Maximum Transmission Unit & Maximum Segment Size

                    <--------------------------- IP MTU ------------------->
                    <--------------------- Ethernet MTU ------------------->
                                               <--------- TCP MSS --------->
       +------------+------------+-------------+---------------------------+------------+
FRAME  | Eth-Header |  IP-Header |  TCP-Header |           Data            | Eth-trailer|
       +------------+------------+-------------+---------------------------+------------+
BYTES        14           20            20                 1460                  4

Data Size

Data	Minimum Size	Maxmum Size	Reasons
IPv4 packet	20 Bytes	65535 Bytes	16-bit Total Length field in the IPv4 header can store values from 0 to 65535. Since IP header is 20 bytes which defines the minimal.
Ethernet frame	64 Bytes	1518 Bytes	In the original Ethernet standard (10 Mbps), the minimal ethernet frame size is 64 bytes and Etherent MTU is 1500 bytes.