Question 27 4 pts Suppose that you're at home and you're trying to download a web page at lucas.cis.temple.edu. You do not know the IP address of lucas.cis.temple.edu and it's not cached at any name server other than its authoritative name server, dns.temple.edu. Your local name server is dns101.comcast.net. Assume that all of the delays in the figure above are one-way, and are in milliseconds. How long does it take if your local name server does it take. Choose the correct answer for iterated root 71 16 15 28 com 6 edu 85 22 11 37 18 14 23 15 dns101.comcast.net dns.temple.edu 26 91 23 you 11 lucas.cis.temple.edu O 3 + 28 + 18 + 15 + 8 + 11 ms None of the above 213 +28 + 18 + 15) ms O2(3 + 11 + 18 + 15) ms Question 28 2 pts Suppose that you're at home and you're trying to download a web page at lucas.cis.temple.edu. You do not know the IP address of lucas.cis.temple.edu and it's not cached at any name server other than its authoritative name server, ns.temple.edu. Your local name server is dns101.comcast.net. Assume that all of the delays in the figure above are one-way, and are in milliseconds. How long does if your local name server does it take. What is the correct answer for recursive? root 71 16 15 28 com 6 edu 85 22 37 14 23 18 dns101.comcast.net 15 pns.temple.edu 26 91 41 8 23 you 11 lucas.cis.temple.edu O 2(3 + 28 + 15 + 14) miliseconds O 3+ 11 + 16 + 15 + 14 + 8 + 11 milliseconds 2(3 + 28 + 18 + 15 +26) milliseconds O 2(3 + 28 + 15 + 14 + 8) milliseconds D Question 29 4 pts Host A and B are communicating over a TCP connection and Host B had already received from A all bytes up through byte 149. Suppose Host A then sends two segments to Host B back to back. The first and second segments contain 80 and 40 bytes of data respectively. In the first segment, the sequence number is 150, the source port number is 202, and the destination port number is 80. Host B sends an acknowledgement whenever it receives a segment from Host A. In the second segment, sent from Host A to B, what is the sequence number and destination port number? Host A Host B Seq=150, 80 bytes meout terval Seq = 40 bytes Ack = 230 Ack = Seq = 150, 80 bytes Ack - Timeout interval seq #270, 40 bytes destination port#80 Seq# 202, desination port#80 seq #230, 40 bytes ,destination port# 80 seq #150,80 bytes, destination port# 80 Question 30 4 pts Host A and B are communicating over a TCP connection and Host B had already received from A all bytes up through byte 149. Suppose Host A then sends two segments to Host B back to back. The first and second segments contain 80 and 40 bytes of data respectively. In the first segment, the sequence number is 150, the source port number is 202, and the destination port number is 80. Host B sends an acknowledgement whenever it receives a segment from Host A. If the second segment arrives before the first segment, in the acknowledgement of the first arriving segment, what is the acknowledgement number sent from Host B. Host A Host B Seq - 150, 80 bytes meout terval Seq. 40 bytes Ack=230 Ack Seq-150, 80 bytes Ack Timeout interval ACK#270 ACK#202 ACK#80 ACK#230
