Fig. 1: IPv4 and IPv6 packet header formats The TOS field was redefined in IPv4 to contain two values—the 6-bit DSCP (Differentiated Services Code Point) field, and the 2-bit ECN (Explicit Congestion ...

IPv4 is running out of steam and companies are finally starting to switch to IPv6. So what is the difference between the two and why should you be using IPv6.

The length of an IPv4 packet’s header varies, and thus requires the use of a header length field. IPv6 uses 40 bytes in an eight-field header.