Question

ANSWER NETWORKS QUESTIONS (MCQS AND CALCULATIONS)

QUESTIONS ( 11 - 20)

QUESTION 11

1. 1.     Consider the following excerpt from a simple server side UDP program:

Server.py

from socket import *

sName=’127.0.0.1’

sSocket=socket(AF_INET,SOCK_DGRAM)

sSocket.bind((sName, 12005))

while True:

msg, cAddr =sSocket.recvfrom(2048)

newMsg = msg.decode().lower()

  sSocket.sendto(*********************)

What code could be used to replace the **********’s in line 8?

		newMsg.encode(), cAddr
		newMsg.encode()
		msg.encode(), cAddr
		msg.encode()
		none of the above

1 points   

QUESTION 12

1. For a client to obtain an IP address from the local DNS server, the local DNS server must contact a root DNS server, a top level domain server and an authoritative server where the RTT for these are RTT1=4msec, RTT2 = 5msec and RTT3 = 10msec. The RTT to the local DNS is 1msec. What is the total response time, assuming the IP address is cached in the local DNS server.

		20 msec
		19 msec
		1 msec
		11 msec
		None of the above

1 points   

QUESTION 13

1. In this architecture there is minimal or no reliance on dedicated servers

		Client-server
		P2P
		Network
		Application Layer
		None of the above

1 points   

QUESTION 14

1. HTTP request messages are in ____ format.

		7-bit ASCII
		Binary
		Text
		ASCII
		None of the above

1 points   

QUESTION 15

1. What type of a DNS RR stores the canonical hostname for the alias hostname?

		A
		NS
		CNAME
		MX
		None of the above

1 points   

QUESTION 16

1. Consider the message below: What is the size of the document being returned by the server (in bytes)?

HTTP/1.1 200 OK
Date: Tue, 13 Aug 12:21:39 +0000
Server: Apache/2.2.3 (CentOS)
Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000
ETag:17dc6-a5c-bf716880.
Content-Length: 69763
Keep-Alive: timeout=44, max=71
Connection: Keep-alive
Content-type: image/html

1 points   

QUESTION 17

1. Consider the message below: What is the type of file being sent to the client? HTTP/1 200 OK
   Date: Tue, 13 Aug 12:21:39 +0000
   Server: Apache/2.2.3 (CentOS)
   Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000
   ETag:17dc6-a5c-bf716880.
   Content-Length: 69763
   Keep-Alive: timeout=44, max=71
   Connection: Keep-alive
   Content-type: image/html

1 points   

QUESTION 18

1. Suppose within your Web browser you click on a link to obtain a Web page. The IP address for the associated URL is not cached in your local host, so a DNS lookup is necessary to obtain the IP address. Suppose that four DNS servers are visited before your host receives the IP address from DNS. The first DNS server visited is the local DNS cache, with an RTT delay of RTT0 = 2 msecs. The second, third and fourth DNS servers contacted have RTTs of RTT1 = 19, RTT2 = 17, and RTT3 = 26 msecs, respectively. Assume that the Web page associated with the link contains exactly one object, consisting of a small amount of HTML text. Suppose the RTT between the local host and the Web server containing the object is RTTHTTP = 37 msecs. Assuming zero transmission time for the HTML object, how much time elapses (in seconds) from when the client clicks on the link until the client receives the object?

1 points   

QUESTION 19

1. Consider the message below: What date and time was this response sent? (Use the format: DD-MM-YYYY HH:MM)

HTTP/1.1 200 OK
Date: Tue, 13 Aug 2019 12:21:39 +0000
Server: Apache/2.2.3 (CentOS)
Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000
ETag:17dc6-a5c-bf716880.
Content-Length: 69763
Keep-Alive: timeout=44, max=71
Connection: Keep-alive
Content-type: image/html

1 points   

QUESTION 20

1. Consider the message below: What is the name of the server?

HTTP/1.1 200 OK
Date: Tue, 13 Aug 12:21:39 +0000
Server: Apache/2.2.3 (CentOS)
Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000
ETag:17dc6-a5c-bf716880.
Content-Length: 69763
Keep-Alive: timeout=44, max=71
Connection: Keep-alive
Content-type: image/html

Answer 1

Answer

QUESTION 11 1. Consider the following excerpt from a simple server side UDP program: Server.py from socket import * sName="127.0.0.1 sSocket=socket(AF_INET,SOCK_DGRAM) sSocket.bind((sName, 12005)) while True: msg, cAddr =sSocket.recyfrom(2048) newMsg = msg.decode().lower sSocket.sendto[*** What code could be used to replace the **********'s in line 8? newMsg.encode(), cAddr newMsg.encode) msg.encode(), cAddr msg.encodel none of the above 1nainte

QUESTION 13 In this architecture there is minimal or no reliance on dedicated servers Client-server P2P Network Application Layer None of the above 1 points QUESTION 14 HTTP request messages are in ---- format 7-bit ASCII Binary Text ASCII None of the above 1 points QUESTION 15 What type of a DNS RR stores the canonical hostname for the alias hostname? A NS CNAME MX None of the above

QUESTION 16 Consider the message below. What is the size of the document being returned by the server (in bytes)? HTTP/1.1 200 OK Date: Tue, 13 Aug 12:21:39 +0000 Server: Apache/2.2.3 (CentOS) Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000 ETag:17dc6-a5c-bf716880. Content-Length: 69763 Keep-Alive: timeout=44, max=71 Connection: keep-alive Content-type: image/html

Answer

69763 bytes

QUESTION 17 Consider the message below: What is the type of file being sent to the client? HTTP/1 200 OK Date: Tue, 13 Aug 12:21:39 +0000 Server: Apache/2.2.3 (CentOS) Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000 ETag:17dc6-a5c-bf716880. Content-Length: 69763 Keep-Alive: timeout=44, max=71 Connection: keep-alive Content-type: image/html

Answer

image/html

QUESTION 19 Consider the message below: What date and time was this response sent? (Use the format: DD-MM-YYYY HH:MM) HTTP/1.1 200 OK Date: Tue, 13 Aug 2019 12:21:39 +0000 Server: Apache/2.2.3 (CentOS) Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000 ETag:17dc6-a5c-bf716880. Content-Length: 69763 Keep-Alive: timeout=44, max=71 Connection: keep-alive Content-type: image/html

Answer

13-08-2019 12:43

QUESTION 20 Consider the message below. What is the name of the server? HTTP/1.1 200 OK Date: Tue, 13 Aug 12:21:39 +0000 Server: Apache/2.2.3 (CentOS) Last-Modified: Tue, 13 Aug 2019 12:43:19 +0000 ETag:17dc6-a5c-bf716880. Content-Length: 69763 Keep-Alive: timeout=44, max=71 Connection: keep-alive Content-type: image/html

Answer

Apache/2.2.3 (CentOs)

--

Explanation

11)once socket is constructed the following wcode that will send our UDP message
sendto(Message, (UDP_IP_ADDRESS, UDP_PORT_NO))

according to this format

only option a will fit

newMsg.encode(), CAddr is the correct one

--
13)in P2P architecture there is minimal or no reliance on dedicated servers
because, each and every computer can act both client and server
--
14) HTTP request messages are in ASCII format
--
15)
CNAME means Canonical Name

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Answered all the questions, excepts 2 questions, really sorry for that

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Good Luck