McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Overview of Data Communications and Networking PART I

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Overview

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Chapters Chapter 1 Introduction Chapter 2 Network Models

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Chapter 1 Introduction

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz 1.1 Data Communication Data communication is the transfer of data from one device to another via some form of transmission medium. A data communications system must transmit data to the correct destination in an accurate and timely manner. Components Data Representation Direction of Data Flow

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.1 Five components of data communication are the message, sender, receiver, medium, and protocol.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Data Representation text, numbers, images, audio, and video are different forms of information.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.2 Simplex e.g. the keyboard and the monitor Direction of Data Flow

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.3 Half-duplex e.g. Walkie-talkies, CB radios

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.4 Full-duplex e.g. 2 people are communicating by a tel. line

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz A network is a set of communication devices connected by media links. 1.2 Networks

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz 1.2 Networks 1.Distributed Processing Task is divided 2.Network Criteria Important: performance, reliability, security 3.Physical Structures 4.Categories of Networks

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.5 Point-to-point connection Physical Structures 3. Physical Structures In a point-to-point connection, two and only two devices are connected by a dedicated link.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.6 Multipoint connection (timeshare connection – capacity) In a multipoint connection, three or more devices share a link.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz 1.2 NETWORKS How do we categorize? Topology, geography Technology Geographic Wide area networks Metropolitan networks Local area networks Personal networks Technologies Circuit switched Packet switched

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.7 Categories of topology (a network is layout physically) A topology is the geometric representation of the relationship of all the links and linking devices 4. Categories of Networks

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.8 Fully connected mesh topology (for five devices) Every device has a dedicated point to point link to every other device

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.9 Star topology Each device has a dedicated point to point link only to a central controller, called a hub If one device wants to send data to another. It sends the data to the controller, which then relays the data to the other connected device.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.10 Bus topology is multipoint, previous all were point to point connector connection One long cable acts as a backbone

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.11 Ring topology Each device has a dedicated point to point link only with 2 devices on either side of it. When a device receives a signal intended for another device, its repeater regenerates the bits and passes them along.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.12 Categories of networks A network falls is determined by criteria: 1.Its size 2.Its ownership 3.The distance

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.13 LAN - Local Area Network Designed for a single office, campus, building or between nearby buildings. LANs allow resources to be shared Hardware Software Data between PCs or workstations. License restriction

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.13 LAN (Continued) A given LAN use only one type of transmission medium. Speed : 4-16 Mbps Today: 100 Mbps

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.14 MAN Metropolitan Area Network (e.g. cable TV) Designed to extend over an entire city, connects LANs LANs can be shared - offices can be connected via a city

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.15 WAN - Wide Area Network Provides all transmission (data, video, image etc.) over large areas e.g. states, countries, a continent, or the whole world. In contrast to LANs may utilize public, leased, or private communication equipment.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz EO - End Office PSTN – Public Switching Telephony Network PBX – Private Exchange Switch

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz 1.3 The Internet A Brief History The Internet Today When 2 or more networks are connected, they become an internetwork, or internet. An internet is a network of networks. The Internet (upper case) is a collaboration of more than 100s thousands interconnected networks. The Internet is a structured, organized collection of many separate networks. TCP/IP is the protocol suite for the Internet.

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.16 Internet today NAP = Network Access Point is the complex switching stations. Speed: up to 600 Mbps End users to be connected use the services of Internet Service Provider (ISP) There are local, regional, national, and international Internet service providers (ISPs).

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Figure 1.16 Internet today NAP = Network Access Point Up to 600 Mbps

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz 1.4 Protocols and Standards Protocols Set of rules that governs data communication Key elements: Syntax Structure or format – order in which they are presented Semantics Meaning of each section of bits Timing What data and how fast they can be sent

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz A standard provides a model for development that enables a product to work regardless of the individual manufacturer Standards are essential in: i. Creating competitive markets for equipment manufacturers ii. Guaranteeing national and international interoperability and compatibility 1.4 Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz De Facto (by fact) standards Proprietary Nonproprietary De Jure (by law) standards 1.4 Standards Categories

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Standards Organizations The ISO, ITU-T (previously CCITT), ANSI, IEEE, and EIA are some of the organizations involved in standards creation. 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Forum Consist of representatives from interested corporations Present their conclusions to the standards bodies Facilitate standardization process Frame Relay Forum ATM Forum and Consortium Internet Society (ISOC) and Internet Engineering Task Force (IETF) 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Forum are special-interest groups (work with universities and users), that evaluate and standardize new technologies. Internet Standards A Request for Comment (RFC) is an idea or concept that is a precursor to an Internet standard. 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz ISO (International Standards Organization) 1946 – vast number of subjects 89 countries standards ISO is a member of ITU-T Documents are: Draft Draft International International Standard ANSI (American National Standards Institute) Private, nongovernmental, nonprofit organization NIST (National Institute of Standards and Technology) – a part of the US Dept of Commerce IEEE (Institute of Electrical and Electronics Engineering) Largest professional organization in the world ITU-T International Telecommunications Union - Telecommunications Standardization Sector (former CCITT) – 3000 recommendations 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz ISO ISO 8877—Interface in Integrated Services Digital Network (ISDN) ISO 3309—HDLC frame structure ISO 8028—X.25 packet level protocol 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz ITU-T V.32: Defines data transmission over phone lines X.25: Defines transmission over public digital networks I.430: Define physical layer specifications for an interface 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz ANSI X Programming language COBOL SONET Synchronous Optical Network ISDN Integrated Services Digital Network 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz IEEE IEEE 802.3: CSMA/CD LAN IEEE 802.4: Token Bus LAN IEEE 802.5: Token Ring LAN 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz EIA EIA-232: A 25-pin interface standard EIA-449: Specifies a 37-pin connector and a 9-pin connector EIA-530: Defines a 25-pin connector 1.4 Protocols and Standards

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz Federal Communication Commission (FCC) Authority for interstate and international traffic Reviews communication services and prices Reviews technical specs of communication hardware Assigns carrier frequencies for radio and television Public Utility Commission Authority for intrastate traffic 1.4 Regulatory Agencies

McGraw-Hill©The McGraw-Hill Companies, Inc., 2004 expanded by Jozef Goetz