SEQ7.PPT

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  • SEQ7.PPT

    1. 1. Computers, Networks & Internet <ul><li>Lecture 7 </li></ul><ul><li>Network Server </li></ul>© ENIC 1998 by Pierre Vincent
    2. 2. Summary <ul><li>Role of a server </li></ul><ul><li>Performance enhancement </li></ul><ul><li>Client server organisation </li></ul><ul><li>Network installation steps </li></ul>
    3. 3. Role of a server
    4. 4. Role of a server <ul><li>The server allows to re-organise the use of microcomputers </li></ul><ul><li>The server gives an economy of scale </li></ul><ul><ul><li>at the ressources level by sharing : </li></ul></ul><ul><ul><ul><li>disk space </li></ul></ul></ul><ul><ul><ul><li>memory space </li></ul></ul></ul><ul><ul><ul><li>devices </li></ul></ul></ul><ul><ul><ul><li>software </li></ul></ul></ul><ul><ul><ul><li>communication links (modem, fax, internet access) </li></ul></ul></ul><ul><ul><li>at the management level by giving centralized administration of </li></ul></ul><ul><ul><ul><li>use and allocation of disk space </li></ul></ul></ul><ul><ul><ul><li>installation of software and its use </li></ul></ul></ul><ul><ul><ul><li>user accounts </li></ul></ul></ul><ul><ul><ul><li>the use of resources by users (disk, hours of connection) </li></ul></ul></ul>
    5. 5. Different views of the network <ul><li>The user's view : </li></ul><ul><ul><li>the server offers resources to the user </li></ul></ul><ul><li>the administrator's view : </li></ul><ul><ul><li>managing access rights to shared resources </li></ul></ul>
    6. 6. Different operating systems Different types of user stations <ul><li>OS2-Warp </li></ul><ul><li>MSDOS </li></ul><ul><li>Windows 3.11 </li></ul><ul><li>WindowsNT </li></ul><ul><li>MacIntosh-System7 </li></ul>
    7. 7. Message exchange mechanism <ul><li>Commands from client to server </li></ul><ul><li>Replies from the server </li></ul><ul><li>Specification of message format (NetBios) </li></ul>
    8. 8. Physical level <ul><li>Storage devices </li></ul><ul><ul><li>read-write: important disk on server, important core memory </li></ul></ul><ul><ul><li>read-only : CD Rom </li></ul></ul><ul><li>Printers </li></ul><ul><ul><li>connected to the parallel port of the server </li></ul></ul><ul><ul><li>in-line and shared on a station </li></ul></ul><ul><ul><li>connected to the network with the help of an internal Ethernet board </li></ul></ul>
    9. 9. Logical level <ul><li>Data file and executable file sharing </li></ul><ul><li>Centralisation of data </li></ul><ul><li>Software (protection and control of the number of releases used) </li></ul><ul><li>(judicial or logical tokens) </li></ul><ul><li>Network oriented applications </li></ul>
    10. 10. The server from point of view of the user <ul><li>Using the shared resources of the server according to access rights rules </li></ul><ul><li>Command : NET USE name_local name_of_the_resource_ </li></ul><ul><ul><li>example : net use prn: 86laser or net use e: 86dosapps </li></ul></ul><ul><li>On the local server </li></ul><ul><ul><li>local name -shared name </li></ul></ul>
    11. 11. Security <ul><li>The server may be used to implement a security policy </li></ul><ul><li>Two levels of access rights management </li></ul><ul><ul><li>Security at the user level (management of users) </li></ul></ul><ul><ul><ul><li>declaration of users </li></ul></ul></ul><ul><ul><li>Security at file level (management of files) </li></ul></ul><ul><ul><ul><li>allocation of the disk space </li></ul></ul></ul><ul><ul><ul><li>access rigths to each file </li></ul></ul></ul><ul><ul><li>Access rigths to each ressource </li></ul></ul>
    12. 12. Domains <ul><li>Grouping of logical resources </li></ul><ul><ul><li>users </li></ul></ul><ul><ul><li>ressources </li></ul></ul><ul><ul><li>servers </li></ul></ul><ul><li>Domains become useful with more than100 users </li></ul><ul><li>The new perspective is the use of a directory system (LDAP, ActiveDirectory). </li></ul>
