The IPv6 "Hop Limit" field is the only field in the IPv6 base header that is handled specially for AD calculation. The value of the Hop Limit field is set to zero for the purpose of calculation. All other fields in the base IPv6 header are included in the AD calculation using the normal procedures for this process.

All IPv6 "Option Type" values contain a bit that is used to determine whether that option data will be included in the AD calculation. This bit is the third-highest-order bit of the IPv6 Option Type field. If this bit is set to zero, then the corresponding option that's included in the AD option is replaced by all zero bits of the same length as the option, for the purpose of the AD calculation.

The IPv6 routing header "Type 0" will rearrange the address fields within the packet during transit from source to destination. Any potential problems with this are avoided because the contents of the packet as it will appear at the receiver are already known to the sender and to all intermediate hops. So, the IPv6 Routing Header "Type 0" is included in the AD calculation using the normal procedure.