Network Operations

1
Chapter 11

• Network Operations

2
Introduction

• Topics
• Network Operating Systems
• Software Components of Networking
• Installing a Network Operating System
• Understanding Basic Network Services

3
Network Operating Systems

• Early systems (UNIX) were essentially multi-user
  systems
• In the early 1980s, NOSs were mainly research
  projects (Xerox research)
• Early Microsoft systems (LAN Manager) were
  add-ons to standalone operating systems

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Network Operating Systems

• The first networks allowed data exchange by means
  of a basic network protocol
• Application programs used the network to share
  data for specific purposes
• Berkeley Unix (BSD) successfully integrated
  networking extensions into an operating system in
  the late 60s

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Network Operating Systems

• Initially users could only use a computer on
  which they had an account
• Users need multiple accounts to work on different
  computers
• Files were transferred by hand
• Users shared accounts and multiple versions of
  the same file existed on different computers

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Early Network Operating Systems

• The SunOs
• was an early NOS that overcame previous NOS
  limitations
• Supported a network file system for
  electronically sharing files
• Had a directory service

7
Commonly Available Network Operating Systems

• Linux
• Novell NetWare
• SunOS/Solaris
• FreeBSD
• Unix
• Windows

8
Network Operating Systems Functions

• Basic NOS Functions
• Directing and controlling activities of a
  computers hardware components
• Coordinating the interaction between software
  applications and computer hardware
• Provide services to application programs
• Print
• File
• Messaging

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Network Operating Systems

• An NOS
• utilizes device drivers and protocol stacks
• uses one or more servers for access to files and
  shared hardware resources
• coordinates the activities of multiple computers
  across a network

10
Network Operating Systems

• Advertise and manage resources from a centralized
  directory service
• Provide mechanisms to easily add and remove
  services
• Reconfigure the resources
• Can support multiple services of the same kind

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Multitasking

• Provides means for supporting multiple processes
  required by a network
• Types
• Pre-emptive - processes are assigned CPU time
  slices by the operating system
• Cooperative - OS cannot interrupt process
• Pre-emptive multitasking is preferred

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Main NOS Software Components

• Naming and directory services
• Client and server network software
• Drivers and stacks

13
Software Components of Networking

• To communicate systems use a special circuit
  board called a network interface card
• A device driver program must be installed on the
  computer to make it functional

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Device Driver Technologies

• The Network Device Interface System (NDIS)
• Open Data-Link Interface (ODI)
• Win32 Driver model (WDM)
• Every NIC must have at least one protocol stack
  bound to it

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Protocol Stacks

• A protocol stack is a set of network protocols
  that work together to transmit messages
• The TCP/IP protocol stack is the most common
  stack
• TCP/IP stacks have been written for NDIS, ODI and
  WDM driver interfaces

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Client/Server NOSs

• allow the network to centralize services on one
  or more dedicated servers
• require special software
• Client software is simpler than server software
• Server software depends on the type of NOS

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Client/Server NOSs

• Advantages
• Centralization
• Interoperability
• Scalability
• Flexibility
• Hides detail

• Disadvantages
• Expense
• Dependence
• Administration

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Server Functions

• Manages a directory that contains user
  permissions to resources
• Supports file access compatible with various
  client operating systems
• Supports consistent user environment
• Provides interfaces to Internet Services
• Manages shareable mass storage

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Peer-to-Peer Networks

• Advantages
• Less initial expense
• Setup

• Disadvantages
• Decentralization
• Security
• Performance

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Redirection

• Locating resources for a requested service and
  correctly sending request to that location
• accept requests from applications and determines
  whether network access is needed
• Network operating systems depend heavily on
  redirection
• operates at the Presentation layer of the OSI
  model

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NOS Designator

• works in coordination with the redirector and is
  associated with drive mapping
• Many request/reply (client/server) architectures
  are being replaced by event-driven,
  publish/subscribe architectures to achieve real
  item data delivery

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Installing a Network Operating System

• Network services that determine the framework for
  the rest of the network and clients must be
  configured
• Before the server OS is installed numerous
  decisions about how the computer will interact
  with the network must be made

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Installing a Network Operating System

