chapter 8 simple network operations. guide to networking essentials, fifth edition2 contents...

Chapter 8

Simple Network Operations

Guide to Networking Essentials, Fifth Edition 2

Contents

1. Network Operating Systems

2. Software Components of Networking

3. Installing a Network Operating System

4. Configuring Network Services

5. Network Applications


1. Network Operating Systems

• Network operating system (NOS): OS with functions that facilitate network communication, allow computer resources sharing on a network, and provide access control to those resources– Interface for users and applications to access the

network and its resources– Introduced during the mid-1980s– Handle standalone computer activities as well as

communication over the network– E.g., Novell NetWare, Windows Server 2000/2003,

UNIX, and Linux


Basic Functions of an Operating System

• OS coordinates interaction between software applications and computer hardware

• Most applications are written so that they can be used only with a particular OS family

• Two features necessary in a NOS– Multitasking: capability to support numerous

processes at one time– Time slicing occurs when the CPU’s computing

cycles are divided between more than one task• Human inability to distinguish instances of this brief

time period creates the illusion of multitasking– Every contemporary OS includes these functions


• Two types of multitasking– Preemptive multitasking

– Cooperative multitasking

• A true high-performance NOS must be a preemptive multitasking system– All contemporary operating systems are designed to

use preemptive multitasking

• OSs include many NOS features– Some of these features are still reserved for OSs

designed to be installed on a server computer

2. Software Components of Networking

2.1. Naming Services

2.2. Directory Services

2.3. Client Network Software

2.4. Server Network Software

2.5. Client and Server Capabilities



• NOS manages computer’s activities and provides a network environment– Organizes hardware into an interactive whole– Coordinates/controls functions of

machines/peripherals– Supports security and privacy (network and users)– Controls access to resources (user authentication)– Advertises/manages resources (centralized

directory)– Provide access to shared resources

• NOS components: naming services, directory services, and client and server software


2.1. Naming Services

• On most networks, a name is necessary to identify and access resources of all kinds

• Humans recognize symbolic names more easily than numeric names– Naming services translate symbolic names into

corresponding network addresses

• This chapter explains the relationship between how Microsoft uses NetBIOS names and how the TCP/IP-based Domain Name System uses domain names


2.1.1. NetBIOS Names

• Names can be no longer than 15 characters

• Ending a name with $ prevents it from appearing in the NetBIOS browse list


2.1.2. Universal Naming Convention

• Drive mapping: process of associating a network storage resource with a local drive letter

• Windows and Linux (running Samba) OSs and most other modern NOSs recognize Universal Naming Convention (UNC) paths, a standard method for specifying network resources– \\servername\sharename– In UNC-aware applications and many command-line

activities, a UNC path can be used instead of a drive letter to access a network resource


2.1.3. Domain Names and DNS

• DNS translates symbolic domain names into numeric IP addresses– Permits users to access resources and services by

using symbolic domain names on the Internet

• DNS server maintains a DB of computer name and IP address pairs– At least one DNS server is maintained for a domain– Domain: named logical grouping of network resources

• E.g., course.com– When a network request for www.course.com is

made, the request is sent to the DNS server responsible for the course.com domain


2.2. Directory Services

• Directory service: manages information about network services, resources, users, groups, and objects so that users can access resources and services by browsing or asking for them by type– Manages and controls access to network resources– Access control (stores info and performs checks)– E.g., Windows’ Active Directory, Novell’s eDirectory

• Uses “tree and forest” metaphor to organize contents• Patterned after X.500 directory service

– LDAP is far easier to implement

– Most Linux versions include NIS


2.3. Client Network Software

• Client network SW: part of NOS installed on PCs that access network services or network resources– Most important component is a redirector

• SW component operating at the OSI model’s layer 6 that is found on both client and server NOSs

• Hides from users the complicated tasks involved in accessing network resources

– Designator: aids in network resource interaction• Keeps track of the drive letters assigned locally to

remote or shared drives– A shared drive is known as a share

– Client SW can refer to Internet access applications


2.4. Server Network Software

• Server SW can restrict access to resources by using access controls– Also: user/group management, logon authentication,

network administration, fault tolerance


2.5. Client and Server Capabilities

• Many NOSs (e.g., Windows Server 2003, XP, Vista) include client and server capabilities in both the server and desktop versions– Generally, the desktop version of the NOS is not as

powerful or robust as the server version

• Novell NetWare is strictly a server NOS, so there’s no desktop version of NetWare

• In Linux, the choice between a desktop or server installation is usually made during installation

