Question

I NEED HELP WITH COMPUTER NETWORKS( PLEASE ANSWER THEM ALL)

CALCULATIONS & MCQS

1.

Name 1 languages that the browser is willing to accept in the following message?

GET /kurose_ross/interactive/quotation7.htm HTTP/1.1
Host: gaia.cs.umass.edu
Accept: text/plain, text/html, image/gif, image/jpeg, audio/mpeg, audio/basic, video/wmv, video/mp4, application/*, */*
Accept-Language: en, fr, de, ar, cs
If-Modified-Since: Mon, 12 Aug 2019 07:13:47 -0700
User Agent: Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko/20100101 Firefox/11.0

2.

A file of size F = 8 Gbits needs to be distributed to10 peers. Suppose the server has an upload rate of u = 68 Mbps, and that the 10 peers have upload rates of: u1 = 20 Mbps, u2 = 22 Mbps, u3 = 12 Mbps, u4 = 19 Mbps, u5 = 25 Mbps, u6 = 24 Mbps, u7 = 18 Mbps, u8 = 11 Mbps, u9 = 14 Mbps, u10 = 30 Mbps, and download rates of: d1 = 28 Mbps, d2 = 30 Mbps, d3 = 12 Mbps, d4 = 20 Mbps, d5 = 18 Mbps, d6 = 15 Mbps, d7 = 14 Mbps, d8 = 34 Mbps, d9 = 20 Mbps, d10 = 34 Mbps. What is the minimum time needed to distribute this file from the central server to the 10 peers using the client-server model (round to the nearest second)?

3.

Consider the following excerpt from a simple client side TCP program:

Client.py

from socket import *

sName=’xyz’

sPort=12002

cSocket=socket(AF_INET,SOCK_STREAM)

cSocket.connect((************))

cSocket.send (‘Welcome to Socket programming’.encode())

newText=cSocket.recv(1024)

print ('From Server:', newText.decode(), '\n')

cSocket.close()

Which of the following could be used to replace the *********** in line 5?

		sPort
		12000
		‘’, serverPort
		'',sPort
		None of the above

4.

Consider the following excerpt from a simple client side UDP program:

Client.py

from socket import *

sName=’xyz’

sPort=12002

cSocket=socket(AF_INET,SOCK_DGRAM)

cSocket.sendto(‘Welcome to Sockets’.encode())

newText, sAddr=cSocket.recvfrom(1024)

print ('From Server:', newText.decode(), '\n')

cSocket.close()

In which of the following lines of code has an error been made?

		cSocket.sendto(‘Welcome to Sockets’.encode())
		sPort=12002
		cSocket=socket(AF_INET,SOCK_DGRAM)
		sName=’xyz’
		newText, sAddr=cSocket.recvfrom(1024)

Answer 1

1. English, German, French, Arabic

2. Time to distribute F to 10 peers, using Client server

D > max(10*8 * 10⁹/68 * 10⁶ , 8*10⁹/12* 10⁶ ) = max( 1176.4, 666.7) = 1176.4 seconds.

3. Ip, Port i.e ('', sPort)

4. cSocket.sendto(‘Welcome to Sockets’.encode()) - sendto must also contain the Destination Ip.