Blog

In the subnet 1.2.3.4/24 represented using the CIDR notation, how  many IP addresses are available?

The figure below illustrates an IPsec configuration in the tunnel mode with the ESP header, in which the IPsec gateways are located at R1 and R2. Answer the following True/False questions, and briefly justify your answers. A. [2 points] When a host in 172.16.1/24 sends a datagram to an Amazon.com server, the router R1 will encrypt the datagram using IPsec. B. [2 points] When a host in 172.16.1/24 sends a datagram to a host in 172.16.2/24, the router R1 will change the source and destination address of the IP datagram. C. [2 points] Consider sending a TCP segment from a host in 172.16.1/24 to a host in 172.16.2/24. Suppose the acknowledgment for this segment gets lost, so that TCP resends the segment. Because IPsec uses sequence numbers, R1 will not resend the TCP segment.  

Let’s consider the operation of a learning switch in the context of a network in which 6 nodes labeled A through F are star connected into an Ethernet switch. Suppose that (i) B sends a frame to E, (ii) E replies with a frame to B, (iii) A sends a frame to B, (iv) B replies with a frame to A. The switch table is initially empty. Show the state of the switch table before and after each of these events. For each of these events, identify the link(s) on which the transmitted frame will be forwarded. Answer by filling in the provided table below. Switch table state Links to forward frame B -> E E -> B A -> B B -> A

What is a potential drawback of field testing compared to laboratory testing?

Using vanilla HTML, CSS, and JS, which of the following creates a div that will take up ⅓ width (~33.3%) of a row on a small device, and ¼  width (25%) of a row on a large device?

Raster graphics are made of mathematically-calculated shapes and lines and therefore can be scaled up without losing quality.

A Pressable component allows a function to be defined for both the “press” and “long press” gestures.

Which of the following is the correct way to respond to the user’s request of GET /health with a successful status and a message body of “hello world!”? // (A)app.get(‘/health’, (req, res) => {     return “hello world”;});   // (B)app.get(‘/health’, (req, res) => {     return {        status: 200,        msg: “hello world”     };});   // (C)app.get(‘/health’, (req, res) => {     res.status(200).send(“hello world”);});   // (D)app.get(‘/health’, (req, res) => {     res.status(400).send(“hello world”);});

What are the three components of a three-dimensional model of prototyping?

Consider the following React Native component… function Fader() {  const fadeAnim = useRef(new Animated.Value(1));  function fade() {    Animated.timing(fadeAnim.current, {      toValue: 0,      duration: 10000,      useNativeDriver: true,    }).start();  }  return      } What will happen when the “Press Me” button is pressed?