3. Installing a Network Operating System

3.1. Installation Preparation

3.2. Installing Microsoft Windows Servers

3.3. Installing Novell NetWare 6.5

3.4. Installing Linux



• Installing an NOS is not much different than installing a standard desktop OS– Requires only a few additional steps focused on

configuring the network and the server services – Before installation of an NOS can begin, however,

you must complete a few preparatory steps


3.1. Installation Preparation

• Before you begin an NOS installation, you need to understand the following network aspects:– Size of the network– Job requirements of the server– Organization of storage devices– File systems to be used– Identification or naming convention– Network adapter configuration– Protocol selection– Hardware compatibility


3.1.1. Size of the Network

• The size of a network can affect which services you decide to configure, how many servers you need, and the number of connection licenses you require– A small LAN with fewer than 10 users who require

only file and printer sharing can probably function fine with a peer-to-peer network

• Windows XP or Vista could serve as the OS

– With more users or more advanced networking service requirements, a dedicated server with an NOS designed for servers is definitely in order


3.1.2. Server Job Requirements

• The services and resources hosted by a server determine what components are installed– E.g., DNS, DHCP, Web services, remote access, etc.

• Other server responsibilities– Domain controller: authenticates users and maintains

directory services and the security DB for a domain• For fault tolerance, install at least two per domain

– Member server: hosts a service or resource and doesn’t maintain the directory and security DB

• In NetWare, use existing tree or create new one• In Linux, decide individual services to install


3.1.3. Storage Device Organization

• Crucial to network’s success when accessibility, performance, and fault tolerance are essential

• Partition: logical organization of disk space; each partition appears as a separate logical drive

• Ways to organize NOS host drive– Multiple-boot: good for testing; not good for security– Single-partition, single-NOS: most secure– Multiple-partition, single-NOS: useful for separating

data from OS files; increases drive activity– Fault-tolerant storage: e.g., disk mirroring, RAID


3.1.4. File Systems

• File system: method used to store, organize, and manage access to files on a mass storage device– File systems differ in how they allocate space, how

files are located on disk, the level of fault tolerance, and how access to files is secured

• Fault-tolerant features include backup copies of FAT, journaling

• Folder- and/or file- level security are important– E.g., as provided by NTFS or ext3– It’s best to use the most secure file system available for

the OS you’re installing


3.1.5. Naming Conventions

• Naming convention: method of creating names– Should have scheme for user accounts, computers,

directories, network shares, printers, and servers– Common naming schemes

• Construct user names from the user’s first and last names, plus a code identifying job title or department

• Construct group names from resource types, department names, location names, project names

• Construct computer names for servers and clients from their department, location, and an ID number

– Must be consistent, easy to use and understand, and must enable clear object identification


3.1.6. Network Adapter Configuration

• The NIC is the primary communication device between a computer and the rest of the network– A computer purchased as a server already has an

NIC installed• Must verify manufacturer and model number to ensure

compatibility and update device drivers as necessary

• Most NICs are plug-and-play-compatible with the OS, so NIC configuration isn’t usually necessary

– Verify compatibility with the OS version you are using, and have a driver disk ready in case the OS doesn’t recognize the NIC


3.1.7. Protocol Selection

• Protocol and configuration options must be compatible for computers to communicate– For example, TCP/IP requires the following pieces of

information before NOS installation begins:• IP address

• Subnet mask

• Default gateway

• DNS

• WINS

• DHCP


3.1.8. Hardware Compatibility

• HW components of the computer on which it’s installed must be compatible with the NOS– If you use incompatible hardware, the vendor might

not provide technical support– Double-check that your computer’s HW components

are fully compatible with the NOS• Microsoft publishes the Windows Catalog

– Formerly called the Hardware Compatibility List (HCL)

• Linux distributors publish a similar list for the various Linux versions

• Novell typically certifies whole systems as NetWare compatible


2.3. Installing Microsoft Windows Servers

• Windows server versions are not much more difficult to install than Windows XP or Vista

• With the proper preparation, the Setup Wizard makes the installation process as simple as entering a few key data items– The major steps or sections of the installation

included here give you insight into the architecture and simplicity of the Windows server line of operating systems


3.2.1. Beginning the Installation


3.2.2. Text-Based Phase


3.2.3. GUI Phase

• In the GUI phase, you use a mouse or keyboard to enter items or make selections

• You define computer and domain names, enter the identification key from installation CD, select the server type (domain controller or member server), assign a password to Administrator account, select environment and desktop components

• Setup copies some files from the temporary folder to the destination folder and then moves into the network setup phase


3.2.4. Network Setup Phase

• You install drivers for the NIC, select and configure protocols, and review bindings

• Upon completion, files are copied to the system folder and temporary folder is deleted– Next, you define time zone and display settings– Then, the computer restarts, the Administrator logs

on, and the Configure Server Wizard starts• Allows the server to be configured as a domain

controller, member server, or standalone server– If server is to act as a domain controller, Active