    13. 13. Types of access rights <ul><li>R - Reading </li></ul><ul><li>W - Write </li></ul><ul><li>C - Creation </li></ul><ul><li>D - Deleting </li></ul><ul><li>X - Running </li></ul><ul><li>A - Modification of attributes (MS DOS: + - R , Hidden) </li></ul><ul><li>P - Modification of permissions </li></ul><ul><li>Y - equal to RWCDA </li></ul><ul><li>N - Null </li></ul>
    14. 14. Protocols Netware, NFS, Windows NT, Web Server Application Local BIOS or NetBIOS Session TCP, IPX, OSI/TP Transport NetBeui, IP, OSI , XNS, IPX (routable or not) Network LLC, HDLC or PPP (MAC depending on support) Data Ethernet, Token ring, Token bus, FDDI Physical
    15. 15. Different services of a network-server <ul><li>Messaging </li></ul><ul><li>Sharing the processing capacity </li></ul><ul><li>Protection against data loss </li></ul><ul><ul><li>files or directory copy (mirroring, disk arrays) </li></ul></ul><ul><li>Bootstrapping from distant workstations </li></ul><ul><li>Approving user interconnection </li></ul><ul><li>Network surveillance - audit of activity </li></ul><ul><li>Time service </li></ul><ul><li>Encryption of data </li></ul>
    16. 16. Performance enhancement
    17. 17. Different methods <ul><li>Improve hard disks and/or memory on stations </li></ul><ul><li>Use of a powerful hard disk on the server </li></ul><ul><li>Memory extension </li></ul><ul><li>Extension of the size of buffers </li></ul><ul><li>Use of a faster processor </li></ul><ul><li>Network segmentation </li></ul><ul><li>Use of only one transmission protocol </li></ul>
    18. 18. Caches at different levels <ul><li>Processor register-memory </li></ul><ul><li>Processor cache -memory cache </li></ul><ul><li>Central memory - hard disk </li></ul><ul><li>Logical cache </li></ul><ul><li>Network cache </li></ul><ul><ul><li>data-server </li></ul></ul><ul><ul><li>mirrors </li></ul></ul><ul><ul><li>routing </li></ul></ul><ul><ul><li>web proxy caches </li></ul></ul>
    19. 19. Client server organisation
    20. 20. Server levels <ul><li>Machine with HD </li></ul><ul><li>Local operating system </li></ul><ul><li>Network board with driver </li></ul><ul><li>Software management of server resources </li></ul><ul><ul><li>shared resources </li></ul></ul><ul><li>user accounts </li></ul>
    21. 21. Client station levels <ul><li>Computer + Bios + NetBios </li></ul><ul><li>Local operating system </li></ul><ul><li>Network interface card with driver </li></ul><ul><li>Interpretation of commands </li></ul><ul><li>Transmission and reception buffer management </li></ul>
    22. 22. Local command Distant commands dir c: net view, dir e:, e:tc Redirector Request to the local OS Request to the network Local execution Distant execution Local answer Distant answer Redirection mechanism
    23. 23. NetBIOS information circulation Application Redirection DOS Session Bios NetBios Local driver Network Driver Peripherical Network
    24. 24. Network installation steps
    25. 25. Network installation steps <ul><li>Installation of network boards and wiring </li></ul><ul><li>Installation of the server's operating system </li></ul><ul><li>Server system configuration </li></ul><ul><li>Installation of the network manager if necessary </li></ul><ul><li>Installation of workstations (DOS, OS2, Windows, W95, WNT) </li></ul><ul><li>Installation of supplementary services </li></ul><ul><li>Creation of users and shared resources </li></ul><ul><li>The installation of a board on a micro or a server requires </li></ul><ul><ul><li>Compatibility at the level of the extension bus </li></ul></ul><ul><ul><li>A driver adapted to the operating system of the server </li></ul></ul>
    26. 26. Installed network operating systems '97 <ul><li>Netware 55 % </li></ul><ul><li>Unix 27 % </li></ul><ul><li>NT 16 % </li></ul><ul><li>OS2 2 % </li></ul>

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