guide to networking essentials fifth edition chapter 9 understanding complex networks

Guide to Networking EssentialsFifth Edition

Chapter 9Understanding Complex Networks

Guide to Networking Essentials, Fifth Edition 2

Objectives

• Explain how to implement a multivendor network environment

• Discuss the differences between centralized and client/server computing

• Define the client/server networking environment

• Discuss the basics of Web-based computing environments


Implementing Multivendor Solutions

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

• 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


Client-Based Solutions


Client-Based Solutions (continued)


Server-Based Solutions

• To implement a server-based multivendor solution, 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


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


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


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


MS-DOS Clients

• MS-DOS has no built-in network capabilities

• Each NOS vendor offers utilities to allow MS-DOS clients to connect to servers of all four types—Microsoft, Novell, Linux, and Apple– Each utility can coexist with other utilities to provide

MS-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


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


Novell Networks (continued)


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 Samba to their Linux servers instead

– Is open source and allows Linux/UNIX machines to masquerade as a native Microsoft network server


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


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– Backward-compatible support for traditional

Macintosh file sharing through other Macs, Windows, or NetWare servers providing Macintosh services


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

USB, Wi-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

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


Integrating PDAs into a Corporate Network

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

• The majority come equipped with a Wi-Fi 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


Centralized Versus Client/Server Computing

• In centralized computing, mainframes perform all processing– “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


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


Understanding Terminal Services (continued)

• 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 applications

– Remotely administering computers


Understanding Terminal Services (continued)


Thin-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


Back to the Future: The Mainframe Environment

• 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 applications—work well with mainframes and terminals (or terminal emulation)

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


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


Client/Server Model in a Database Environment

• 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


Client/Server Model in a Database Environment (continued)

• Requesting data from a server in SQL:1. The user requests the data

2. The client software translates that request into SQL

3. The SQL request is sent across the network to the server

4. The server processes the request

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

6. The results are presented to the user


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 shared-file database application)

• Centralized location– Better for security and backup process


Web-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

• ASPs 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


Summary

• 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


Summary (continued)

• Server-based terminal services can provide useful access to networks and centralized server-based 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

guide to networking essentials fifth edition chapter 9 understanding complex networks

Documents

windows clients

windows services

windows serversimilarly

windows machineto

novell netware network

server enddepends

clients oss

network usersguide