NT1210 Introduction to Networking Unit 2: Chapter 2, Introduction to Computer Networking 1

Class Agenda 03/22/16 Learning Objectives Lesson Presentation and Discussion: 2 Hours Discussion on Lab Activities: 2 Hours 30 Minutes Discussion on Assignments. Break Times. 10 Minutes break in every 1 Hour. Announcement: Class Quiz 1 will be held in the next class.

Objectives Define a computer network. Identify the primary needs for computer networks and network applications. Draw the four major physical network topologies: bus, star, ring, and mesh. 3

Computer Networking Use large variety of components that must work together. Move bits from one device to another. Bit: Smallest unit of data, binary 1 or 0. Focuses on copying bits on one device to another. Computing devices include computers, gaming systems, televisions, phones, tablets, GPS navigation systems, watches, etc. 4

An Informal General Definition of a Computer Network Telecom: Short for telephone communications Primarily focuses on role of traditional telephone companies. Datacom: Short for data communications Older synonym for computer networking. 5

Data Communication System 1.#

Network Definition A network is a set of devices connected by communication link to share resources The devices are often referred as node. Node can be a computer, printer or any other devices capable of sending and receiving data. A link can be a cable, air, optical fiber, or any medium which can transport a signal carrying information

Overview of Network Components Figure 1-1 Sample Computer Network

Defining a Network with User Applications Computer Networks: Cloud Representing Hidden Parts of the Network 9

Purpose of a Network It can serve a variety of purposes including: File sharing between two computers Video chatting across different parts of the world Surfing the Web Instant messaging (IM) between computer with IM software installed. E-mail Voice over IP (VoIP) A converged network is one that transports multiple forms of traffic (video, voice, and data)

Network Defined by Geography Local-Area Network (LAN) Wireless-Area Network (WLAN) Wide-Area Network (WAN) Metropolitan-Area Network (MAN) Personal-Area Network (PAN)

Network Defined by Resource Location Yet another way to categorize networks is based on where network resources reside. Network that have all the resources residing in a server are called client –server networks. Network that have their resources on several clients and no server is called a peer-to-peer network

Client-Server Network Figure 1-13 Client-Server Network Example

Figure 1-14 Peer-to-Peer Network Example

Network Defined by Topology 1.#

A bus topology connecting three stations 1.#

A ring topology connecting six stations 1.#

A star Topology

A star topology connecting four stations 1.#

A fully connected mesh topology (five devices) 1.#

A hybrid topology: a star backbone with three bus networks 1.#

Network Criteria Performance Depends on Network Elements Measured in terms of Delay and Throughput Reliability Failure rate of network components Measured in terms of availability/robustness Security Data protection against corruption/loss of data due to: 1.Errors 2. Malicious users

Network Services and Applications Email Wed Browsing File Sharing Printer Sharing Voice Calls And more

Email Electronic Mail: One of oldest networking applications. Sends mail electronically with bits. Write (type) email. Identify (type) sender’s and receiver’s email addresses. Give messages to email service. Email service delivers email to destination email address. 24

Sending Email: Network’s Perspective Email servers (software running on computer in network) must be ready to receive, process, and hold emails for clients using SMTP (Simple Mail Transfer Protocol). To send email: Email application sends mail to outgoing mail server using POP3 (Post Office Protocol, ver. 3). Client must know location of outgoing mail server. To receive mail: Email client must get mail from its incoming mail server also using POP3. Email application must know location of incoming mail server. 25

Sending Email: Network’s Perspective Step 1: Barney sends an email to his outgoing email server. Step 2: Barney’s outgoing email server must know how to find the incoming email server used by Fred – more specifically, the incoming email server used by email address fred@example.com. Step 3: Fred’s incoming email server holds the email for Fred, waiting until he next checks his email. Using Outgoing and Incoming Email Services 26 Figure 2-5

Early Analog Voice Calls Majority of telephone services in USA for first 100 years grew from Bell’s original work and business ventures. Local telephone company (Telco) ran cable to each home. Inside Telco network, lots of other equipment connect to create telephone network. Big Picture View, Two Home Phones and the Telco Figure 2-6

Early Analog Voice Calls To create the call, the Telco creates an electrical circuit all the way from one phone to the other. Once the Telco creates the call by creating an electrical circuit, the two people can talk. Electrical Circuit Between Two Phones to Carry the Voice Call 28 Figure 2-7

Digital Voice Calls The two home phones create an electrical circuit into the Telco, but the analog circuit does not extend from phone-to-phone. Analog to the Phones, Digital in the Telco 29 Figure 2-8

A Deeper Look at One Application: World Wide Web World Wide Web (the Web): Web browser software which allows users access to Web may be single most commonly used application in world. Web works well for learning networking because uses basic client-server model. User sits at computer and uses web browser (Web client). “Client” indicates this software receives some type of service from another device (information from web server). 30

World Wide Web The web browser (client) and web server cooperate so that the web browser can get a copy of the information from a web server. The server organizes information into pages called web pages. The web browser asks the web server for a web page, and the server sends the web page back to the web browser. Web Browser Requesting and Receiving a Web Page from a Web Server 31 Figure 2-12

Web Servers (Hardware and Software) Three Steps: Web Server Sends Web Page into Network 32 Figure 2-18

Lab Activities: Lab Manual Complete lab activities on Chapter 2 Lab 2.1: Connecting Computers Lab 2.2: Network Drivers Lab 2.3: Network Types and Topologies Lab 6.3: WLAN Router Configuration

Unit 2 Assignments Unit 2 Assignment 1: Identifying Network Topologies Unit 2 Assignment 2: Computer Basics Review Details of assignments are uploaded on to the class website. http://obinkyerehclassess.weebly.com

Research Assignment Complete Unit 2 Research Project assignment Unit 2 Research Project 1: Chapter 3 Mind Maps in the text book.

Research Assignment Complete Unit 2 Research Project assignment Unit 2 Research Project 1: Chapter 3 Mind Maps in the text book.