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

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Presentation on theme: "1 Chapter 2. Networks and and communication protocols INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES."— Presentation transcript:

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

2 2 CONTENT 1.HISTORY oCentralized Processing (1960 - 1970) oNetworks (1970 - 1980) oInter-networks (1980 - 1990) oInternet: Network of networks 2.RECALLS ON NETWORK SYSTEMS 3.OSI vs TCP/IP oTHE SEVEN OSI LAYERS oOSIs PROTOCOLS DATA TRANSMISSION oTCP/IP MODEL oTCP/IP NETWORKS SERVICES A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES 4.WHAT ABOUT NETWORKS? oINTERCONNECTED NETWORKS oLOCAL NETWORKS STANDARDS oIRQ (Interrupted Request) AND ERRORS PROCESSING oSEQUENCE NUMBERS oFLOW CONTROL MECHANISMS oTHE NETWORK LAYER oSWITCHING TECHNIQUES oROUTING 5.TCP/IP oTCP/IP PROTOCOLS oTHE IP PROTOCOL oIP ADRESSES oTHE TCP PROTOCOL oTHE UDP PROTCOL oSERVICES DEDICATED PORTS

3 3 NETWORKS HISTORY oThe steps towards Internet : oCentralized Processing (1960 - 1970) oNetworks (1970 - 1980) oInter-networks (1980 - 1990) oInternet: Network of networks A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

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

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

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

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

8 8 RECALLS ON NETWORK SYSTEMS The reference model for open systems interconnection is OSI. oUsed to structured communication software components. oCreated by the International Standard Organisation ISO. oIntended to enable interoperablity between protocols and between networks applications. OSI model: Machine A Machine B Layer N+1 layer N+1 Protocol layer N Protocol Layer N+1/N Interface Layer N+1 Layer N A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

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

10 10 OSI versus TCP IP oTHE SEVEN OSI LAYERS oOSIs PROTOCOLS DATA TRANSMISSION oTCP/IP MODEL oTCP/IP NETWORKS SERVICES

11 11 OSIs PROTOCOLS 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 12 OSI versus TCP/IP ISO has started recommended OSI by end of 70s 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 13 TCP/IP MODEL Application TCP Application UDP IP Hardware/Wired interfaces OSI 5-7 OSI 4 OSI 3 OSI 1-2 Internet softwares are built on TCP/IP model A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

14 14 TCP/IP NETWORKS SERVICES The TCP/IP layers 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 A B D C Datagram A B D C Virtual Circuit (V.C) A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

15 15 WHAT ABOUT NETWORKS? oINTERCONNECTED NETWORKS oLOCAL NETWORKS STANDARDS oIRQ (Interrupted Request) AND ERRORS PROCESSING oSEQUENCE NUMBERS oFLOW CONTROL MECHANISMS oTHE NETWORK LAYER oSWITCHING TECHNIQUES oROUTING

16 16 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 17 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 Link Layer Control IEEE 802.3 CSMA/CD IEEE 802.4 Token Bus IEEE 802.5 Token Ring IEEE 802.6 MAN MAC LLC PHYSICAL LAYER LOCAL NETWORKS STANDARDS A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

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

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

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

21 21 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 THE NETWORK LAYER A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

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

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

24 24 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,... ROUTING A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES New J table gives on the left the distance of the best route and on the rigth column, the next hope to take.

25 25 TCP IP oTCP/IP PROTOCOLS oTHE IP PROTOCOL oIP ADRESSES oTHE TCP PROTOCOL oTHE UDP PROTCOL oSERVICES DEDICATED PORTS

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

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

28 28 8 0 0 24 32 Network Adress Netid Host Adress Hostid 11 Class A Class B Class C 0 16 Network Adress Netid Host Adress Hostid 10 32 0 Network Adress Netid Host Adress Hostid 0 32 IP ADRESSES A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES

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

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

31 31 Source and destination port adresses are the applications access points,. TCP identify an application with its dedicated port number SERVICES DEDICATED PORTS A.Obaid-Wilfried Probst – Rufin Soh INE4481 DISTRIBUTED DATABASES & CLIENT-SERVER ARCHITECTURES


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