CPE401_MODULE2B_Data_Communication_and_Networking.pdf
- 1. CPE401 Data Communications & Computer Networks Prof. A. I. Oluwaranti niranoluwaranti@oauife.edu.ng Slides developed from Data Communications and Networking. Forth Edition. By Behrouz A. Forouzan and other online materials Module 2b:
- 2. • Responsible of: • Moving frames from one hop (node) to the next. • Framing: divided the stream of bits received from the network layer manageable data units called frames. • Physical address (MAC address). • Flow control. • Error control: added trailer to the end of frame. • Access control. • Hop to hop delivery Layer 2: Data Link layer
- 3. a) Error control to compensate for the imperfections of the physical layer. b) Flow control to keep a fast sender from swamping a slow receiver. • Main topics: • Framing methods • Error detection and correction methods • Flow control • Frame format • IEEE LAN standards • Bridges • Switches (multi-port bridges) Data Link layer contd.
- 4. Data Link layer contd. 10110110101 01100010011 10110000001
- 6. • The network layer is responsible: • The delivery of individual packets from the original source to the final destination • Logical addressing: if the packet passes the network boundary there is a need for another addressing system to help (source to destination) connection. • Routing: route or switch the packet to final destination. • Source-to-destination delivery (End-to-End). Layer 3: Network Layer
- 7. a) Controls the operation of the subnet. b) Routing packets from source to destination. c) Logical addressing. • Main topics: • Internetworking • Routing algorithms • Internet Protocol (IP) addressing • Routers Network Layer contd.
- 10. • The transport layer is responsible for: • Service point or Port addressing • Segmentation and reassembly : § a message is divided into transmittable segments each segment containing a sequence no. • Connection Control: connection oriented or connectionless. • Flow control • Error control Layer 4: Transport Layer
- 11. a) Provides additional Quality of Service. b) Heart of the OSI model. • Main topics: • Connection-oriented and connectionless services • Transmission Control Protocol (TCP) • User Datagram Protocol (UDP) Layer 4: Transport Layer contd.
- 13. Reliable process-to-process delivery of a message
- 14. • Dialogue control: design to establish, maintain, and synchronize the interaction between communicating systems. • Synchronization: it allows a process to add checkpoints or synchronization points to a data stream. Layer 5: Session Layer
- 16. • Design to the handle the syntax and semantic of the information exchanged between 2 systems. • Design for: • data translation • encryption • decryption • compression. • Where is data compression required? Layer 6 :Presentation Layer
- 18. Layer 7: Application Layer The application layer is responsible for providing services to the user. Mail services File transfer, access and management Remote log-in or network virtual terminal Accessing the World Wide Web Directory service
- 19. a) Provides protocols that are commonly needed. • Main topics: • File Transfer Protocol (FTP) • HyperText Transfer Protocol (HTTP) • Simple Mail Transfer Protocol (SMTP) • Simple Network Management Protocol (SNMP) • Network File System (NFS) • Telnet Application Layer (contd)
- 21. data data data data Network header data Frame H Network H data Segments packets Frames Bits From trailer data stream data stream data stream Application Presentation Session Transport Network Data link Physical 1110111 0111 011111101
- 22. Summary
- 23. •The TCP/IP protocol suite is a hierarchical protocol , made of five layers: • Application layer • Transport layer • Network layer • Data link layer • Physical layer TCP/IP Protocol Suite
- 24. • The layers in the TCP/IP protocol suite do not exactly match those in the OSI model. • The original TCP/IP protocol suite was defined as having four layers: host-to-network, internet, transport, and application. • However, when TCP/IP is compared to OSI, we can say that the TCP/IP protocol suite is made of five layers: physical, data link, network, transport, and application. TCP/IP PROTOCOL SUITE
- 25. TCP/IP and OSI model
- 26. • Four levels of addresses are used in an internet employing the TCP/IP protocols: • physical address • logical address • port address • specific address ADDRESSING
- 27. Relationship of layers and addresses in TCP/IP SCTP: Stream Control Transmission Protocol TCP: Transmission Control Protocol UDP: User Datagram Protocol
- 28. • Physical address, also known as the link address, is the address of a node as defined by its LAN or WAN. • It is included in the frame used by the data link layer. It is the lowest- level address • The size and format of these addresses vary depending on the network. E.g., Ethernet uses a 6- byte (48-bit) physical address that is imprinted on the NIC Physical Address
- 29. • In Figure below, a node with physical address 10 sends a frame to a node with physical address 87. The two nodes are connected by a link (bus topology LAN). As the figure shows, the computer with physical address 10 is the sender, and the computer with physical address 87 is the receiver. Example 1
- 30. • Figure 2 shows a part of an internet with two routers connecting three LANs. Each device (computer or router) has a pair of addresses (logical and physical) for each connection. • In this case, each computer is connected to only one link and therefore has only one pair of addresses. Each router, however, is connected to three networks (only two are shown in the figure). • So each router has three pairs of addresses, one for each connection. Example 2
- 31. Figure 2. IP addresses
- 32. • Figure 3 shows two computers communicating via the Internet. • The sending computer is running three processes at this time with port addresses a, b, and c. • The receiving computer is running two processes at this time with port addresses j and k. • Process a in the sending computer needs to communicate with process j in the receiving computer. • Note that although physical addresses change from hop to hop, logical and port addresses remain the same from the source to destination. Example 3
- 33. Figure 3 Port addresses
- 34. OSI and Protocol Stack OSI Model TCP/IP Hierarchy Protocols 7th Application Layer 6th Presentation Layer 5th Session Layer 4th Transport Layer 3rd Network Layer 2nd Link Layer 1st Physical Layer Application Layer Transport Layer Network Layer Link Layer Link Layer : includes device driver and network interface card Network Layer : handles the movement of packets, i.e. Routing Transport Layer : provides a reliable flow of data between two hosts Application Layer : handles the details of the particular application
- 35. Packet Encapsulation n The data is sent down the protocol stack n Each layer adds to the data by prepending headers 22Bytes 20Bytes 20Bytes 4Bytes 64 to 1500 Bytes