Problem 1.

Given a networking scenario below in Figure 1 and an Ethernet

frame (in the format of hexadecimal numbers) transmitted from Host A to Host B

that is captured by Wireshark as illustrated in Figure 2,

Figure 1: Networking scenario from Host A to B

Host A

Network 1

Network 2

a set of routers

Host B

00 26 b9 e8 7e f1 00 12 f2 21 da 00 08 00 45 00

05 dc e3 cd 20 10 35 06 25 eb 0a 0a 0a 02 c0 a8

01 03 c3 9e 0f 40 00 00 10 00 00 00 14 00 70 10

00 5c 59 99 00 00 02 04 05 b4 01 03 03 06 00 00

01 98 64 34 e8 90 84 98 20 12 18 19 04 85 80 00

Figure 2: Ethernet frame transmitted from Host A to Host B

Decoding the above Ethernet frame and answer the following questions:

(a) Decapsulate the Ethernet frame and what is the protocol name used in

Network layer and Transport layer, respectively.

(5 points)

(b) Decode the Ethernet frame and find the IP address of Host A and Host B,

respectively. Suppose in Figure 1 the subnet mask for Network 1 is /26

and the subnet mask for Network 2 is /25, according to the IP addresses

of Host A and B, what is the subnet address for Network 1 and Network 2,

respectively.

(10 points)

(c) Indicate how many more routers can the Ethernet frame travel to during

the transmission from Host A in Network 1 to Host B in Network 2?

(5 points)

(d) Indicate the size of the data after decapsulating all protocol header

information and determine if there is any information missed in this

Ethernet frame?

(10 points)

(e) Is the datagram in the Ethernet frame fragmented? If yes, please give the

number of the first byte and number of the last byte in the fragmented

datagram?

(15 points)

(f) According to the above Ethernet frame, if TCP is used in the transport

layer, please give the window size of the TCP segment; if UDP is used in

the transport layer, please then indicate the source port number and

destination port number in the UDP segment?

(20 points)

(g) Assume the data transmission occurs only in between Host A and Host B,

analyze the above Ethernet frame, and determine how many bytes the

Host A have received successfully from Host B?