Guide to Networking Essentials

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Guide to Networking Essentials

Fifth Edition

Chapter 9

Understanding Complex Networks

Guide to Networking Essentials, Fifth Edition



Explain how to implement a multivendor network

Discuss the differences between centralized and
client/server computing

Define the client/server networking environment

Discuss the basics of Web
based computing

Guide to Networking Essentials, Fifth Edition


Implementing Multivendor Solutions

For a multivendor environment to work effectively,
server’s OS, clients’ OSs, and redirectors must be

Different OSs use different methods to access files
across a network: CIFS, SMB, NFS, AFP, NCP

Two basic ways to get the file systems from different
OSs to communicate: from the client end and from
the server end

Depends on which vendors’ products to interconnect

Guide to Networking Essentials, Fifth Edition


Based Solutions

Guide to Networking Essentials, Fifth Edition


Based Solutions (continued)

Guide to Networking Essentials, Fifth Edition


Based Solutions (continued)

Guide to Networking Essentials, Fifth Edition


Based Solutions

To implement a
based multivendor
, software must be loaded on the server to
provide services for a particular client

If a Windows Server 2003 network includes
Macintosh hosts, the administrator can add Services
for Macintosh to any of the Windows server OSs

Windows Server 2003 NOSs include this service

Then, Macintosh clients can connect to resources on
the Windows server

Similarly, Windows servers can be outfitted with
Windows Services for Unix

Guide to Networking Essentials, Fifth Edition


Vendor Options

Many NOSs are available from vendors such as
Sun, SCO, and IBM

This chapter focuses on the four most popular PC
operating system product vendors: Microsoft,
Linux, Novell, and Apple

In an effort to ease connectivity between different
NOSs, these companies include utilities in their OSs
to allow simple connectivity between clients and
servers from different vendors

Guide to Networking Essentials, Fifth Edition


Microsoft Redirector

All Windows OSs, starting with Windows for
Workgroups, include the Microsoft redirector, Client
for Microsoft Networks

Designed to access CIFS or SMB
based file systems
across a network

Installing the OS installs the redirector automatically

The server component (File and Printer Sharing for
Microsoft Networks), used for sharing files and
printers via CIFS or SMB, is installed automatically

Allows users of Windows PCs to easily share their
own files and printers with other network users

Guide to Networking Essentials, Fifth Edition


Microsoft in a Novell Network

To connect a Windows client to a Novell NetWare
network running IPX/SPX, NWLink and Client
Service for NetWare (CSNW) must be loaded on
that Windows machine

To connect a Windows Server 2003 system to a
NetWare network, NWLink and Gateway Service
for NetWare (GSNW) must be loaded on server

GSNW allows Windows clients running Client for
Microsoft Networks to access NetWare resources by
using the Windows server as an intermediary

Guide to Networking Essentials, Fifth Edition


DOS Clients

DOS has no built
in network capabilities

Each NOS vendor offers utilities to allow MS
clients to connect to servers of all four types

Microsoft, Novell, Linux, and Apple

Each utility can coexist with other utilities to provide
DOS client connections to all servers

In an Apple Macintosh network: AppleShare PC
software, LocalTalk card

In Linux
based network: Sun Microsystem’s PC
NFS, or Linux can run Samba

Guide to Networking Essentials, Fifth Edition


Novell Networks

NetWare provides file/print services for other OSs

Windows clients: Microsoft Client for NetWare or
Novell Client

Macintosh clients: Novell Client for Mac OS; if
necessary, NetWare servers can support AppleTalk

With Novell NFAP, Windows CIFS/SMB clients,
UNIX/Linux NFS clients, and Macintosh clients (AFP)
can have network file access to NetWare resources

Novell NetStorage (NetWare 6.5) provides platform
independent access to a NetWare network’s
resources through a Web browser

Guide to Networking Essentials, Fifth Edition


Novell Networks (continued)

Guide to Networking Essentials, Fifth Edition


Linux/UNIX Networks

Network File System (NFS) permits networked
machines to export portions of their file systems

After a
NFS volume

is published on the network,
authorized users can mount it in the local file systems

Mount point

Also supports printer sharing

To access NFS, PC clients need additional SW

Administrators prefer to add
to their Linux
servers instead

open source

and allows Linux/UNIX machines to
masquerade as a native Microsoft network server

Guide to Networking Essentials, Fifth Edition


Apple Macintosh

Included in every Macintosh are the OS files and
the hardware required to communicate in an
AppleTalk network

The AppleShare networking software automatically
provides file sharing and includes a print server
that allows computers to share printers

Guide to Networking Essentials, Fifth Edition


Mac OS X

Mac OS X differs from previous versions

Includes network client software to run in a
Macintosh, Windows, or UNIX environment

Negates the need for Windows servers to install
special services for Macintosh computers or
AppleTalk (provides SMB services)

Built on a UNIX core

compatible support for traditional
Macintosh file sharing through other Macs,
Windows, or NetWare servers providing Macintosh

Guide to Networking Essentials, Fifth Edition


Handheld Computing Environment

There’s no clear HW/SW standard on which to rely

Lack of compatibility between manufacturers

Handheld computers rarely connect to the LAN

Options for connecting include Ethernet, but also
FI, Bluetooth, and serial links

Handhelds connect directly to PCs to synchronize

Maintaining a working and secure environment for
handhelds is a latest challenge for administrators

based SW can handle synchronization,
backup, and application loading for handheld
computers in a company

Guide to Networking Essentials, Fifth Edition


Integrating PDAs into a Corporate

PDAs can run Web browsers, e
mail clients, etc.

