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].
Prerequisites. With 6to4 tunnels, the tunnel destination is determined by the border router IPv4 address, which is concatenated to the prefix 2002::/16 in the format 2002: border-router-IPv4-address ::/48. The border router at each end of a 6to4 tunnel must support both the IPv4 and IPv6 protocol stacks.