Directory is installed and configured


3.3. Installing Novell NetWare 6.5

• Install NetWare by using one of two methods– Over the network– From a CD

• The primary install utility is INSTALL.NLM– Two phases

• Text mode– Create partitions, accept license agreement, copy files,

install storage device drivers, and select NIC drivers

• GUI mode– Assign server name, set up protocols, and install

eDirectory


3.4. Installing Linux

4. Configuring Network Services

4.1. Installing, Removing, and Configuring Network Services

4.2. Network Bindings

4.3. Network Printing

4.4. File Shares



• Network services, the basic resources on all networks, are the foundation of network applications

• The two most basic shared network resources (network services) are printers and file folders

• You can add numerous capabilities, resources, and delivery methods to a default NOS installation– Groupware applications, e-mail packages, shared

whiteboard applications, Web servers, etc.


4.1. Installing, Removing, and Configuring Network Services


4.2. Network Bindings

• Binding: process of linking network components from various levels of the network architecture to enable communication between those components – Associate upper-layer services and protocols to

lower-layer network adapter drivers– Many NOSs enable all valid bindings by default

• Often results in some performance degradation

• Binding order should enhance the computer’s use of the network– Bind the most frequently used protocol, service, or

adapter first to speed network connections


4.3. Network Printing

• It is one of the two essential network services

• Redirector intercepts print requests and forwards them to the right print servers or network printers

• Three components: the print server, the print queue, and the printer– First, installing a printer on a server or as a direct

network-connected device– Next, share printer’s logical representation in NOS– Print queue is a storage location that accepts print

jobs from network clients and stores the print job until the printer is available to print it


4.3.1. Printer Management

• On most networks, you manage printers from local direct access or through the network printer share– Sometimes you may use a Web browser (e.g., IPP)

– Must have right level of access granted to user

– Printer management covers wide range of activities• Granting and restricting user access to printers

• Monitoring the print queue for proper functioning

• Limiting access (time frame, department, or priority)

• Updating local and remote printer drivers

• Maintaining printers

• Managing printers remotely


4.3.2. Sharing Fax Modems

• This feature is not often a default component in an NOS; many third-party vendors offer add-on products to share a fax modem over a network– With these add-on products, clients can fax

documents from the desktop– You can manage and administer fax shares just like

printer shares– Usually, additional client-installed software is needed

to connect to a fax share• After drivers are installed, there’s no major difference

between using a printer share and a fax share


4.4. File Shares

5. Network Applications

5.1. E-Mail or Messaging

5.2. Scheduling or Calendaring

5.3. Groupware



• Network applications: designed for multiple simultaneous users on computers on a network

• Three types of essential network applications: messaging, scheduling, and groupware

• Pros– Much easier to administer (e.g., on large networks)– Save money

• Cons– Poor network performance degrades performance– If network is down, application is often unusable


• At least three types of architectures for network applications– Centralized– File-system sharing– True client/server


5.1. E-Mail or Messaging

• Most popular network application

• E-mail is fast and asynchronous

• Based on a common protocol and standards for communication– Post Office Protocol version 3 (POP3)– Simple Mail Transport Protocol (SMTP)– Internet Message Access Protocol (IMAP)– X.400– X.500– Message Handling System (MHS)


5.2. Scheduling or Calendaring

• A network scheduler is an electronic form of an appointment book and to-do lists– Most offer private and public calendars, appointment

books, task lists, and contact/address books– They can also notify about upcoming meetings, warn

about overlapped schedules, and offer reminders of special events or the need to contact someone

– Most offer integration into e-mail programs and office-productivity suites

– To supplement or replace a paper-based personal information manager, schedules can be printed


5.3. Groupware

• Groupware enables multiple users to interact with a single file, document, or project– E.g., an entire department can contribute to a

document’s production and watch as the groupware combines everyone’s input into a single document

– Examples: multiuser multimedia authoring tools, Lotus Notes, Novell Virtual Office, and HP’s TeamLinks

– Some make it possible to collaborate across the Internet

– The biggest explosion in groupware products is integrating PDAs with corporate networks


Summary

• Network operating system (NOS): controls the operations of a computer, including local hardware activity as well as communication over network media– Enables sharing resources, managing peripherals,

maintaining security, and controlling user access

• Client network software on workstations allows users to take advantage of network resources– Doesn’t always mean redirectors and designators

• Server network software is designed to host resources so that multiple clients can access them


• Installing an NOS is similar to installing any OS– Issues you must be aware of include size of the

network, job requirements of the server, storage device organization, naming conventions, NIC and protocol selection and configuration, and hardware compatibility

– The steps for installing Windows Server 2000/2003, Novell NetWare, and Linux are similar

• Two fundamental network services: sharing printers and sharing files

• Some standalone applications have been revised to function as cross-network applications

chapter 8 simple network operations. guide to networking essentials, fifth edition2 contents...

Documents