accesses, but also with typical pros such as tight integration which can bring security and ease-of-use benefits. A thing common to all 3GPP solutions is the utilization of a new Access Network Discovery and Selection Function (ANDSF) [4], which is needed for providing operator policies to the User Equipments (UEs) [5]. Only time will tell how widespread the adoption of 3GPP offloading solutions will be among the various general purpose Operating System (OS) vendors, especially if the 3GPP's solution, namely the ANDSF, is not needed for any other purposes. In fact, it is not yet well understood what level of management burden the 3GPP operators themselves are willing to bear for micromanaging IP traffic offloading policies. In this section we will look in more detail at how different Internet Engineering Task Force (IETF)-defined IPv6-based offloading solutions work. The IP version agnostic 3GPP specific solutions are left for other books and for the referenced 3GPP documents to describe. When it comes to Internet Protocol version 4 (IPv4) offloading, we do not believe that it is a justified use of time to try to specify sophisticated IPv4-based offloading solutions, as the future is in IPv6. The exhausted IPv4 address space, with widespread use of private IPv4 addresses, creates addressing conflicts and therefore makes the address and router selection process hard. 6.1.1 Motivations in Cellular Networks Originally, the 3GPP General Packet Radio Service (GPRS) architecture adopted a point- to-point approach for network access. This is visible, for example, in how the mobile Deploying IPv6 in 3GPP Networks device - the UE - sees the network connection, the network interface, and how the connection between the UE and the network is realized. The point-to-point connection between the UE and the external Packet Data Network (PDN) is referred to as a PDP context or a PDN connection. Traditional phones (see Section 2.6.1) typically have a silo view of the network con- nectivity for a single application or a group of ap