Computers, Networks & InternetComputers, Networks & Internet

Lecture 7Lecture 7

Network ServerNetwork Server

© ENIC 1998© ENIC 1998

by Pierre Vincentby Pierre Vincent

SummarySummary

• Role of a serverRole of a server

• Performance enhancementPerformance enhancement

• Client server organisationClient server organisation

• Network installation stepsNetwork installation steps

Role of a serverRole of a server

Role of a serverRole of a server• The server allows to re-organise The server allows to re-organise

the use of microcomputersthe use of microcomputers• The server gives an economy of The server gives an economy of

scalescale– at the ressources level by sharing :at the ressources level by sharing :

» disk spacedisk space» memory spacememory space» devicesdevices» softwaresoftware» communication links communication links

(modem, fax, internet access)(modem, fax, internet access)– at the management level by giving at the management level by giving

centralized administration ofcentralized administration of» use and allocation of disk use and allocation of disk

spacespace» installation of software and its installation of software and its

useuse» user accountsuser accounts» the use of resources by users the use of resources by users

(disk, hours of connection)(disk, hours of connection)

Different views of the networkDifferent views of the network

• The user's view :The user's view :– the server offers resources to the the server offers resources to the

useruser

• the administrator's view :the administrator's view :– managing access rights to managing access rights to

shared resourcesshared resources

Different types of user stationsDifferent types of user stations

• OS2-WarpOS2-Warp

• MSDOSMSDOS

• Windows 3.11Windows 3.11

• WindowsNTWindowsNT

• MacIntosh-System7MacIntosh-System7

Different operating systemsDifferent operating systems

Message exchange mechanismMessage exchange mechanism

• Commands from client to server Commands from client to server

• Replies from the serverReplies from the server

• Specification of message format Specification of message format (NetBios)(NetBios)

Physical levelPhysical level

• Storage devicesStorage devices– read-write: important disk on read-write: important disk on

server, important core memoryserver, important core memory

– read-only : CD Romread-only : CD Rom

• PrintersPrinters– connected to the parallel port ofconnected to the parallel port of

the serverthe server

– in-line and shared on a stationin-line and shared on a station

– connected to the network with the connected to the network with the help of an internal Ethernet boardhelp of an internal Ethernet board

Logical levelLogical level

• Data file and executable file Data file and executable file sharingsharing

• Centralisation of dataCentralisation of data

• Software Software (protection and control of the (protection and control of the number of releases used)number of releases used)

• (judicial or logical tokens)(judicial or logical tokens)

• Network oriented applications Network oriented applications

The server fromThe server frompoint of view of the userpoint of view of the user

• Using the shared resources of the Using the shared resources of the server according to access rights rulesserver according to access rights rules

• Command : Command : NET USE name_local NET USE name_local name_of_the_resource_name_of_the_resource_

– example : net use prn: \\486\laser example : net use prn: \\486\laser or net use e: \\486\dosappsor net use e: \\486\dosapps

• On the local serverOn the local server– local name -shared namelocal name -shared name

SecuritySecurity

• The server may be used to The server may be used to implement a security policy implement a security policy

• Two levels of access rights Two levels of access rights management management

– Security at the user level Security at the user level (management of users)(management of users)

» declaration of usersdeclaration of users

– Security at file level Security at file level (management of files)(management of files)

» allocation of the disk spaceallocation of the disk space

» access rigths to each fileaccess rigths to each file

– Access rigths to each ressourceAccess rigths to each ressource

DomainsDomains

• Grouping of logical resources Grouping of logical resources – usersusers

– ressourcesressources

– serversservers

• Domains become useful with more Domains become useful with more than100 usersthan100 users

• The new perspective is the use of The new perspective is the use of a directory system a directory system (LDAP, ActiveDirectory).(LDAP, ActiveDirectory).

