IP is a widely used network layer technology, providing transport services to a huge array of network traffic around the globe. Mobile service providers use IP extensively, both in the core and radio access network in order to carry signalling and user plane traffic. For instance, LTE (Long Term Evolution) is based on IP transport on an end to end basis. IP will provide a variety of services to higher layer protocols, including network level addressing to ensure end to end delivery, QoS packet marking, payload identification, protection against unroutable packets and packet fragmentation (although this is rarely used).There are 2 versions of IP currently in existence: IPv4 and IPv6. IPv4 has seen considerable deployment to date, but is limited in terms of the number of unique IP addresses it has available. Conversely, although IPv6 has seen a lower volume of deployment, its addressing capacity is significantly greater.