Question

An IP packet to be transmitted by Ethernet is 60 bytes long, including all its headers. If LLC is not in use, is padding needed in the Ethernet frame, and if so, how many bytes?

Answer 1

Yes, 4 bytes of padding are needed for a 60-byte IP packet to be transmitted by Ethernet without LLC, to meet the 64-byte minimum frame size.

Step-by-step explanation:

You asked whether padding is needed for an IP packet of 60 bytes to be transmitted by Ethernet if LLC is not used. The answer is yes, padding is needed.

This is because the minimum Ethernet frame size is 64 bytes. Given that the IP packet is already 60 bytes, including headers, and assuming that LLC is not in use, this packet will need an additional 4 bytes of padding to meet the Ethernet frame minimum size requirement. Therefore, an Ethernet frame carrying this IP packet would be sized to 64 bytes, with 4 bytes of padding added to the original 60-byte packet.

Answer 2

No padding

Step-by-step explanation:

64 bytes is taken as the minimum Ethernet frame, this encompass checksum as well as addresses in the Ethernet frame header and length field. while the maximum Ethernet frame is 1518 bytes, any minimumEthernet frame that is short compare to that will need receiving stations to interpret it as a collision. The question specified that the IP packet to be transmitted by Ethernet as 60 bytes long. The header fields here can occupy 18 bytes, Then total frame size becomes 78 bytes. With the total frame size of 78 bytes(60 bytes+ 18 bytes) we can see it has exceeded the 64-byte minimum. Hence there is no padding used.