6.1.2A PDP address allocation
24.0083GPPCore network protocolsMobile radio interface Layer 3 specificationRelease 18Stage 3TS
6.1.2A.1 General
PDP addresses are handled differently for PDN interworking of type PPP and IP (IPv4 or IPv6).
6.1.2A.1.1 Interworking with PDN based on IP
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 [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.
6.1.2A.1.2 Interworking with PDN based on PPP
During PDP context activation no PDP address is configured. Instead, such information is negotiated and configured during the NCP phase of PPP.
6.1.2A.2 IP address allocation via NAS signalling
The MS shall set the PDP type in the PDP address IE in the ACTIVATE PDP CONTEXT REQUEST message when requesting establishment of a default PDP context; the detailed rules with regards to IP version for MS and network side are defined in subclause 6.1.3.1.
If the MS wants to use DHCPv4 for IPv4 address assignment, it shall indicate that to the network within the Protocol Configuration Options IE in the ACTIVATE PDP CONTEXT REQUEST.
If the MS requests allocation of an IPv6 address, the network constructs it of two parts: a /64 IPv6 prefix and an interface identifier of 64 bits length. The IPv6 prefix part is not used immediately by the MS; however, the network shall use the same IPv6 prefix in subsequent procedures for IETF-based IP address allocation. The interface identifier is only used for building a unique link-local IPv6 address.