lesson 1

According to the end-to-end principle, where should most of the Internet's functionality/intelligence be implemented?

At the edges of a network

How did Licklider and his team in the early 1960s experiment with a precursor to the Internet?

Connecting two computers over a dial-up telephone line

Which of the following protocols belong to the application layer?

DNS (Domain Name Service)

The Spanning Tree Algorithm presented in this lecture always results in a spanning tree that places the root in a topologically central location, so that all the nodes are as "close" as possible to the root.

False. The Spanning Tree Algorithm presented guarantees a unique spanning tree that all the nodes will agree to, but sometimes this isn't the most "optimal" tree possible. Network administrators can configure the switch ID if they want to have a specific spanning tree.

Network traffic cannot traverse an inactive link.

False. Traffic can still reach the link, but the link is not used to forward traffic.

Which of the following are ramifications of the "hourglass shape of the internet"? Applications like BitTorrent leverage peer-to-peer networking instead of a more traditional client-server model for better performance.

False. The hourglass shape of the Internet refers to Internet architecture in terms of protocols available at the different layers.

Both the data link and transports layer protocols may provide error correction.

True

Some data link layer protocols, such 802.11 (WiFi), implement some basic error correction as the physical medium used is easily prone to interference and noise (such as a nearby running microwave). Is this a violation of the end-to-end principle?

No, because violations of the e2e principle typically refer to scenarios where it is not possible to implement a functionality entirely at the end hosts, such as NAT and firewalls. In this question, we have a lower level protocol implementing error checking.

What is the difference between hubs, bridges, and routers?

They operate on different layers of the IP stack

What is the Domain Name System (DNS) designed to do primarily?

Translate domain names into IP addresses

Which of the following are ramifications of the "hourglass shape of the internet"? It has been a difficult and slow process to transition to IPv6, despite the shortage of public IPv4 addresses.

True. A big part of the Internet infrastructure uses IPV4 while the cost of transitioning is high. This reflects as a consequence of the narrow waist.

Which of the following are ramifications of the "hourglass shape of the internet"? Many technologies that were not originally designed for the internet have been modified so that they have versions that can communicate over the internet (such as Radio over IP).

True. Modifying a technology so that it is compatible with the rest of the internet (i.e., by making it compatible with IP) greatly enhances market penetration (from the vendor's perspective), and/or decreases the amount of extra development that would need to happen.

The Spanning Tree Algorithm helps to prevent broadcast storms

True. That is the purpose of the Spanning Tree Algorithm. Although it is still possible to have broadcast storms on the network (such as from a bad network card), STP prevents broadcast storms that result from having loops present in the network topology.

What is the architectural design of the Internet protocol stack based on?

Layers

When an application sends a packet of information across the network, this packet travels down the IP stack and undergoes what process?

Encapsulation

What allows for communication between the application layer and transport layer?

Sockets

Which two protocols belong to the transport layer? Select all that apply.

TCP UDP