2.2-09. HTTP/2 versus HTTP/1.1: object download delays.  Consider a client and a server, separated by an RTT of 4 time units.  The client makes a request for 4 objects at t=0.  O1 consists of 10 frames, O2 and O4 each consist of 1 frame, and O3 consists of 2 frames.  In the HTTP/2 example shown below, the server is transmitting frames to the client in the order  O1, O2, O3, O4 (as long as there are frames of type i to transmit, and when not the server just moves on to a frame from object i+1 mod 4).  Each frame takes 1 time unit to transmit.Under HTTP 1.1 (not shown below), the server would send O1, O2, O3, O4 in that first-come-first-served (FCFS) order, sending each object in its entirety before moving on to send the next object in that order.Let’s define the object download delay as the time from when an object is requested (at t=0 below) to the time that object is received in its entirety.  What is the average object download delay (the sum of the four object download delays divided by 4) under the HTTP/2 object frame transmission order shown below and under HTTP/1.1 O1, O2, O3, O4 object transmission order?Group of answer choicesAverage object download delay under HTTP/1.1: 16.0, under HTTP/2: 10.5Average object download delay under HTTP/1.1: 14.0, under HTTP/2: 9.5Average object download delay under HTTP/1.1: 22.0, under HTTP/2: 17.5Average object download delay under HTTP/1.1: 24.0, under HTTP/2: 18.0Average object download delay under HTTP/1.1: 18.0, under HTTP/2: 14.0Average object download delay under HTTP/1.1: 12.5, under HTTP/2: 10.0

2.2-05. Download delays for 100 objects (HTTP 1.0). Consider an HTTP 1.0 client and server. The RTT delay between the client and server is 2 seconds.  Suppose the time a server needs to transmit an object into its outgoing link is 3 seconds, as shown below for the first of these 100 requests. You can assume that any other HTTP message not containing an object sent by the client and server has a negligible (zero) transmission time. Suppose the client makes 100 requests, one after the other, waiting for a reply to a request before sending the next request.Using HTTP 1.0, how much time elapses between the client transmitting the first request, and the receipt of the last requested object?Group of answer choices300 secs700 secs203 secs502 secs500 secs

2.2-11a. Local Web Caching (a). Consider the following scenario, in which a Web browser (lower) connects to a web server (above).  There is also a local web cache in the bowser’s access network.  In this question, we will ignore browser caching (so make sure you understand the difference between a browser cache and a web cache). Assume that the total Round Trip Time propagation, queueing and object transmission delay between the browser and web server (and including TCP setup time) is 250 msec; if the object is retrieved from the local web cache, this delay is only  10 msec.Suppose that 80 percent of the time when the browser makes a request, the requested object is found in the local web cache.  What is the average time (over all requests that the browser makes to this site) from when the browser issues the initial HTTP GET request until it is able to display the requested object?Group of answer choices250 msec220 msec420 msec230 msec58 msec88 msec120 msec

Problem 1. Web and HTTP Quickies. a) True or false? A user requests a Web page that consists of some text and three images. For this page, the client will send one request message and receive four response messages. Give one or two sentences of explanation. b) True or false? The Date: header in the HTTP response message indicates when the object in the response was last modified. Give one or two sentences of explanation. c) Why do you think the HTTP protocols run on top of TCP rather than on UDP? d) What is an important difference between a web cache, and a browser cache? Your answer need only be a couple of sentences long. There are a number of correct answers here.

Which of he following statements is NOT true concerning streaming of video or audio over the Internet?Question 6AnswerAdaptive streaming requires that there should be multiple encoded versions of the same content available from the serverStreaming is characterised by the need to continuously receive, decode and render (or "play") a segment of the media within a fixed deadlineThe need to accommodate packet delay variation and packet loss can mean a long delay in the receiver due to bufferingProgressive Download requires the whole media file to be downloaded before playback can begin

Answer the following:a. True or false?i. A user requests a Web page that consists of some text and three images. Forthis page, the client will send one request message and receive four responsemessages.ii. Two distinct Web pages (for example, www.mit.edu/research.html andwww.mit.edu/students.html) can be sent over the same persistent connection.iii. With nonpersistent connections between browser and origin server, it ispossible for a single TCP segment to carry two distinct HTTP requestmessages.iv. The Date: header in the HTTP response message indicates when the object inthe response was last modified.v. HTTP response messages never have an empty message body