Computer Networking Chapter 1 Quiz

Introduction to Computer Networking

• The book is titled "Computer Networking: A Top-Down Approach" by Jim Kurose and Keith Ross.
• It's the 6th edition, published by Addison-Wesley in March 2012.
• The authors' intent was to share PowerPoint slides freely with educators, students, and readers.
• Modifications, additions, and deletions are encouraged.
• The ppt slides are adapted, and if they are used or posted online, the source must be credited.

Chapter 1 Roadmap

• 1.1 What is the Internet?
• 1.2 Network Edge: Includes end systems, access networks, and links.
• 1.3 Network Core: Focuses on packet switching, circuit switching, and network structure.
• 1.4 Delay, Loss, Throughput in Networks: Discusses network performance issues.
• 1.5 Protocol Layers, Service Models: Explores protocol layering and service models.
• 1.6 Networks Under Attack: Security: Covers network security.
• 1.7 History: Provides historical context.

What's the Internet: "nuts and bolts" view

• The Internet is a network of networks.
• It consists of interconnected internet service providers (ISPs).
• Communication protocols (e.g., TCP, IP, HTTP) dictate how messages are sent and received.
• Internet standards are defined by RFCs and developed by the IETF.

What's the Internet: "a service view"

• The Internet infrastructure provides services to applications.
• Applications like web, VoIP, email, games, and e-commerce utilize this infrastructure.
• Applications communicate via a programming interface that connects them to the Internet, similar to a postal service.

What's a Protocol?

• Protocols define message formats, transmission order, and actions network entities take upon message transmission and receipt.
• Human protocols (e.g., greetings, questions) are equivalent to computer network protocols.

A Closer Look at Network Structure

• Network Edge: Comprises hosts, clients, and servers.
• Access Networks: Includes physical media such as wired and wireless communication links.
• Network Core: Formed by interconnected routers that work as a network of networks.

Access Networks and Physical Media

• Access networks connect end systems to edge routers.
• Types of access networks include residential, institutional, and mobile networks.
• The relevant physical media include wired, wireless, fiber optic cables, and radio.

Access Networks: DSL

• Digital subscriber line (DSL) uses existing telephone lines.
• Data and voice are sent over different frequencies over the phone line.
• Typical downstream rates are 24 Mbps, while upstream rates are typically < 2.5 Mbps.

Access Networks: Cable

• Cable networks use frequency division multiplexing.
• Cable modems transmit data and TV signals over shared cable lines.
• HFC (Hybrid Fiber Coax) combines fiber and coaxial cable for high-speed transmission.

Access Networks: Home Network

• Home networks combine wireless and wired devices often in a single box.
• Wireless access points, routers, firewalls, and NAT devices help connect to the Internet.
• Wired Ethernet has a 100 Mbps transmission rate.

Access Networks: Enterprise Ethernet

• Ethernet is commonly used in companies and universities.
• Transmission rates vary from 10 Mbps to 10 Gbps.
• Various end systems often connect to Ethernet switches within enterprises.

Wireless Access Networks

• Wireless access networks connect end systems to routers via base stations or access points.
• Wireless LANs often use 802.11 protocols (WiFi).
• Wide-area wireless access uses technologies like 3G, 4G (LTE).

Host: Sends Packets of Data

• A host breaking an application message into smaller packets of data.
• Packet length (L) and link bandwidth (R) determine transmission delay.

Physical Media

• Physical media include twisted-pair, coaxial cable, fiber optic cable, and radio.
• Guided media involves signals traveling along a physical path, while unguided media allows signals to propagate freely in the air.
• Characteristics of each physical medium include speed or capacity and the environment in which they use.

Packet Loss

• Packet loss occurs when buffers in a router are full.
• Packets arrive at a rate exceeding the output link's capacity, leading to dropping packets.

Throughput

• Throughput is the rate at which bits are transferred between a sender and receiver.
• Instantaneous throughput is the rate at a specific point in time, while average throughput is over a longer time period.

Throughput: Internet Scenario

• End-to-end throughput depends on the bottleneck link's capacity and other factors, which are shown in an illustrative diagram.

"Real" Internet Delays and Routes

• Traceroute is a program that measures delays and shows the path packets take through the Internet.
• Traceroute traces a path from source to destination, showing delays at each router.

Test your knowledge on the key concepts from Chapter 1 of 'Computer Networking: A Top-Down Approach'. This chapter covers the Internet's structure, network edge and core, performance issues, protocol layers, security concerns, and a brief history. Perfect for students wanting to solidify their understanding of introductory networking topics.