Applied Mock Test

Question

Consider an IP packet with a length of 2000 bytes which includes a 20-byte header . The packet is forwarded to an IPv4 router that supports a Maximum Transmission Unit (MTU) of 400 bytes. Assume that the length of the IP header in all the outgoing fragments of this packet is 20 bytes. The fragmentation offset value stored in the third fragment is _______.

Answer 1

mtu = 400bytes,

header = 20 bytes,

data in one frame = 400 – 20 = 380

380 is not divisible by 8 but 376 is so the frame becomes

376-databytes and 20-header

376/8 = 47

fragment offset of 1^st frame is 0, 2nd→ 47, 3→ 94

so answer is 94