P standards offer two basic methods for ensuring that a UE gets anchored to the correct PGW. Both methods rely on the HLR/HSS subscription profile and its per APN configuration: The static IPv4 address and/or IPv6 prefix are provisioned under an APN that always resolves to a specific PGW. This method works also when the subscription profile is retrieved from an HLR. The APN configuration profile in an HSS may contain a PGW identity (i.e., a Fully Qualified Domain Name FQDN) or an IP address of a statically assigned PGW (see the MIP6-Agent-Info AVP [110-112] for the S6a/S6b/STa-interfaces). Based on the Deploying IPv6 in 3GPP Networks downloaded subscription profile, the MME or the S4-SGSN can locate the proper PGW where the statically assigned IPv4 addresses and IPv6 prefixes are also provisioned. As a side note, in this case the MME would have two sources from which to locate the proper PGW: the APN and the PGW identity. The PGW identity should take precedence in this case, since depending on the PGW 'IP architecture' the PGW may still be provisioned into the DNS as a multi-homed node and the APNs FQDN [113] could resolve to multiple IP addresses, whereas the PGW identity identifies exactly one IP address. Camping a set of UEs always to specific PGWs can be both a scalability and a non- optimal routing issue. Some vendor products allow PGWs dynamically to advertise the address blocks that they have, using routing protocols such as Open Shortest Path First (OSPF) or Border Gateway Protocol (BGP). The use of dynamic routing could solve the issue of camping UEs (or rather subscribers) to a specific PGW, and instead let the normal gateway selection procedure select and assign a PGW to a PDN Connection. However, in the event of UEs starting to roam around making it impossible to maintain proper aggregation, there is a risk that an unbearable amount of host routes would get advertised in the routing system. Therefore, the use of static IP addressing should be carefully evaluated before being deployed in a large scale.