ew, the GGSN and the PGW are the first IP-aware packet core element for GTP-based Gn-, Gp-, and S5/S8-interfaces. In the case of the PMIP-based S5/S8-interface, the SGW is the first IP-aware packet core element. In addition to GTP-level IPv6 impacts (see Section 4.3), the PGW supports multiple IP router and access gateway level functions that also have to be enabled for IPv6 support. These functions include the following: DHCPv6 server function [25, 26]. Until Release-10 only the stateless mode of DHCPv6 operation for additional parameter configuration was supported [54]. However, introduction of the DHCPv6 PD added a stateful mode of operation to it [27, 55]. DHCPv6 client function [25, 26]. Remote Authentication Dial In User Service (RADIUS) and/or Diameter client func- tion [25]. The attributes and AVPs have to have IPv6 support implemented for IPv6 values and content. Basic routing and respective routing protocols such as the Open Shortest Path First version 3 (OSPFv3) [56] and/or the Multi-Protocol Border Gateway Protocol (MP- BGP) [57]. In case of MBMS, a GGSN also has to understand IPv6 SSM [50] along with the Multicast Listener Discovery version 2 (MLDv2) [51, 52]. Table 4.3 summarizes the user plane IPv6 impact of the PGW elements depending on the 3GPP release. Additionally, the PGW may also include firewall, various flavors of Network Address Translation (NAT) and Deep Packet Inspection (DPI) functions depending on the vendor. However, these functions are not part of the 3GPP standards. Most, if not all PGW products also support local configuration of subscription profiles (or session profiles, APN configurations depending on the vendor). This implies that the product has to understand basic subscription configurations such as: IPv6 prefix pools, IPv6 Domain Name System (DNS) server addresses [58], and Proxy Call Session Control Function (P-CSCF) addresses to name but a few. The PGW also has Policy and Charging Control (PCC) [59] Policy and Charging Enforcement Function (PCEF) and a number of charging r