CSC438 Quiz 1 - computer networking

What percentage of people in the USA use the Internet?

93%

What is the global percentage of people using the Internet?

Over 60%

What are the two main types of switching in network core?

Packet switching and circuit switching

What is the Internet often referred to as?

A network of networks

What are end systems in a network?

Hosts such as PCs, servers, and mobile devices

What is the role of protocols in networking?

govern all communication activity in the Internet

What does TCP stand for?

Transmission Control Protocol

What is the function of a router in a network?

To forward packets (chunks of data) between networks

What is the purpose of the Internet Engineering Task Force (IETF)?

To develop and promote Internet standards

What is a digital subscriber line (DSL)?

A type of access network that transmits data over telephone lines

What is the typical upstream transmission rate for DSL?

Less than 2.5 Mbps

What is the typical downstream transmission rate for DSL?

Less than 24 Mbps

What technology is used in cable networks for data transmission?

Frequency division multiplexing

What is the transmission rate range for fiber optic cables?

10's to 100's Gbps

What are the two types of physical media in networking?

Guided media (e.g., copper, fiber) and unguided media (e.g., radio)

What is the maximum transmission rate for WiFi (802.11ax)?

Up to 11 Gbps

What is the typical end-to-end delay for satellite communication?

Approximately 270 milliseconds

What is the purpose of a cable modem?

To connect a home network to the Internet via a cable network

What is an access point in a wireless network?

A base station that connects end systems to the router

What is the function of a firewall in a home network?

To protect the network from unauthorized access

What is the significance of the Request for Comments (RFC)?

It is a series of memoranda describing methods, behaviors, investigations, or advances related to the operation of the Internet.

What is the typical transmission rate for institutional access networks using Ethernet?

100 Mbps to 10 Gbps

What is the main characteristic of a shared wireless access network?

Multiple users share the same wireless bandwidth

What are the two main types of wireless access networks?

Wide-area wireless access and wireless LANs

What is the role of a DSLAM in a DSL network?

To multiplex multiple DSL connections into a single high-capacity connection

What is the primary function of network protocols?

To define the format, order of messages sent and received, and actions taken on message transmission and receipt.

What is the network core?

A mesh of interconnected routers.

What is packet-switching?

A method where hosts break application-layer messages into packets and forward them from one router to the next.

What does a host do in packet transmission?

It sends packets of data by breaking application messages into smaller chunks, known as packets.

What is link transmission rate?

Also known as link capacity or link bandwidth, it is the rate at which data can be transmitted over a link.

How is transmission delay calculated?

calculated as L (bits) / R (bits/sec), where L is the packet size and R is the link transmission rate.

What is store-and-forward in packet-switching?

A method where the entire packet must arrive at a router before it can be transmitted on the next link.

What are the two key functions of the network core?

Routing and forwarding.

What is routing?

The process that determines the source-destination route taken by packets.

What is forwarding?

The process of moving packets from a router's input to the appropriate router output.

What is circuit switching?

A method where end-end resources are allocated and reserved for a call between source and destination.

What is the difference between FDM and TDM in circuit switching?

FDM allocates different frequencies to users, while TDM allocates different time slots.

What is a major advantage of packet switching over circuit switching?

it allows more users to utilize the network simultaneously.

What is a potential downside of packet switching?

Excessive congestion can lead to packet delay and loss.

What is the Internet structure described as?

A network of networks.

How do end systems connect to the Internet?

Through access ISPs (Internet Service Providers).

What is the problem with connecting each access ISP to every other access ISP?

It doesn't scale due to O(N^2) connections.

What is a global transit ISP?

An ISP that connects multiple access ISPs and has economic agreements with them.

What is an Internet Exchange Point (IXP)?

A physical infrastructure that allows different networks to connect and exchange traffic.

What are regional networks in the context of Internet structure?

Networks that connect access networks to ISPs.

What role do content provider networks play?

They run their own networks to bring services and content closer to end users.

What characterizes Tier 1 ISPs?

They are well-connected large networks with national and international coverage.

What is the purpose of a content provider network like Google?

To connect its data centers to the Internet, often bypassing Tier 1 and regional ISPs.

What is the roadmap for understanding the Internet structure?

1. What is the Internet? 2. Network edge. 3. Network core. 4. Delay, loss, throughput in networks. 5. Protocol layers, service models. 6. Networks under attack: security.

What is the significance of understanding loss and delay in networks?

It helps in diagnosing performance issues and improving network efficiency.

What happens when packet arrival rate exceeds output link capacity?

Packets queue and wait for their turn to be transmitted.

What are the four sources of packet delay?

Nodal processing delay, queueing delay, transmission delay, and propagation delay.

What is nodal processing delay?

The time taken to check bit errors and determine the output link, typically less than a millisecond.

What is queueing delay?

The time a packet spends waiting at the output link for transmission, which depends on the congestion level.

What is propagation delay?

is calculated as d/s, where d is the length of the physical link and s is the propagation speed in the medium.

What does La/R represent in networking?

it represents traffic intensity, indicating the average packet arrival rate relative to link capacity.

What happens when La/R is greater than 1?

It indicates that more work is arriving than can be serviced, leading to infinite average delay.

What is the purpose of the traceroute program?

measures the delay from the source to routers along the end-to-end Internet path towards a destination.

What is packet loss?

occurs when a packet arrives at a full queue and is dropped, potentially leading to retransmission.

What is throughput in networking?

it is the rate at which bits are transferred between sender and receiver, measured in bits per time unit.

What is the difference between instantaneous and average throughput?

Instantaneous throughput is the rate at a given moment, while average throughput is the rate over a longer period.

What is a bottleneck link?

the link on the end-to-end path that constrains the overall throughput.

What is the Internet protocol stack?

application, transport, network, link, and physical.

What is the function of the transport layer in the Internet protocol stack?

its responsible for process-to-process data transfer, using protocols like TCP and UDP.

What does the network layer do?

handles the routing of datagrams from source to destination.

What is the role of the link layer?

responsible for data transfer between neighboring network elements.

What is encapsulation in networking?

the process of wrapping data with protocol information at each layer of the protocol stack.

What are the three major topics in network security?

How attacks occur, how to defend against them, and how to design secure architectures.

What is malware?

malicious software that can infect hosts via viruses, worms, or spyware.

What is a Denial of Service (DoS) attack?

this attack makes resources unavailable to legitimate traffic by overwhelming them with bogus traffic.

What is packet sniffing?

the practice of capturing packets on a network, often to gather sensitive information.

What is IP spoofing?

involves sending packets with a false source address to disguise the sender's identity.

What is the significance of the layered approach in networking?

it allows for modularization, making maintenance and updates easier without affecting the entire system.

What is the role of the application layer in the Internet protocol stack?

supports network applications like FTP, SMTP, and HTTP.

What is the difference between circuit switching and packet switching?

Circuit switching establishes a dedicated path for communication, while packet switching sends data in packets over shared links.

What is the purpose of the ISO/OSI reference model?

it provides a framework for understanding and discussing network protocols and services.

What is the significance of the roadmap in networking?

outlines the key topics in networking, including the Internet structure, performance metrics, and security.