ut duplication. Packet Data Network (PDN) PDN can be an internal walled garden like an IP network within the mobile operator network, or any IP network outside operator administration such as the Internet. Glossary xxxix Packet Data Network Gateway (P-GW, PGW, or PDN-GW) The gateway between the EPS and the external IP networks, and the anchor point for EPS mobility management. From a UE's IP-stack point of view PGW is the first-hop router. Path Maximum Transmission Unit (MTU) Discovery A process for finding the small- est MTU on the links on the path from sending node to receiving node. Pointer (PTR) resource record A DNS resource record that points to a hostname. Used for reverse DNS queries - to find which name maps to an address. Protocol translation An important IPv6 transition tool is protocol translation, which refers to the process of translating IPv6 packets into IPv4 (NAT64) or IPv4 packets into IPv6 (NAT46). Provisioning Technologies and processes used for automatic configuration of hosts with information needed for accessing networks. Radio Access Network The 'last mile' connectivity from core network to the edge, for example to hosts. In 3GPP 4G the access network includes eNodeB, in 3G it includes eNodeB and RNC, and in 2G it includes BTS and BSC. Referred in 2G also as GERAN, in 3G as UTRAN, and in 4G as E-UTRAN. Radio Access Network Application Part (RANAP) UMTS protocol that carries the higher layer signaling. It runs on the Signaling System No. 7 (SS7) protocol suite. Originally the Iu-interface was specified to be transported only on ATM. However, the standard has been updated to enable any transport network technology to be used. Radio Network Controller (RNC) Controls a group of NodeBs and handles mobility management between the NodeBs under its control. Request For Comments (RFC) Permanent documents created by IETF. The RFCs that represent IETF's consensus are, for example, classified as Standards Track or Best Current Practice (BCP). A standards track RFC is usually a protocol specification 