specifications. One of the classics is 'IP over avian carriers', RFC 1149 [12]. 2.1.3 Other Important Organizations in the 3GPP-Ecosystem In the past sections, we described two of the most important standardization groups that shape the 3GPP technology, and thus, are part of the 3GPP ecosystem. However, these are not the only SDO or industry organizations that shape the industry and the technology. In the following, we shall briefly describe a few organizations that are part of the same ecosystem. GSM Association (GSMA) [13] is an organization that represents mobile operators globally. It has multiple roles, ranging from organizing the global roaming between operators, over creating technical industry specifications, to organizing the largest and most important of mobile communications events: the Mobile World Congress (MWC). Deploying IPv6 in 3GPP Networks Open Mobile Alliance (OMA) [14] is an SDO concentrating on specifying standards for mobile services. 3GPP has had, and continues to have, close cooperation with OMA over such services as the Multimedia Messaging (MMS) [15] and IMS services. ETSI is not only one of the 3GPP's founding SDOs, but 3GPP and ETSI continue to have close technical cooperation in multiple areas. 2.2 Introduction to 3GPP Network Architecture and Protocols In this section we will start to get to know the different 3GPP architectures and radio accesses. This book will concentrate on the Packet Switched (PS) domain of the 3GPP architecture, as the Circuit Switched (CS) has little relevance when talking about IP and IPv6. However, to completely understand the 3GPP system, and its architecture, one must understand a bit of the technology it has been built on. As described before, the 3GPP system has been specified in different releases where the newer ones build on the previous ones. There have been defining moments in the 3GPP release history where, in addition to adding new features, the architecture is significantly altered. Obviously, the first defining architectural event was the defini