The majority come equipped with a Wi
connection, allowing them to synchronize data with
the user’s PC and access corporate data and the
Internet directly through a Wi
Fi access point

Administrators are being asked to set up wireless
access points and special Web content, and even
write new applications to accommodate PDAs

Security is also a concern

Wired Equivalent Privacy (WEP) may not be enough

For more robust security, use WPA or 802.11i

Guide to Networking Essentials, Fifth Edition


Centralized Versus Client/Server

centralized computing
, mainframes perform all

“Dumb” terminals connect directly to the mainframe

PCs and “thin clients” can also access a mainframe

Generally character
based, these applications require
little input from the PC, thin client, or terminal

Traffic increases greatly because for every keystroke,
a packet is sent across the network to the mainframe

Then, mainframe sends a (maybe large) response

Client/server computing is used instead of
centralized computing applications

Guide to Networking Essentials, Fifth Edition


Understanding Terminal Services

Halfway through the Windows NT Server product
cycle and with the release of Windows 2000
Server, Microsoft included
Terminal Services

Makes it possible for older, less capable PCs, thin
clients, or narrow
bandwidth remote users to run
large or complex Windows applications

For each user, the server running Terminal Services
runs a software
based “virtual PC”

The only processing that the local client handles is
user input and displaying program output

Guide to Networking Essentials, Fifth Edition


Understanding Terminal Services

Well suited for:

Providing access to modern Windows applications
on older PCs or thin clients

Providing access to centralized applications or
services (instead of installing them on client PCs)

Allowing remote clients using narrow bandwidth
connections to access powerful Windows

Remotely administering computers

Guide to Networking Essentials, Fifth Edition


Understanding Terminal Services

Guide to Networking Essentials, Fifth Edition


Client Computing

Some OSs include capabilities for thin clients to
connect to the server, access resources, and run
applications, all with considerably fewer resources
than a typical desktop computer

Thin clients add the following benefits to the
computing environment:

No removable storage

No hard drive

Lower total cost of ownership

Guide to Networking Essentials, Fifth Edition


Back to the Future: The Mainframe

The mainframe computers introduced to users in
the late 1950s and early 1960s also introduced the
centralized computing model, which is the basis of
terminal services

Today, certain transaction
intensive applications

such as large
scale airline, hotel, and rental car

work well with mainframes and
terminals (or terminal emulation)

Mainframes continue to be important computing
resources today and for the foreseeable future

Guide to Networking Essentials, Fifth Edition


Client/Server Environment

Client/server model is currently the most popular

Easy to implement and scalable

Client/server computing
generally refers to a
network structure in which the client computer and
server computer share processing requirements

Some services provided by file servers are often not
considered client/server

E.g., shared
file storage

Doesn’t make full use of a server’s potential

Does not solve the problem of network traffic

A prominent use of client/server model is the WWW

Guide to Networking Essentials, Fifth Edition


Client/Server Model in a Database

Database management systems (DBMSs)
are an
example of efficient use of the client/server model

The client uses
Structured Query Language (SQL)
to create requests that the database can understand

Major components

Front end
or client

Back end
or server

Guide to Networking Essentials, Fifth Edition


Client/Server Model in a Database
Environment (continued)

Requesting data from a server in SQL:

The user requests the data

The client software translates that request into SQL

The SQL request is sent across the network to the

The server processes the request

The results are sent back across the network to the
client software

The results are presented to the user

Guide to Networking Essentials, Fifth Edition


Advantages of Working in a
Client/Server Environment

Uses client and server computers more efficiently

Makes better utilization of network bandwidth

Client PC’s configuration can be less complex

Smaller processor and less RAM than server

Drive space can be reserved for local applications

Network bandwidth is conserved (in contrast to a
file database application)

Centralized location

Better for security and backup process

Guide to Networking Essentials, Fifth Edition


Based Computing Environments

Many traditional OSs make file and print services
available over a standard Web browser

NetWare’s NetStorage

WebDAV allows a Web browser to carry out
traditional file system tasks


offer businesses access to their tools and
applications through a Web browser

Customers pay as they go for using the application

Developed using standards as Java and XML

Reduces reliance on in
house IT staff

Guide to Networking Essentials, Fifth Edition



Interconnectivity between multiple
vendor operating
systems is often necessary in networking

A client
based multivendor network environment
relies on the client computer’s redirectors to decide
which server should be sent the request

In a server
based solution, the server supports
multiple client types

Using the processing power of a mainframe computer
creates a centralized computer environment

Guide to Networking Essentials, Fifth Edition


Summary (continued)

based terminal services can provide useful
access to networks and centralized server
resources for remote users or single
use workstations

Handheld computing environment is growing rapidly

In a client/server computing environment, the PC and
server share processing and use the resources of
both machines more efficiently

Most DB management systems use SQL for queries

The trend in today’s networking environment is to
remove the obstacles and incompatibilities of working
in a multivendor environment