h other fragment (and possible predictable identifier) based attack towards the victim and third-party host. One example is 'simple' polluting of the fragment identifier space of the third-party host by the attacker sending spoofed overlapping fragments to the third-party host and effectively causing all communication from the victim host to be discarded at the third- party host. Are the above attacks and vulnerabilities issues in the 3GPP architecture? They potentially are, and there is really no difference compared to any other (fixed network) IPv6 deployment. 4.11 Chapter Summary This chapter described how the user plane IPv6 is integrated into the 3GPP architecture and which packet core networking nodes are affected by the introduction of the user plane IPv6. We explain how the 3GPP point-to-point link model works and the specifics of IPv6 on it. The IPv6 address assignment, management, and provisioning are discussed in detail. The static addressing has not been forgotten either. We also looked into the lower layers and control plane protocols, in order to point out places where user plane IPv6 information gets exchanged between the packet core network elements and also to the UE. The impact of the user plane IPv6 in mobile devices was also discussed in detail. Known issues in existing IPv6 deployments were also discussed and their root causes were revealed to the extent that the authors are aware of them. We also discussed in many places where 3GPP specifications are 'not there yet' or they contradict each other. Finally we took a look at a number of known IPv6 security issues and reflect them to the 3GPP architecture. In summary, we can say that there is still a lot that could be done better regarding IPv6 in 3GPP Networks. This comes from the fact that deployments using IPv6 in real live 3GPP networks are few and operational aspects are still in their infancy. Needless to say, the packet core networking products still have a lot to catch up, mainly due to the lack of feature enhancements originating in ope