Types of access rightsTypes of access rights

• R - ReadingR - Reading

• W - WriteW - Write

• C - CreationC - Creation

• D - DeletingD - Deleting

• X - RunningX - Running

• A - Modification of attributes A - Modification of attributes (MS DOS: + - R , Hidden)(MS DOS: + - R , Hidden)

• P - Modification of permissionsP - Modification of permissions

• Y - equal to RWCDAY - equal to RWCDA

• N - NullN - Null

ProtocolsProtocols

Netware, NFS,Netware, NFS,Windows NT, WebWindows NT, Web

ServerServerApplicationApplication

Local BIOSLocal BIOSor NetBIOSor NetBIOSSessionSession

TCP, IPX, TCP, IPX, OSI/TPOSI/TPTransportTransport

NetBeui, IP, OSI , XNS, IPXNetBeui, IP, OSI , XNS, IPX(routable or not)(routable or not)NetworkNetwork

LLC, HDLC or PPP LLC, HDLC or PPP (MAC depending on support)(MAC depending on support)DataData

Ethernet, Token ring, Ethernet, Token ring, Token bus, FDDIToken bus, FDDIPhysicalPhysical

Different services of a network-serverDifferent services of a network-server

• MessagingMessaging

• Sharing the processing capacitySharing the processing capacity

• Protection against data lossProtection against data loss– files or directory copy files or directory copy

(mirroring, disk arrays)(mirroring, disk arrays)

• Bootstrapping from Bootstrapping from distant workstationsdistant workstations

• Approving user interconnectionApproving user interconnection

• Network surveillance - audit of Network surveillance - audit of activityactivity

• Time serviceTime service

• Encryption of dataEncryption of data

PerformancePerformanceenhancementenhancement

Different methodsDifferent methods

• Improve hard disks and/or memory Improve hard disks and/or memory on stationson stations

• Use of a powerful hard disk on Use of a powerful hard disk on the serverthe server

• Memory extensionMemory extension

• Extension of the size of buffersExtension of the size of buffers

• Use of a faster processorUse of a faster processor

• Network segmentationNetwork segmentation

• Use of only one transmission Use of only one transmission protocolprotocol

Caches at different levelsCaches at different levels

• Processor register-memoryProcessor register-memory

• Processor cache -memory cacheProcessor cache -memory cache

• Central memory - hard diskCentral memory - hard disk

• Logical cacheLogical cache

• Network cacheNetwork cache– data-serverdata-server

– mirrorsmirrors

– routingrouting

– web proxy cachesweb proxy caches

Client server Client server organisationorganisation

Server levelsServer levels

• Machine with HDMachine with HD

• Local operating systemLocal operating system

• Network board with driverNetwork board with driver

• Software management of Software management of server resourcesserver resources

– shared resourcesshared resources

• user accountsuser accounts

Client station levelsClient station levels

• Computer + Bios + NetBiosComputer + Bios + NetBios

• Local operating systemLocal operating system

• Network interface card with driverNetwork interface card with driver

• Interpretation of commandsInterpretation of commands

• Transmission and reception buffer Transmission and reception buffer managementmanagement

Redirection mechanismRedirection mechanismLocal command Distant commands

dir c: net view, dir e:, e:tc

Redirector

Request to the local OS Request to the networkLocal execution Distant executionLocal answer Distant answer

NetBIOS information circulationNetBIOS information circulation

ApplicationApplication

RedirectionRedirection

DOS SessionDOS Session

BiosBios NetBiosNetBios

Local driverLocal driver Network Network DriverDriver

PeriphericalPeripherical NetworkNetwork

NetworkNetworkinstallation stepsinstallation steps

Network installation stepsNetwork installation steps• Installation of network boards and Installation of network boards and

wiringwiring• Installation of the server's operating Installation of the server's operating

systemsystem• Server system configurationServer system configuration• Installation of the network manager Installation of the network manager

if necessaryif necessary• Installation of workstations Installation of workstations

(DOS, OS2, Windows, W95, WNT)(DOS, OS2, Windows, W95, WNT)• Installation of supplementary Installation of supplementary

servicesservices• Creation of users and shared Creation of users and shared

resourcesresources• The installation of a board on a The installation of a board on a

micro or a server requiresmicro or a server requires– Compatibility at the level of the Compatibility at the level of the

extension busextension bus– A driver adapted to the operating A driver adapted to the operating

system of the serversystem of the server

Installed network operating systems Installed network operating systems '97 '97

• NetwareNetware 55 % 55 %

• UnixUnix 27 % 27 %

• NTNT 16 % 16 %

• OS2OS2 2 % 2 %