IPV4 Harder Numerical from Computer Networks

Question

An IPv4 datagram has arrived with the following information in the header (in hexadecimal): Ox45 00 00 54 00 03 58 50 20 06 00 00 7C 4E 03 02 B4 OE OF 02

a. Is the packet corrupted?

b. Are there any options?

c. Is the packet fragmented?

d. What is the size of the data?

e. How many more routers can the packet travel to?

f. What is the identification number of the packet?

g. What is the type of service?

Answer 1

a. It is not possible to determine whether the packet is corrupted based on the information provided.

b. The value "45" in the first byte of the header indicates that there are no options present in the packet.

c. The value "00" in the third and fourth bytes of the header indicates that the packet is not fragmented.

d. The value "54" in the fifth and sixth bytes of the header indicates that the size of the data in the packet is 84 bytes.

e. The value "06" in the seventh byte of the header indicates that the packet can travel to 6 more routers before reaching its destination.

f. The value "00 00" in the eighth and ninth bytes of the header indicates that the identification number of the packet is 0.

g. The value "50" in the tenth byte of the header indicates that the type of service for the packet is "low delay." This means that the packet should be given priority in the network to minimize delay.

Answer 2

Here are the answers to the questions based on the information provided in the IPv4 datagram header:

a. Is the packet corrupted?

Based on the information provided, it does not appear that the packet is corrupted.

b. Are there any options?

Based on the information provided, it appears that there are no options in the packet.

c. Is the packet fragmented?

Based on the information provided, it appears that the packet is not fragmented.

d. What is the size of the data?

The size of the data can be calculated by subtracting the size of the header from the total length field in the header. The total length field is 00 54, which is 84 in decimal. The size of the header can be calculated by multiplying the header length field (45) by 4, which gives a header size of 180 bytes. The size of the data is therefore 84 - 180 = -96 bytes.

e. How many more routers can the packet travel to?

The time to live (TTL) field in the header indicates the number of routers that the packet can travel to before it is discarded. The TTL value is 00 54, which is 84 in decimal. Therefore, the packet can travel to 84 more routers before it is discarded.

f. What is the identification number of the packet?

The identification number of the packet is 00 03 58 50, which is 13872 in decimal.

g. What is the type of service?

The type of service is 20, which indicates that the packet is a normal service (not high priority or low delay).

Comments

HOW CAN SIZE OF DATA BE NEGATIVE? SEE carefully header lengthis not 45 instead 5,so 5*4=20B and total length =84B

Data size=84-20=64B

time to live is (20)hex =32 routers

id no is 3

type of service ; 0 no service