Question 36
What is the minimum IPv4 header size?
Detailed Solution
IHL=5 is the minimum, and 5$\times 4 = 20 bytes$.
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GATE CSE Network Layer – Computer Networks Practice Test | Set 1
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Question 37
Which IPv4 header field is used to identify the upper-layer protocol carried in the payload?
Detailed Solution
The Protocol field identifies the next protocol, such as TCP (6) or UDP (17).
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Question 38
Which IPv4 header field specifies the total size of the datagram, including header and payload?
Detailed Solution
Total Length includes both the IPv4 header and payload.
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Question 39
A router decreases the IPv4 TTL from 5 to 4. Which additional header computation is required in IPv4?
Detailed Solution
Because TTL changes, the IPv4 header checksum must be updated. TCP checksum is not recomputed merely because TTL changes.
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Question 40
Which ICMP message is normally generated when a router discards a packet because its TTL reaches zero?
Detailed Solution
ICMP Time Exceeded reports TTL expiration during transit.
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