4. On the row immediately above the vertical lines, find the lowest number that covers the needed hosts and circle it, as shown in Figure 4-22. This is your magic number that youll use in your calculations shortly. In Figure 4-22, the magic number is 16, which is the lowest number that will give you 15 subnets. # of subnets- 8 46 32 40 2 4 32 64 128 256 128 64 4 Magic number 128 192 224 240 248 252 254 255 New interesting octet

Server Host A SYN Seq 0 SYN JACK Seq=0, ACK=1 ACK Seq, ACK Seq=? ACK=? 170 bytes Get Req Seq and ACK values are: a. Seq=1, ACK=0 b. None is true. c. Seq=0, ACK=1 d. Seq=0, ACK=0 e. Беq-1, ACK-1 С.

The following message arrived protected by the following CRC polynomial. Does the message have an error or not? Why?   In the below table, show your work that allowed you to make the determination of whether an error exists in the message or not. Add rows and columns to the below table as necessary. M(x): 11010011100011  CRC-3-GSM:  x3 + x + 1 CRC that was in the message: 011     X0       T(x)         C(x)         Remainder

0. AS1 has the following routing table, draw the network of AS’s that these paths imply: prefix            path P1                 AS2 P2        AS4 AS5 AS3 P1             AS4 AS2 P2             AS5 AS3 P1             AS5 AS2   Assuming AS 1 accepted all the paths advertised to it, what paths does AS4 advertise to AS1? What AS is P1 in? What about P2? AS5 no longer wants to forward packets destined for prefix P1 on behalf of AS1, but it is ok forwarding prefix P2, how would it change the paths it advertises to AS1? If AS1 sends a packet to AS4 destined for P1, what path will it take? How do we know AS4 won’t forward it back to AS1? If AS1 gets the following advertisement from AS4, P1 AS4 AS1 AS2 how would it update its table? Why? NOTE: I would appreciate it if the solutions of the paths were hand-drawn so I can visualize it better.

1. Please access any web site so you that you can capture TCP packets from an HTTP request. 2. Please expand all the fields in the header of your HTTP request packet. Take a screenshot for all the fields in the header fields of the HTTP packet. 3. Please expand all the fields in the header of the TCP packet in your HTTP request packet. Take a screenshot for all the fields in the header of the TCP packets. Please answer the following questions based on your HTTP request, and TCP packets screenshots: 1. What is the method used in your HTTP request? 2. What is the host name you visited? 3. What is the connection status in your HTTP request? 4. What are the source port and destination port, respectively? 5. What are the sequence number and acknowledgement number, respectively? 6. Which flags are set up in the captured packet? Explain what the flags mean.