What is the maximum size of an IP packet?

What is the maximum size of an IP packet?

• A. 65535 bytes
• B. 65535 bits
• C. 1500 bytes
• D. 32000 bytes

Answer: (A)

In IPv4, the datagram size is defined by a 16-bit Total Length field, which specifies the entire IP packet size in bytes, header included. Since it’s 16 bits, the maximum value is 2^16 − 1, which is 65,535 bytes. So the largest IP packet you can have is 65,535 bytes in total. Remember this includes the header; the header itself can be as small as 20 bytes, leaving up to 65,515 bytes for payload in the largest case. The other options miss one of these points: using bits instead of bytes, or citing a common MTU like 1500 bytes, or an arbitrary 32,000 bytes, aren’t the defined maximums for an IP datagram.

In IPv4, the datagram size is defined by a 16-bit Total Length field, which specifies the entire IP packet size in bytes, header included. Since it’s 16 bits, the maximum value is 2^16 − 1, which is 65,535 bytes. So the largest IP packet you can have is 65,535 bytes in total. Remember this includes the header; the header itself can be as small as 20 bytes, leaving up to 65,515 bytes for payload in the largest case. The other options miss one of these points: using bits instead of bytes, or citing a common MTU like 1500 bytes, or an arbitrary 32,000 bytes, aren’t the defined maximums for an IP datagram.