Just got an simple question.Its abt reading a plane IP packet. In a standard IP packet RFC 791, there are multiple fields, the IP packet header size is 20 bytes. Now when i look at following packet and see the highlighted sections i see Version is IPv4 and header length is 20 bytes (which is true and we ack that).However the binary values on the left side are confusing . For the version the binary value is 0100 which is decimal is 4 and is true (IPv4) but for Header length the binary is 0101 which should be 5 but it shows 20 bytes!!!! How? Also since the IHL (IP header length) field in IP header is only 4 bits the max decimal value can only be 15 (if 1111). Now how come it can show the header length as 20. Now sure what u am missing but i request experts to take a moment to answer this.