ch09.htm

this describes managing multivendor networks

potential of creating overly complex or difficult-to-use names for network resources.
In a very real sense, NDS has become Novell's key competitive advantage in the PC
LAN market.


<BLOCKQUOTE>
	<P>
<HR>
<FONT COLOR="#000077"><B>Integrating NDS</B></FONT><BR>
	Rather than limiting NDS to a NetWare-only environment, Novell is extending NDS to
	other environments. For example, Novell is working with HP to join DCE software with
	NDS in a future 64-bit UNIX release. Novell is also collaborating with SCO so that
	it can merge NDS with the 32-bit SCO UNIX systems. Similar plans are underway for
	integrating NDS with other vendor operating systems, as well as for releasing NDS
	client software for a variety of desktop operating systems. 
<HR>


</BLOCKQUOTE>

<P>Finally, Novell is also improving NetWare's position in large enterprise environments.
In large environments, NetWare worked well as file and print servers, but did not
fare well as database or messaging servers. To address this limitation, Novell has
introduced <I>NetWare Symmetrical Multi-Processing (SMP) 4.1,</I> which enables NetWare
to take advantage of multiple processor hardware platforms. Under this release, an
SMP NLM replaces the NetWare OS kernel that comes with 4.x. SMP's multiprocessor
performance is comparable to that of NT, and scales well with additional CPUs. NetWare
4.1 SMP is currently available only from server hardware vendors, but Novell is also
planning to introduce a shrink-wrapped version.
<H3><A NAME="Heading2"></A><FONT COLOR="#000077">Basic Architecture</FONT></H3>
<P>The server aspect of NetWare was designed to operate in a dedicated, Intel-based
system. Although NetWare has been ported to non-Intel systems where it can run alongside
other applications, the majority of NetWare installations are, in fact, dedicated,
Intel-based servers. In this environment, the core NetWare system is launched from
DOS--you boot up the server under DOS and then run NetWare. At that point, NetWare
takes over the system and DOS is no longer the dominate operating system.</P>
<P>The configuration and management of a NetWare system can be performed at the system
console, which is the keyboard and the monitor attached to the system. The system
console provides a simple, character-mode interface for configuration and administration
tasks. Alternatively, NetWare contains a remote console utility that enables you
to perform most console functions from a client workstation. In contrast, the configuration
and management of the NetWare user environment is typically performed from a client
workstation using an administration tool.</P>
<P>Originally, NetWare used server-based security that required each user to log
on to every server on which he or she needed resources. With the advent of NDS, however,
user permissions can be set up on a network-wide basis, and each user simply has
to log on to the network once. After a user logs on, NetWare can activate a user-specific
batch program (a log on script) that allocates the resources the user accesses on
a regular basis. For example, the log on script can mount NetWare directories as
network disk drives so the user can access specific applications or business data.</P>
<P>The configuration of the client-side software that handles the communication between
the client system and the NetWare server(s) has changed dramatically as NetWare has
evolved. For NetWare releases prior to 3.12, the client-side software that handles
traffic to/from the network adapter has to be &quot;generated&quot; using the NetWare
utility WSGEN.</P>
<P>WSGEN is an interactive program that combines software that handles the physical
network adapter in a client PC with software that implements the NetWare IPX protocol.
WSGEN outputs a program file called IPX.COM that must be loaded in each PC prior
to accessing the NetWare network. You need a version of IPX.COM for every unique
type of network adapter in your PC network, and you must make sure each version of
IPX.COM pairs with the network adapter it was generated to use.</P>
<P>In a pure NetWare environment, you load IPX.COM in the AUTOEXEC.BAT file. Because
IPX.COM handles all the network adapter functions, NetWare requires no CONFIG.SYS
device drivers. After IPX.COM loads, a second NetWare program, NETX.COM, is launched
to integrate the NetWare functions into the DOS environment. After NETX.COM loads,
you can log on to a NetWare server and start accessing NetWare services (for example,
drivers, printers, NetWare Loadable Modules).</P>
<P>By most standards, interactively generating an executable file (in other words,
IPX.COM) to handle each type of LAN adapter is less than ideal, especially if you
have more than one type of adapter in your network. For example, if you're installing
a workstation in a remote department and you bring the wrong IPX.COM file, you're
basically out of luck. You also have an issue of version control--if you generate
multiple IPX.COM files, you have to figure out how to identify which file applies
to which adapter.</P>
<P>Given the awkward nature of WSGEN, network vendors looked at the problem of marrying
proprietary protocols to a wide range of network adapters and tried to find a better
approach. One of the key outcomes of this investigation came in 1988 when IBM, Microsoft,
and 3Com introduced the <I>Network Driver Interface Specification (NDIS)</I> as part
of the OS/2 LAN Server. NDIS addresses the problem of marrying adapter boards to
protocols by dividing the functions into two logical layers:

