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INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES. Chapter 2. Networks and and communication protocols. CONTENT. HISTORY Centralized Processing (1960 - 1970) Networks (1970 - 1980) Inter-networks (1980 - 1990) Internet: Network of networks RECALLS ON NETWORK SYSTEMS

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INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

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  1. INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES Chapter 2. Networks and and communication protocols

  2. CONTENT • HISTORY • Centralized Processing (1960 - 1970) • Networks (1970 - 1980) • Inter-networks (1980 - 1990) • Internet: Network of networks • RECALLSONNETWORK SYSTEMS • OSI vs TCP/IP • THE SEVEN OSI LAYERS • OSI’s PROTOCOLS DATA TRANSMISSION • TCP/IP MODEL • TCP/IP NETWORKS SERVICES • WHAT ABOUT NETWORKS? • INTERCONNECTED NETWORKS • LOCAL NETWORKS STANDARDS • IRQ (Interrupted Request) AND ERRORS PROCESSING • SEQUENCE NUMBERS • FLOW CONTROL MECHANISMS • THE NETWORK LAYER • SWITCHING TECHNIQUES • ROUTING • TCP/IP • TCP/IP PROTOCOLS • THE IP PROTOCOL • IP ADRESSES • THE TCP PROTOCOL • THE UDP PROTCOL • SERVICES DEDICATED PORTS A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  3. NETWORKS HISTORY • The steps towards Internet : • Centralized Processing (1960 - 1970) • Networks (1970 - 1980) • Inter-networks (1980 - 1990) • Internet: Network of networks A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  4. Mainframe Host A Mini-computer Host B terminal Remote terminal R.V.A. Centralized Processing (1960 - 1970) A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  5. Networks (1970 - 1980) Token Ring Ethernet A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  6. Ethernet Token Ring Serial WAN Connexion FDDI Inter-networks (1980 - 1990) A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  7. Internet: Network of networks ATM Switcher Router A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  8. Machine B Machine A layer N+1Protocol Layer N+1 Layer N+1 Layer N+1/NInterface layer NProtocol Layer N Layer N RECALLSONNETWORK SYSTEMS • The reference model for open systems interconnection is OSI. • Used to structured communication software components. • Created by the International Standard Organisation ISO. • Intended to enable interoperablity between protocols • and between networks applications. • OSI model: A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  9. THE SEVEN OSI LAYERS Protocole d'application : FTP, SMTP, HTTP, SIP Application 7 Application Message Presentation protocol: XDR, CORBA Présentation Présentation 6 Message Session protocol: TCP 5 Session Session Message Transport protocole: TCPUDP 4 Transport Transport Message 3 Network Network Network Network Paquet 2 Frame Data link Data link Data link Data link Physical 1 Physical Physical Bit Physical Device A Device B Sub-network Mostly used as framework for other network architectures. e.g TCP IP A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  10. OSI versus TCP IP • THE SEVEN OSI LAYERS • OSI’s PROTOCOLS DATA TRANSMISSION • TCP/IP MODEL • TCP/IP NETWORKS SERVICES

  11. Layer Transmitted Received Layer 7 protocol m m 7 interface 6/7 interface 6/7 Layer6 protocol M M 6 interface 5/6 interface 5/6 Layer5 protocol M M 5 Layer4 protocol E M E M E M E M 4 4 1 4 1 4 2 4 2 Layer3 protocol 3 E E M E E M E M E E M E 3 4 1 3 4 2 3 4 1 3 4 2 Layer2 protocol E E E M Q E E E M Q E E E M Q E E E M Q 2 2 3 4 1 2 2 3 4 2 2 2 3 4 1 2 2 3 4 2 2 1 DEVICES - Receiver Sender OSI’sPROTOCOLS  DATA TRANSMISSION • Following a downstream flow (up to down): • Every layer receives data from the upper layer, adds its own control • informations (overheads) before transmitting the new message to the • bottom layer A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  12. OSI versus TCP/IP • ISO has started recommended OSI by end of 70’s • TCP IP was already adopted and in use • There are very few OSI-based systems running • Nearly all the networking softwares and protocols are built on TCP IP model • OSI specifications are very complicated to implement as compare to TCP IP. • OSI is a 7 layers model and TCP IP, 5. • OSI is has a better description of networks and its services. A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  13. TCP/IP MODEL Application Application OSI 5-7 OSI 4 TCP UDP OSI 3 IP Hardware/Wired interfaces OSI 1-2 Internet softwares are built on TCP/IP model A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  14. TCP/IP NETWORKS SERVICES • The TCP/IPlayers controls the network and achieve the following tasks: • Data switching, • Packets routing • Flow control • Connexions,... • Two types of services are offered: • Datagram or best effort. • Virtual circuit or reliable delivery C A D B Datagram C A D B Virtual Circuit (V.C) A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  15. WHAT ABOUT NETWORKS? • INTERCONNECTED NETWORKS • LOCAL NETWORKS STANDARDS • IRQ (Interrupted Request) AND ERRORS PROCESSING • SEQUENCE NUMBERS • FLOW CONTROL MECHANISMS • THE NETWORK LAYER • SWITCHING TECHNIQUES • ROUTING

