Taxation begins at the time of exercise. The bargain element of a non-qualified stock option is considered compensation and is taxed at ordinary income tax rates. For example, if an employee is granted 100 shares of Stock A at an exercise price of $25, the market value of the stock at the time of exercise is $50.
In the Internet Protocol version 4 (IPv4) [RFC791] there is a field called Protocol to identify the next level protocol. This is an 8 bit field. In Internet Protocol version 6 (IPv6) [RFC2460], this field is called the Next Header field. Values that are also IPv6 Extension Header Types should be listed in the IPv6 Extension Header Types registry at [IANA registry ipv6-parameters].
In IPv4, every IP address comes with a corresponding subnet mask. IPv6 also uses subnets, but the subnet ID is built into the address. In an IPv6 address, the first 48 bits are the network prefix. The next 16 bits are the subnet ID and are used for defining subnets.