Ne Network M k Mode dels ls and and Pr Protoco col Suites 01204325 Data Communications and Computer Networks Chaiporn Ja Chaipo Jaikaeo De Department of f Computer Engineering Kasetsart Unive versity Based on lecture materials from Data Communications and Networking, 5 th ed., Behrouz A. Forouzan, McGraw Hill, 2012. Revised 2020-07-15
Out Outline line • Communication abstraction • Layered tasks • Internet protocol suites • ISO's OSI model 2
Real-Li Re Life Example • Communication takes place thru many entities Logical communication Secretary: Secretary: reads and reports types a letter the message Delivery boy: Delivery boy: drops the letter takes the letter Postal truck Post office: Processes and routes the letter 3
Com Communicati tion on Abstr tracti tion on Application-to-application communication A B application application process process 4
Com Communicati tion on Abstr tracti tion on End-to-end data transport over the Internet Internet A B Transport service 5
Com Communicati tion on Abstr tracti tion on Data routing service over the Internet router 6
Com Communicati tion on Abstr tracti tion on Node-to-node delivery link link link 7
Com Communicati tion on Abstr tracti tion on Signal transmitted over physical media Point-to-point link (optical fiber, copper, etc ) NIC ( N etwork I nterface C ard) Multipoint Wireless Image by OpenClipArt-Vectors from Pixabay 8
In Inter ernet Layer er Model el • The Internet Protocol Stack User Application Layer Software Transport Layer Network Layer Data Link Layer Physical Layer Hardware Transmission Medium 9
Ap Application Layer A B Responsible for provi viding servi vices to the user application • The only layer to interact with users (source) (destination) Msg Msg Logical communication Application SMTP HTTP FTP SMTP HTTP FTP Layer Msg H5 Msg H5 Transport Layer 10
Tr Transport Layer Responsible for delive very of a message fr from one process to another • Duties/services ◦ Port addressing ◦ Segmentation and reassembly ◦ Connection control ◦ Flow control (end-to-end) ◦ Error control (end-to-end) 11
Tr Transport Layer (source) (destination) … … Process Process Process Process PORT # PORT # Data Data Transport Data 1 H4 Data 2 H4 Data 3 H4 Data 1 H4 Data 2 H4 Data 3 H4 Layer (segments) Network Layer 12
Ne Network L k Layer Responsible for the delive very of packets fr from the original source to the destination • Duties/services ◦ Logical addressing ◦ Routing 13
Ne Network L k Layer (source) (destination) from Transport to Transport Segment Segment router router Segment H3 Segment H3 Segment H3 Segment H3 (packet) Data Link Layer Data Link Layer Data Link Layer decide which outgoing interface to use 14
Ne Network L k Layer Ope Operatio ion From transport layer Segment A1 C7 A.1, A.2, B.1, B.3, ... are logical addresses A.1 A.2 Network A A.5 Segment A1 C7 R1 B.1 B.7 Network B B.6 B.3 Segment A1 C7 B.9 B.2 R3 R2 C.2 C.3 D.1 Router D.3 Network C C.7 Segment A1 C7 Network D To transport layer D.8 15
Da Data Link Layer Re Responsible for transmitting frames fr from one node to the next • Duties/services ◦ Framing link ◦ Physical addressing ◦ Flow control (hop-to-hop) ◦ Error control (hop-to-hop) ◦ Access control 16
Da Data Link Layer from Network to Network Packet Packet Data Link T2 Packet H2 T2 Packet H2 Layer (frame) Physical Layer 17
Data Link Layer Da 9F 9F, 3B , 3B, 82, 82, 6D 6D, . ... are are ph physical al addre addresses Packet 9F 3B 82 6D T2 Packet 9F 6D H2 18
Da Data Link Layer r Operati tion on Sgmt A.1 C.7 A.1 A.2 97 32 Network A A.5 25 Sgmt A.1 C.7 97 25 R1 B.1 B.7 79 Network B Sgmt A.1 C.7 79 62 B.6 B.3 B.9 62 12 B.2 R3 R2 C.2 C.3 54 88 D.1 D.3 Sgmt A.1 C.7 54 74 Network C C.7 74 Network D Sgmt A.1 C.7 54 74 D.8 To network layer 19
Ph Physic ical L al Layer er Responsible for transmitting indivi vidual bits fr from one node to the next • Duties/services ◦ Physical characteristics of interfaces and media ◦ Representation of bits ◦ Data rate (transmission rate) ◦ Synchronization of bits 20
Ph Physic ical L al Layer er from Data Link to Data Link Frame Frame 01001011 01001011 (bits) Transmission medium 21
The B The Big P g Pict ctur ure L5 data H5 5 5 L5 data H5 L4 data H4 4 4 L4 data H4 L3 data H3 3 3 L3 data H3 T2 L2 data H2 2 2 T2 L2 data H2 0111011010101001010101001 1 1 0111010101010010101010101 Transmission medium 22
Da Data Mo Movement t th thru ru Layers router source router destination Application Application Transport Transport Network Network Network Network Data Link Data Link D.L. D.L. D.L. D.L. Physical Physical P.L. P.L. P.L. P.L. Transmission medium 25
Pr Protoco col Suites • A set of protocols must be constructed ◦ to ensure that the resulting communication system is complete and efficient • Each protocol should handle a part of communication not handled by other protocols • How can we guarantee that protocols work well together? ◦ Instead of creating each protocol in isolation, protocols are designed in complete, cooperative sets called suites or families 26
Inter In ernet Protocol l Suit ite Layer Protocols Application HTTP, FTP, Telnet, SMTP, ... Transport TCP, UDP, SCTP, ... Network IP (IPv4), IPv6, ICMP, IGMP, ... Data Link Ethernet, Wi-Fi, PPP, ... Physical RS-232, DSL, 10Base-T, ... 27
OSI Model OSI M del User • OSI – O pen S ystems I nterconnection 7.Application Layer • Developed by the I nternational S tandards O rganizations (ISO) 6.Presentation Layer 5.Session Layer 4.Transport Layer • Two additional layers 3.Network Layer ◦ Presentation layer 2.Data Link Layer ◦ Session layer 1.Physical Layer Transmission Medium 28
Se Session L n Layer Re Responsible for establishing, managing and te terminating connections between applications • Duties/services ◦ Interaction management ð Simplex, half-duplex, full-duplex ◦ Session recovery 29
Present Pr ntat ation Layer Responsible for handling differences in Re dat data r a repr presentat atio ion t n to applic applicat atio ions ns • Duties/services ◦ Data translation ◦ Encryption ◦ Decryption ◦ Compression 30
Summa Summary • Layered tasks are used for abstracting complex communication details • Layer models were created for reference ◦Internet model (5 layers) ◦ISO's OSI model (7 layers) • Protocol suite is a collection of protocols operating at various layers 31
De Demon onstr trati tion on router web server router PC Application Application Capture data at this point Transport Transport Network Network Network Network Data Link Data Link D.L. D.L. D.L. D.L. Physical Physical P.L. P.L. P.L. P.L. Transmission medium 32
Recommend
More recommend
