How big is the smallest packet that will always be fragmented on a standard Ethernet network with default configuration?

How big is the smallest packet that will always be fragmented on a standard Ethernet network with default configuration?
A. 1500 bytes
B. 1800 bytes
C. 2048 bytes
D. 2100 bytes

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6 thoughts on “How big is the smallest packet that will always be fragmented on a standard Ethernet network with default configuration?

  1. This is the definition from Wendell Odom’s CCNA book on MTU:

    The IEEE 802.3 specification limits the data portion of the 802.3 frame to a minimum of 46 and a maximum of 1500 bytes. The term maximum transmission unit (MTU) defines the maximum layer 3 packet that can be sent over a medium. Because the layer 3 packet rests inside the data portion of an Ethernet frame, 1500 bytes is the largest IP MTU allowed over an Ethernet.

    Answer would be B.

  2. B

    The keyword of the question is packet. Standard Ethernet allows for a FRAME size of 1522 octets/bytes which has a PACKET payload of up to 1500 octets/bytes. Answer A, 1500 bytes, would not need to be fragmented, therefore answer B is the smallest packet that would need to be fragmented.

    Reference for standard Ethernet Frame
    https://en.wikipedia.org/wiki/Ethernet_frame

  3. answer is b.. standard frames are 1500 and therefore will not be fragmented. all the other answers will be fragmented and hence the “smallest “part of the question is 1800

  4. A

    https://www.cisco.com/c/en/us/support/docs/ip/transmission-control-protocol-tcp/200932-Ethernet-MTU-and-TCP-MSS-Adjustment-Conc.html

    The MTU is the maximum length of data that can be transmitted by a protocol in one instance. For example, the MTU size of an Ethernet interface is 1500 bytes by default, which excludes the Ethernet frame header and trailer, which means, that the interface cannot carry any frame larger than 1500 bytes.This diagram visualizes this concept:

    1. As I understood from the explanation (the interface cannot carry any frame larger than 1500 bytes), means that a frame of size 1500 bytes will not be fragmented, but any frame larger than 1500 will be fragmented.
      so, 1800, 2048 & 2100 will be fragmented, 1800 is the smallest amongst those three options. so (B) is correct.

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