  16. Modem 101001 Modem PSTN 101001 M M Mux Sub-network (e.g. X.25) Satellite R R R B INTERCONNECTED NETWORKS • Components of a network • Repeater • Bridge • Router • Gateway • LAN • MAN • WAN A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  17. LOCAL NETWORKS STANDARDS • The official standards for Local networks are IEEE 802 standards • IEEE 802.3 CSMA\CD (Local Area Network e.g Ethernet) • IEEE 802.4 Token Bus • IEEE 802.5 Token Ring • IEEE 802.6 MAN (Metropolitan Area Network) • IEEE 802.11 WLAN (Wireless LAN) • IEEE 802.2 describes Datalink layer. IEEE 802.2 LLC Link Layer Control MAC IEEE 802.3 IEEE 802.4 Token Bus IEEE 802.6 CSMA/CD MAN IEEE 802.5 Token Ring PHYSICAL LAYER A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  18. IRQ (Interrupted Request) AND ERRORS PROCESSING Timeout Timeout Timeout Timeout I(N) I(N) I(N) I(N) Erreur Ack(N) Nack(N) Ack(N) Ack(N) Erreur Erreur Expiré I(N+1) Expiré I(N) I(N) I(N) Ack(N+1) Ack(N) Ack(N) Ack(N) A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  19. Timeout I(0) Livré Ack(N) Erreur Expiré I(0) Ignoré Ack(0) I(1) Livré SEQUENCE NUMBERS • To avoid repeating message transmission: • A counter is used to make the difference between a Frame and the • Frame that comes after: A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  20. FLOW CONTROL MECHANISMS • To control the flow, two techniques are used: • Stop and Wait. • Sliding window • Credits technique: A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  21. THE NETWORK LAYER • Routing consists of conveying data through the network. • All the routing techniques a based on minimal-cost policies: • Proportionnal to the network capacity • Proportionnal to the traffic load of the line • In relation with capacity and load • Equal to the length and amount of paquets in the • waiting queued on this node A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  22. Switching node Hôte Sous-réseau 1 Node 1 SWITCHING TECHNIQUES • When a message is transmitted between two nodes, • it follows a dedicated path. • Sometimes, due to efficiency purposes, a message is cutted • into small pieces • These techniques depend on switches problems. A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  23. SWITCHING TECHNIQUES (2) • Switching modes: • circuits switching • messages switching • paquets switching • cells switching • Routing A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  24. ROUTING If J need to compute its new path towards G, it obtains the best cost through H, that is a total amount Of 18 (JH = 12 et HG = 6). Distributed routing techniques: RIP, OSPF,... New J table gives on the left the distance of the best route and on the rigth column, the next hope to take. A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  25. TCP IP • TCP/IP PROTOCOLS • THE IP PROTOCOL • IP ADRESSES • THE TCP PROTOCOL • THE UDP PROTCOL • SERVICES DEDICATED PORTS

  26. TCP/IP PROTOCOLS FTP,TELNET, SMTP, HTTP APPLICATIONS TCP UDP TRANSPORT IP NETWORK 802.2 LLC Slip, HDLC, PPP DATA LINK Ethernet, Token Ring, ... PHYSICAL Internet softwares are built on TCP/IP model : A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  27. 31 15 0 Type of service Version Header lenght Total IP paquet lenght Paquet identification Relative position Flags Checksum Protocol Lifetime counter Source Adress Destination Adress Bourrage Options Data THE IP PROTOCOL A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  28. 0 32 Network Adress Netid 0 Host Adress Hostid Class A 16 0 32 Network Adress Netid 1 0 Host Adress Hostid Class B 32 24 0 Network Adress Netid Host Adress Hostid 1 1 0 Class C IP ADRESSES 8 A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  29. 31 15 0 Source port Adress Destination port Adress Sequence Number Zone de conrôle d'erreur Acknowledgement number (Checksum) A U S P R E Header lenght Reserved C R Y S S N Sliding window K G N H T D Checksum field Emergency Area Options Bourrage Data THE TCP PROTOCOL A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  30. 31 15 0 Source port Adress Destination port Adress Length Checksum Data THE UDP PROTCOL There is no delivery warranty: best effort A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

  31. Number Name Description 5 RJE Remote Job Entry 7 ECHO Echo 11 USERS Active Users 13 DAYTIME Daytime 20 FTP-DATA File Transfert Data 21 FTP-CONTROL File Transfert Control 23 TELNET Telent 25 SMTP Simple Mail 42 TIME Time 43 NAMESERV Host Name sever 53 NICKNAME Who Is 53 DOMAIN Domain Name Sever 67 BOOTPS Bootstrap Server 68 BOOTPC Bootstrap Client 69 TFTP Trivial FTP 79 FINGER Finger 80 HTTP Web Server 102 ISO-TSAP ISO transport 103 X400 X400 SERVICES DEDICATED PORTS Source and destination port adresses are the applications’ access points,. TCP identify an application with its dedicated port number A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

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