in one store.
But this approach also has potential problems. It is more difficult to execute
successfully, may make management harder rather than easier, and causes more network
traffic. Because it essentially stores the same information twice, it raises the hardware
requirementsa vital consideration if there are thousands of directory objects.
The arrival of Microsofts Active Directory and Windows 2000 will make network
integration still murkier.
Sun, for example, licensed the Windows NT source code from AT&T Corp. for use in
Project Cascade, but it cannot do the same thing for Windows 2000 code because of a recent
lawsuit between AT&T and Microsoft. Other vendors such as Cisco Systems Inc. of San
Jose, Calif., could license the new source code to Sun, however. Sites that install the
Project Cascade software this year with Windows NT Server 4.0 might not be able to upgrade
when Windows 2000 finally arrives. And there is no clear signal as to how well NDS for NT
will support Active Directory, or what integration tools Microsoft will provide. Microsoft
has announced migration tools for Win 2000 from NetWare, but many government offices could
not afford such a migration in any case.
Even rolling out Windows 2000 and Active Directory into an all-Windows network will
take some planning. Not enough information exists as to how well a staged deployment of
Windows 2000 Server would interact with existing Windows NT Server 4.0 installations.
Third-party metadirectories and synchronization tools are yet another hurdle in
upgrading an existing operating system. Incompatibilities could damage directories and
cause system crashes, performance degradation or just poor resource reporting.
The bottom line: Government sites probably should either run Active Directory alongside
NDS to get the advantages of both or run NDS for NT and ignore Active Directory until it
matures. NDS is the better choice because it works across more platformsNT, Solaris,
and NetWareand represents the largest potential compatibility base. Until Active
Directory develops beyond the Windows platform, it is not a good choice for enterprise
Directory integration lies at the heart of making any two NOSes get along. How well do
the directories integrate? How transparent is the result? How easy is it to manage?
The good news is that lots of attention will be focused on these three questions in the
next couple of years. Agencies will soon have a greater choice of NOSes without giving up
their present systems. Integration can be done today, but it will be easier later.