• Considerations
• Function of the server
• File systems to be used
• Naming convention to be used
• Other operating systems and applications
• How data will be stored and protected
• Hardware compatibility

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Installing a Network Operating System

• Common Server Uses
• Logon server
• Network services server
• Application, File or Print server
• Web server
• FTP or News/Usenet (NNTP) server
• E-mail server

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Installing a Network Operating System

• File Systems
• describe the OS method of organizing, managing
  and accessing files through logical structuring
  on the hard drive
• interact with the OS to find files that are
  requested on the hard disk

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Installing a Network Operating System

• Common file systems
• FAT
• HPFS
• NTFS

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FAT File System

• FAT stands for File Allocation Table
• It is simple, reliable, and uses little storage
• Virtual FAT (VFAT) is an enhanced version of the
  FAT file system

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HPFS and NTFS

• HPFS (High-Performance File System)
• designed for the OS/2 operating system
• allows access to larger hard drives
• NTFS (New Technology File System)
• developed for Windows NT and Windows 2000
• provides full security for a Windows file server,
  and to support Macintosh datasets

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Naming Conventions

• Rules for naming network workstations and servers
• It is important to incorporate a scheme for user
  accounts, computers, directories, network shares,
  printers, and servers so there is uniformity and
  logical structure
• They should be descriptive enough to be able to
  locate devices quickly

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Data Storage Schemes - RAID

• RAID (Redundant Array of Inexpensive Disks)
• Determine how data will be stored and protected
• RAID organizes multiple disks into a large, high
  performance logical disk

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RAID Types

• RAID Level 0 disk stripping (no fault
  tolerance)
• RAID Level 1 mirroring and duplexing
• RAID Level 2 Hamming code ECC
• RAID Level 3 parallel transfer with parity
• RAID Level 4 independent disks with shared
  parity disk
• RAID Level 5 distributed parity blocks
• RAID Level 6 two independent parity schemes
• RAID Level 10 high reliability and performance
• Not all operating systems support all versions of
  RAID

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Minimum Requirements

• Microsoft Hardware Compatibility List (HCL) lists
  compatible hardware for their operating systems
• Each operating system has minimum hardware
  requirements

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Steps to Installing a Network Operating System

• Most NOSs are installed from a CD-ROM
• some can be installed over the network from a
  shared directory and a network boot disk
• Setup logs are created when a NOS is installed
  that list problems that caused the install to
  fail
• A final cleanup procedure attempts to delete
  items that were partially installed or left in an
  incomplete state

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Post-Install Procedures

• Configure
• DHCP scope(s)
• WINS
• DNS zones
• Periodically install service packs to keep OS
  current

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Understanding Basic Network Services

• Most NOSs have an administrative tool for
  removing or adding services
• Some services depend on others and stopping one
  can have a detrimental effect on others

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Bindings

• the process of linking different network
  components to enable communication between the
  components
• enable communication between NIC drivers,
  protocols, and services
• Bindings establish a logical link between the
  upper protocols and lower protocols on the NIC to
  provide interoperability

37
Binding Considerations

• The number of protocols run and the order of the
  bindings on the client side can impact network
  performance
• The most frequently used protocol service or
  adapter should be bound first

38
Network Printing

• Three ways to connect a network printer
• via serial/parallel to a server
• via serial/parallel to a remote print server
• via an internal NIC

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Guidelines for Network Printing

• Determine the connection speed
• Install an appropriate amount of RAM in the
  printer
• Deploy an appropriate number of printers
• Locate the printer and print server close to
  users if possible

40
Directory Services

• A database of network services and resources
• Directory services are often replicated and
  partitioned so that services are local to the
  users
• identifies all resources on a network and makes
  them accessible to users and applications
• Makes it easier to locate and manage network
  resources

41
Directory Services Standards

• X.500 directory service
• Lightweight Directory Access Protocol (LDAP)
• LDAP is now incorporated in most vendor releases
  of Linux

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Novell NetWare Directory Services (NDS)

• an object-oriented implementation of directory
  services that allows sophisticated naming schemes
  and databases
• The NDS architecture provides access to all
  network resources regardless of where the
  resources are physically located