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Questions and Answers

Which of the following is a key concept in the Internet architecture?

Centralized control

Internal changes required to interconnect networks

Guaranteed service model

Minimalism and autonomy (correct)

What is the main purpose of packet switching in the Internet?

To interconnect networks (correct)

To establish dedicated connections

To ensure centralized control

To provide guaranteed service

Which protocol was the first host-host protocol used in the ARPAnet?

ALOHAnet

Ethernet

TCP/IP

NCP (correct)

What is the concept of network of networks in the Internet?

A hierarchy of networks Signup and view all the answers

Which type of switching is used in the Internet to send data packets?

Packet switching Signup and view all the answers

What is the role of routers in the Internet architecture?

To forward packets Signup and view all the answers

Which access technology is used to connect end systems to the Internet?

Ethernet Signup and view all the answers

What are the two main types of physical media used in the Internet?

Copper and fiber optic Signup and view all the answers

What is the term used to describe the delay experienced by packets in a network?

Queuing delay Signup and view all the answers

What are the protocol layers used in the Internet architecture?

Physical, data link, network, transport, application Signup and view all the answers

What are the two main types of switching used in the Internet to send data packets?

Packet switching and circuit switching Signup and view all the answers

What is the main purpose of packet switching in the Internet?

To divide data into packets and send them independently across the network Signup and view all the answers

What are the protocol layers used in the Internet architecture?

TCP/IP layers Signup and view all the answers

What is the concept of network of networks in the Internet?

The interconnection of multiple networks to form a larger network Signup and view all the answers

Which access technology is used to connect end systems to the Internet?

Various types of access technologies such as DSL, cable, and wireless Signup and view all the answers

Study Notes

Network Structure and Protocols

Network Edge: consists of end systems, access networks, and links.
Network Core: consists of packet switching, circuit switching, and network structure.

Access Networks

Digital Subscriber Line (DSL):
- Uses existing telephone line to connect to central office.
- Data transmission rate: upstream (typically < 1 Mbps), downstream (typically < 10 Mbps).
Cable Network:
- Uses hybrid fiber coax (HFC) to connect homes to ISP router.
- Data transmission rate: up to 30 Mbps downstream, 2 Mbps upstream.

Network Core Functions

Routing: determines the source-destination route taken by packets.
Forwarding: moves packets from router's input to appropriate router output.

Packet Switching vs. Circuit Switching

Packet Switching:
- Allows multiple users to share network resources.
- More efficient for bursty data.
- Requires protocols for reliable data transfer and congestion control.
Circuit Switching:
- Provides dedicated resources for a single connection.
- Requires call setup and teardown.

Internet Structure

Network of Networks: interconnected access ISPs, regional ISPs, and network core.
Complexity: driven by economics and national policies.

Protocol Layers

5-Layer Internet Protocol Stack:
- Application layer: supports network applications.
- Transport layer: process-process data transfer.
- Network layer: routing of datagrams.
- Link layer: data transfer between neighboring network elements.
- Physical layer: bits "on the wire".
ISO/OSI Reference Model:
- 7-layered model with additional presentation and session layers.

Network Security

Field of Network Security: focuses on network attacks, defense, and design of secure architectures.
Security Considerations: in all protocol layers.
Threats:
- Malware: viruses, worms, spyware.
- Botnets: infected hosts used for spam and DDoS attacks.### Internet Basics
The Internet consists of end systems, access networks, and links at its edge, and packet switching, circuit switching, and network structure at its core.

Internet History (1961-1972)

1961: Leonard Kleinrock's queueing theory demonstrates the effectiveness of packet switching.
1964: Paul Baran introduces packet switching in military networks.
1967: ARPAnet is conceived by the Advanced Research Projects Agency.
1969: The first ARPAnet node becomes operational.
1972: The public demonstration of ARPAnet takes place, with NCP (Network Control Protocol) as the first host-host protocol, and the first email program is developed.

Internet History (1972-1980)

1970: ALOHAnet, a satellite network, is established in Hawaii.
1974: Vint Cerf and Bob Kahn develop an architecture for interconnecting networks.
1976: Ethernet is developed at Xerox PARC.
Late 1970s: Proprietary architectures such as DECnet, SNA, and XNA emerge.
Late 1970s: Switching fixed-length packets (an ATM precursor) begins.
1979: ARPAnet has 200 nodes.
Cerf and Kahn's internetworking principles include:
- Minimalism and autonomy: no internal changes are required to interconnect networks.
- Best-effort service model.
- Stateless routers.
- Decentralized control, defining today's Internet architecture.

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Description

Quiz: Understanding Queueing Delay and Throughput in Internet Scenarios Test your knowledge on queueing delay and throughput in Internet scenarios with this quiz. Learn about the impact of La/R ratios on queueing delay, the concept of bottleneck links, and how to calculate per-connection endend throughput. Sharpen your understanding of these key concepts in networking.