n Multi- Level Security networking environments is defined in the informational RFC 5570 [33]. This option comes with an Internet Engineering Steering Group (IESG) warning to not use it in the global Internet, but only in closed networks. This is not used in 3GPP networks, and hence we are not going to look at it in any more depth. Simplified Multicast Forwarding Duplicate Packet Detection Option (experimental): This Hop-by-hop option is used in a simplified multicast forwarding mechanism defined in experimental RFC 6621 for mobile ad hoc and wireless mesh networking use [34]. Since such networks are not the scope of this book, we are not looking at this in any more depth either. Home Address (HoA) Option: The Mobile IPv6 (MIPv6) technology uses a destination option for a Mobile Node (MN) away from its home link to use in its IPv6 packets for informing recipients about the MN's home IPv6 address, as the packet's source IPv6 address is MN's Care-of Address (CoA) [35]. See more in Section 3.7.2. Routing Protocol for Low-power and Lossy networks (RPL) Option: The RPL Hop- by-hop option is used in low-power networks to convey routing information in every packet that a router forwards [159]. These low-power networks are not the focus of this book, and hence we are not looking at the RPL protocol in depth. Options for experimentation: Eight option types are reserved for experimentation purposes by RFC 4727 [36]. These experimentation options can be used with both Hop-by-hop and Destination option headers. We will not look at these in any more depth other than to list them here for the sake of completeness. For the changes since the printing of this book, please see the IANA's list of 'IPv6 Parameters' available at http://www.iana.org/assignments/ipv6-parameters/ipv6- parameters.xml. Routing Header The idea of the Routing Header is that the sender can list intermediate nodes through which the packet should traverse on its way to the destination. Deploying IPv6 in 3GPP Networks The Type 0 Routing Header [21] was deprecat