Computer Networking Chapter 1 Quiz

Study Notes

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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).

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

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.

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

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.