Section: 6.1.2A.1.1 Interworking with PDN based on IP
Content: During PDP context activation (see subclause 6.1.3.1), the MS can configure an IPv4 address, or obtain an IPv6 interface identifier to be used during the IETF-based IP address allocation after PDP context establishment. The MS can obtain an IPv4 address or an IPv6 prefix via an IETF-based IP address allocation mechanism once the PDP context is established. The following IETF-based IP address/prefix allocation methods are specified for GPRS (the corresponding procedures are specified in 3GPP TS 29.061[ Interworking between the Public Land Mobile Network (PLMN) supporting packet based services and Packet Data Networks (PDN) ]  [130]): a) /64 IPv6 default prefix allocation via IPv6 stateless address autoconfiguration. Optionally, allocation of additional IPv6 prefix(es) with length /64 or shorter via stateful DHCPv6 Prefix Delegation (see IETF RFC 3633 [139]); b) IPv4 address allocation and IPv4 parameter configuration via DHCPv4; Upon deactivation of a default PDP context, the MS shall locally release any IPv4 address or IPv6 prefix allocated to the MS for the corresponding PDN connection.