Networks and Protocols Communication Architecture and Network Protocol

Networks and Protocols Communication Architecture and Network Protocol Layering Prepared by: TGK First Prepared on: Last Modified on: Quality checked by: Copyright 2009 Asia Pacific Institute of Information Technology

Topic & Structure of the lesson Communication Architecture and Network Protocol Layering • Introduction to Data Communication Model • Data Communication Networking • Protocols and Protocol Architecture Networks and Protocols 2

Learning Outcomes Communication Architecture and Network Protocol Layering At the end of this module, YOU should be able to: • Explain the Networking deals with the technology and architecture. • Explain the communication protocols in Computer Networks and Protocols 3

Key Terms you must be able to use Communication Architecture and Network Protocol Layering If you have mastered this topic, you should be able to use the following terms correctly in your assignments and exams: • • Networking Entity System Protocol Syntax Semantics PDU Networks and Protocols 4

Main Teaching Points Communication Architecture and Network Protocol Layering • Data Communications Model • Networking • Wide Area Networks • Local Area Networks • Protocols • OSI Reference Model • TCP/IP Protocol Suite Networks and Protocols 5

Data Communications Model Communication Architecture and Network Protocol Layering n Source: generates data to be transmitted n Transmitter: converts data into signals n Transmission System: carries the signals n Receiver: converts received signal into data n Destination: takes incoming data Networks and Protocols 6

Data Communications Reference Model Communication Architecture and Network Protocol Layering Figure 1. 1 Simplified Communication Model – William Stalling Data and Computer communication Networks and Protocols 7

Networking Communication Architecture and Network Protocol Layering Point to Point communication not practical n Devices are too far apart n Large set of devices would need n impractical number of connections n Solution is a communications network Networks and Protocols 8

Networking Communication Architecture and Network Protocol Layering Figure 1. 3 Simplified Network Model – William Stalling- Data and Computer communication Networks and Protocols 9

Wide Area Network Communication Architecture and Network Protocol Layering • • Large geographical area Crossing public rights of way Rely in part on common carrier circuits Alternative technologies – Circuit switching – Packet switching – Frame relay – Asynchronous Transfer Mode (ATM) Networks and Protocols 10

Local Area Network Communication Architecture and Network Protocol Layering Smaller scope – Building or small campus • Usually owned by same organization as attached devices • Data rates much higher than WAN • Usually broadcast systems • Now some switched systems and ATM are being introduced Networks and Protocols 11

Protocols Communication Architecture and Network Protocol Layering • ENTITY - anything capable of sending or receiving info: – application program – file transfer package – e-mail package • SYSTEM - a physically distinct object that contains one or more ENTITIES: – computer, terminals, remote sensors etc. Networks and Protocols 12

Protocols Communication Architecture and Network Protocol Layering For two entities to successfully communicate, they must agree on: • What is communicated? • How is it communicated? • When is it communicated? • Must conform to some mutually acceptable set of conventions governing the exchange of data between the entities: PROTOCOLS Networks and Protocols 13

Protocols Communication Architecture and Network Protocol Layering Key Elements of Protocols • Syntax – Data formats, Signal levels • Semantics – Control information, Error handling • Timing – Speed matching, Sequencing Networks and Protocols 14

Protocol Architecture Communication Architecture and Network Protocol Layering • Task of communication is broken up into modules • For example file transfer could use three modules – File transfer application – Communication service module – Network access module Networks and Protocols 15

Protocol Architecture Communication Architecture and Network Protocol Layering Overview of Networking Simplified File Transfer Architecture Figure 1. 6 Protocol in Simplified Architecture – William Stalling – D&C Communication Networks and Protocols 16

Protocol Architecture Communication Architecture and Network Protocol Layering Addressing Requirements • Two levels of addressing required • Each computer needs unique network address • Each application on a (multi-tasking) computer needs a unique address within the computer – The service access point or SAP Networks and Protocols 17

Protocol Architecture Communication Architecture and Network Protocol Layering Protocol Data Unit (PDU) • • At each layer, protocols are used to communicate Control information is added to user data at each layer Transport layer may fragment user data Each fragment has a transport header added – Destination SAP – Sequence number – Error detection code • This gives a transport protocol data unit Networks and Protocols 18

OSI Reference Model Communication Architecture and Network Protocol Layering • A layer model • Each layer performs a subset of the required communication functions • Each layer relies on the next lower layer to perform more primitive functions • Each layer provides services to the next higher layer • Changes in one layer should not require changes in other layers Networks and Protocols 19

TCP/IP Protocol Suite Communication Architecture and Network Protocol Layering • • Dominant commercial protocol architecture Specified and extensively used before OSI Developed by research funded US Department of Defense Used by the Internet Networks and Protocols 20

TCP/IP Protocol Suite Communication Architecture and Network Protocol Layering TCP/IP Protocol Architecture • Application Layer – Communication between processes or applications • End to end or transport layer (TCP/UDP/…) – End to end transfer of data – May include reliability mechanism (TCP) – Hides detail of underlying network • Internet Layer (IP) – Routing of data Networks and Protocols 21

TCP/IP Protocol Suite Communication Architecture and Network Protocol Layering Network Layer – Logical interface between end system and network • Physical Layer – Transmission medium – Signal rate and encoding Networks and Protocols 22

Quick Review Question Communication Architecture and Network Protocol Layering 1. List the major disadvantages with the layered approach to protocols. 2. Discuss the need or lack of need for a network layer(OSI layer 3) in a broadcast network. Networks and Protocols 23

Follow Up Assignment Communication Architecture and Network Protocol Layering Presentation on Layered Model Approach (OSI or TCP/IP) Networks and Protocols 24

Summary of Main Teaching Points Communication Architecture and Network Protocol Layering • • • Data Communications Model Networking Wide Area Networks Local Area Networks Protocols Key Elements of Protocols Protocol Architecture Addressing Requirements Protocol Data Unit (PDU) • OSI Reference Model • TCP/IP Protocol Suite Networks and Protocols 25

Question and Answer Session Communication Architecture and Network Protocol Layering Q&A Networks and Protocols 26

Next Session Communication Architecture and Network Protocol Layering Topic and Structure of next session § Network Hardware (I) n n Networks and Protocols Classification of Networks (PAN, LAN, MAN, and WAN) WAN technologies (Frame Relay, ISDN, and ATM) 27