Brief description of each IP datagram header field
# version (ver). This 4 bit field defines the version of the IP protocol
# header length (HLEN). This 4 bit field defines the total length of the datagram header in 4 byte words. For example, when the header length is 20 bytes, the value of this field is 5 (5x4=20)
# differentiated service (DS). IETF has changed the interpretation and name of this 8 bit field. This field, previously called service type, is now called differentiated services