<UL>
	<LI><I>Adapter interface layer.</I> Manages and communicates with the physical adapter.
	The adapter interface presents a &quot;generic&quot; interface to the network interface
	layer (described below), so every adapter essentially looks the same.<BR>
	<BR>
	
	<LI><I>Network interface layer.</I> Implements the desired network protocols (for
	example, NetBIOS/NetBEUI or TCP/IP) and communicates with the physical adapter via
	the &quot;generic&quot; interface the adapter interface layer provides.
</UL>

<P>Novell was not blind to NDIS's development. But instead of embracing NDIS, Novell
created its own solution--the <I>Open Data-link Interface (ODI).</I> Like NDIS, ODI
separates the physical network adapter's functions from those of the network protocol.
Despite the apparent similarities, however, ODI is not compatible with NDIS (although
NetWare does include an ODI &quot;shim&quot; module--<I>ODINSUP</I>--that enables
NDIS and ODI traffic to coexist on the same physical adapter).</P>
<P>Novell's ODI standard requires certain files and programs to integrate network
protocols with a wide variety of network adapters. Unlike Microsoft's Network Driver
Interface Specification (NDIS), ODI does not require any device drivers in the CONFIG.SYS
file. Instead, ODI operates from a batch file (normally the AUTOEXEC.BAT startup
file) or directly from a command prompt. The ODI programs include:

<UL>
	<LI><I>LSL.COM.</I> The <I>Link Support Layer (LSL)</I> program is NetWare's ODI
	baseline program. It interfaces with vendor-supplied adapter programs and provides
	a consistent interface to the higher-level ODI modules.<BR>
	<BR>
	
	<LI><I>XXXXXXXX.COM.</I> Each network adapter manufacturer provides a software driver
	that operates with the LSL program. For example, the SMC8000.COM program provides
	an interface to the Western Digital and SMC line of Ethernet Plus adapters.
</UL>

<P>Specific programs are then layered on top of the previous two files to implement
network-specific features and functions. These files are:

<UL>
	<LI><I>IPXODI.COM.</I> This program implements NetWare's core IPX protocol suite
	over the underlying ODI drivers. It is analogous to the IPX.COM program used in pre-ODI
	environments.<BR>
	<BR>
	
	<LI><I>VLM.EXE.</I> The <I>Virtual Load Module (VLM)</I> program starts specific
	NetWare work- station services based on the configuration file (described in the
	following paragraph). This program is the analogous to the NETX.COM program used
	in pre-ODI environments.
</UL>

<P>All the programs obtain configuration information from the NET.CFG file, a text
file that defines the hardware's operational characteristics (for example, IRQ setting,
port value, and DMA address), the operating parameters for the various ODI programs,
and the interrelationships between the programs.</P>
<P>NetWare also includes client software for other, non-PC clients. Although the
implementation details for these other environments are obviously different then
for a PC environment, they all accomplish the same net result--a connection to a
NetWare server.
<H3><A NAME="Heading3"></A><FONT COLOR="#000077">Network Support</FONT></H3>
<P>As previously noted, NetWare typically relies on the Internet Packet Exchange
(IPX) protocol as the network transport between the client and server systems. Although
Novell is aggressively moving toward supporting TCP/IP instead of IPX, the majority
of NetWare installations still use IPX as the primary transport.</P>
<P>In reality, IPX is not really a single protocol, but actually a suite of protocols
(much like TCP/IP). IPX can carry a number of service protocols, including the <I>Sequenced
Packet eXchange (SPX)</I> protocol. By itself, IPX is a connectionless protocol that
does not guarantee delivery of messages. SPX, on the other hand, is a connection-oriented
protocol that runs as an extension to IPX and provides confirmation (or denial) of
the end-to-end delivery of messages.</P>
<P>NetWare service protocols can run under just IPX, or the IPX/SPX combination.
These services include:

<UL>
	<LI><I>NetWare Core Protocol (NCP).</I> This protocol handles the mainstream NetWare
	services, including accessing files and printers on NetWare servers.<BR>
	<BR>
	
	<LI><I>Burst Mode Protocol.</I> This is a variation of the NetWare Core Protocol.
	Designed for high-volume applications, Burst Mode enables a client to request and
	receive more data in a single message than under NCP.<BR>
	<BR>
	
	<LI><I>Service Advertising Protocol (SAP).</I> File, print, communication, and other
	types of servers announce themselves at regular intervals using this protocol. Client
	PC's &quot;listen&quot; for this protocol to determine what resources are available
	within the network. Clients can also use this protocol to inquire about the capabilities
	of specific servers.<BR>
	<BR>
	
	<LI><I>Routing Information Protocol (RIP).</I> This protocol is used to help a message
	move from one NetWare network to a second NetWare network. Routing protocols like
	RIP is an important factor in how wide-area networks are constructed.
</UL>

<P>The IPX protocol suite is clearly one of the factors contributing to NetWare's
success because IPX has a number of advantages over the two other protocol suites
commonly used in PC LANs (in other words, NetBIOS/NetBEUI and TCP/IP). These advantages
include:

<UL>
	<LI>Unlike TCP/IP, IPX does not require an extensive addressing scheme for clients
	and servers. IPX, like NetBIOS/NetBEUI, relies on the hardware addresses burned into
	network adapters.<BR>
	<BR>
	
	<LI>Although IPX does not implement its own system-level addressing scheme, it is
	a fully routable protocol (that is, it supports network address assignments). Because
	IPX is fully routable, you can interconnect multiple NetWare LANs in a relatively
	simple fashion. In contrast, TCP/IP is also fully routable but NetBIOS/NetBEUI is
	not.<BR>
	<BR>
	
	<LI>IPX is a relatively efficient protocol because it does not rely on client-initiated
	broadcast messages to establish client/server connections (as is the case in NetBIOS/NetBEUI)
	and it uses bit-based flags in its headers (unlike TCP/IP, which uses byte-based
	flags).
</UL>

<H2><A NAME="Heading4"></A><FONT COLOR="#000077">Microsoft Windows NT Server</FONT></H2>
<P>Windows NT Server is the result of the successes and failures Microsoft has experienced
with its earlier products and projects. Windows NT Server was clearly affected by
the success of LAN Manager and Windows for Workgroups, as well as the failure of
Microsoft's involvement with OS/2. If nothing else, Windows NT Server (and Windows
NT Workstation) is a genuine commercial-class operating system--Microsoft's first
entry into the marketplace of enterprise-oriented data processing.</P>
<P>Windows NT Server has not always been the darling of the industry. In fact, the
early releases of the product weren't exactly welcomed with enthusiasm. The first
change that steered Windows NT towards its current success came with the 3.51 release
of Windows NT--a release that introduced support for native Microsoft file and print
services over TCP/IP, IPX, and NetBEUI. This seemingly subtle change in networking
support enabled Windows NT to be easily deployed in existing networks.</P>
<P>Although version 3.51 enabled Windows NT to enter into new corporations and gain
new respect and appreciation in the industry, that change was nothing in comparison
to the changes that occurred in version 4.0 of Windows NT. Version 4.0 featured the
same user interface as Windows 95, which positioned Microsoft as a provider of a
complete client/server solution with a consistent, easy-to-use and easy-to-manage
user interface and user environment.</P>
<P>Of course, version 4.0 also contained significant improvements over 3.51. For
example, all of the NetWare coexistence/migration tools (further discussed in the
&quot;NetWare/Windows NT Server Integration&quot; section at the end of this chapter)
were included on the distribution CD (they had previously been sold separately).
Windows NT Server 4.0 also featured better TCP/IP integration, including the capability
to operate as a DNS server and as a Web server (via the Internet Information Server
included on the distribution CD). Support for TCP/IP integration is proving to be
a critical component for Windows NT.


<BLOCKQUOTE>
	<P>
<HR>
<FONT COLOR="#000077"><B>Window NT 5.0 and the Internet</B></FONT><BR>