Data and Computer Communications by William Stallings Eighth Edition

1. Data and Computer Communications by William Stallings Eighth Edition Protocol Architecture, TCP/IP, and Internet-Based Applications Click to edit Master subtitle style Chapter 2 Networks and Communication Department

2. Need For Protocol Architecture • data exchange can involve complex procedures. • better if task broken into subtasks • implemented separately in layers in stack • each layer provides functions needed to perform functions for layers above • using functions provided by layers below • layers communicate using a set of rules known as a protocol.

3. TCP/IP Protocol Architecture • developed by US Defense Advanced Research Project Agency (DARPA) • for ARPANET packet switched network • used by the global Internet

4. 1) TCP/IP Layers 5.Application layer 4.transport layer 3.Network layer 2.Data link layer 1. Physical layer

5. Physical Layer • The physical layer is responsible transforming data into bits. • concerned with issues like: • characteristics of transmission medium • Representation of bits and signal levels: how 0,1 are changed to signals. • data rates: number of bits sent per second and duration of bits. • Synchronization of bits.

6. Data link Layer • The data link layer is responsible for moving frames from one hop(node)to the next • It adds a header to the frame to define the sender and the receiver of the frame. • Using physical address(MAC) : the local address of a node as defined by its LAN pr WAN. • concerned with issues like: • -Flow control • -Error control

8. Data link Layer • The data link layer is responsible for moving frames from one hop(node)to the next

9. Hop-to-hop delivery

10. Network layer • Network layer is responsible for the delivery of packets from the source host to the destination host across multiple networks. • using IP address: 32-bit address that uniquely define a host connected to the internet. • routers connect two networks and relays data between them

11. Source-to-destination delivery

13. Transport Layer (TCP) • Delivery from a specific process on a computer to specific process on the other • Using Port address: 16-bit address to choose among multiple processes on the destination host.

14. Process-to-process delivery

15. Application Layer • Enables the user to access the network

16. Addressing Requirements • Three levels of addressing required: • each host on a subnet needs a unique global network address its IP address • each application on a (multi-tasking) host needs a unique address within the host known as a port address • Physical address

18. 2) OSI • Open Systems Interconnection • developed by the International Organization for Standardization (ISO) • has seven layers

19. OSI Model

20. Session layer • The session layer is responsible for dialog control and synchronization . • Establish, manage ,terminate session

21. Presentation layer • The presentation layer is concerned with the syntax and semantics of the information exchanged between two systems

22. Summary of layers