8/28/ Network Models - Lin 1 CPET/ECET Network Models Data Communications and Networking Fall 2004 Professor Paul I-Hai Lin Electrical and Computer Engineering Technology Indiana University-Purdue University Fort Wayne 8/28/ Network Models - Lin Layered Tasks Sender, Receiver, and Carrier Hierarchy Preparation Sending Delivering Services Higher layer uses lower layer service 8/28/ Network Models - Lin Internet Model 5 Layer Model Layer 5 Application Layer 4 Transport Layer 3 Network Layer 2 Data Link Layer 1 Physical 8/28/ Network Models - Lin 4 Peer-to-Peer Processes From Figure 2.3 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 5 Interfaces between Layers Passing data and network info (down/up) Provide modularity to a network Isolate requiring changes to the surrounding layers 8/28/ Network Models - Lin 6 Organization of the Layers Network Support Layers (physical aspects) Electrical specifications Physical connections Physical addressing Transport timing Reliability Layers Layer 1 Physical Layer Layer 2 Data Link Layer Layer 3 Network layer 8/28/ Network Models - Lin 7 Organization of the Layers (cont.) Transport Layer (65536 ports) Layer 4 TCP Transmission Control User Datagram Protocol User Support Layer Layer 5 Applications File Transport Protocol HTTP 8/28/ Network Models - Lin 8 An Exchange Using Internet Model From Figure 2.4 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 9 Physical Layer Data in the Bit Stream Data Rate Synchronization of Bits Interface & Transmission Media Electrical Specification Mechanical Specification Functions and Procedures for data transmission 8/28/ Network Models - Lin 10 Physical Layer From Figure 2.5 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 11 Data Link Layer A Reliable Link Error free to the upper layer (network layer) Major Tasks Framing Physical addressing Flow control Error control Access control 8/28/ Network Models - Lin 12 Data Link Layer (cont.) From Figure 2.6 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 13 Data Link Layer Node-to-Node Delivery From Figure 2.7 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 14 Example 2-1: Data frame Physical addresses Sender node physical address 10 Receiver node Physical address 87 Data Trailer extra bits for error detection 8/28/ Network Models - Lin 15 Example 2-1 Data Frame (cont.) From Figure 2.8 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 16 Network Layer Source to destination delivery of a data packet across multiple networks Upper layer - Transport layer Lower layer Data link layer Logical addressing (IP) Routing 8/28/ Network Models - Lin 17 Network Layer From Figure 2.9 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 18 Network Layer Source-to- Destination Delivery From Figure 2.10 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 19 Example 2-2 Sender (on one LAN) Network address A Physical address 10 Receiver (on another LAN) Network address P Physical address 95 Router 8/28/ Network Models - Lin 20 Example 2-2 From Figure 2.11 of Data Communications and Networking by Forouzan, 3rd T2 Data A P T2 Data A P T2 Data A P 66 95 8/28/ Network Models - Lin 21 Transport Layer Responsible for process-to-process delivery of the entire message Ensure reliable and orderly of data transporting Oversee error control and flow control 8/28/ Network Models - Lin 22 Transport Layer (cont.) From Figure 2.12 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 23 Transport Layer Major Tasks Port addressing (16-bit, ports) Message segmentation and reassembly Connection control Connection-oriented (TCP) Connection-less (User Datagram Protocol) Flow control Error Control 8/28/ Network Models - Lin 24 Reliable Process-to-Process Delivery From Figure 2.13 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 25 Example 2-3 Transport Layer Communication One message Chopped into two data packets The address of sending process is j The address of receiving process is k 2 data packets travel on different paths and may be out of order Reconstruct the message for layer 5 8/28/ Network Models - Lin 26 Example 2-3 Transport Layer Communication (cont.) From Figure 2.14 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 27 Application Layer Enable software of user to access the network Provide user interface and support of services Examples of services Remote log-in Remote file transfer and access WWW access, and more 8/28/ Network Models - Lin 28 Application Layer (cont.) From Figure 2.15 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 29 Summary of Duties From Figure 2.16 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin OSI Model From Figure 2.17 of Data Communications and Networking by Forouzan, 3rd 8/28/ Network Models - Lin 31 Summary Questions?