Section: 6.1.3.1 PDP context activation
Content: The purpose of this procedure is to establish a PDP context between the MS and the network for a specific QoS on a specific NSAPI. The PDP context activation may be initiated by the MS or the initiation may be requested by the network. An MS attached for emergency bearer services shall only request a PDP context with request type set to "emergency". If there already is a PDN connection for emergency bearer services established, the MS shall not request an additional PDN connection for emergency bearer services. The MS shall not request emergency bearer services in A/Gb mode or in GERAN Iu mode. If the MS has reached the maximum number of active PDP contexts (see subclause 6.1.3.0) and the upper layers of the MS request activation of additional PDP context, then the MS shall not send an ACTIVATE PDP CONTEXT REQUEST message or an ACTIVATE SECONDARY PDP CONTEXT REQUEST message to activate the additional PDP context. If the additional PDP context is a PDP context with type set to "emergency", then it may skip explicit deactivation to free PDP context resources and instead re-activate the necessary context(s) relying on network handling of abnormal cases as specified in subclause 6.1.3.1.5 case c). In either case it is an MS implementation option which PDP context(s) to re-use for emergency. Each PDP address may be described by one or more PDP contexts in the MS or the network. The PDP Context Activation procedure is used to activate the default PDP context for a given PDP address and APN, i.e. a PDN connection, whereas all additional contexts associated to the same PDP address and APN are activated with the secondary PDP context activation procedure. An MS supporting S1 mode shall keep the default PDP context activated during the lifetime of the PDN connection. An MS not supporting S1 mode should apply the same behaviour (see 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74]). When more than one PDP context is associated to a PDP address, there shall be a Traffic Flow Template (TFT), including one or more packet filters, for each or all but one context. The downlink and uplink packet filters are considered separately. If present, the TFT shall be sent transparently either from the MS via the SGSN to the GGSN to enable packet classification and policing for downlink data transfer in the GGSN or from the GGSN via the SGSN to the MS to be used in a network requested secondary PDP context activation procedure (see subclause 6.1.3.2) and enable packet classification and policing for uplink data transfer in the MS (see 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74]). For the purpose of requesting non-IP connectivity, the MS shall set the PDP type number in the Requested PDP address information element in the ACTIVATE PDP CONTEXT REQUEST message to "non IP". The MS supporting non-IP connectivity shall also support the extended protocol configuration options IE. For the purpose of requesting IP address allocation the MS shall set the PDP type number in the Requested PDP address information element in the ACTIVATE PDP CONTEXT REQUEST message based on its IP stack configuration (e.g. the per APN settings specified in 3GPP TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [74]) as follows: a) An MS, which is IPv6 and IPv4 capable, and - has not been allocated an IP address for this APN, shall set the PDP type number to "IPv4v6 address"; - has been allocated an IPv4 address for this APN and received the SM cause #52, "single address bearers only allowed", and is requesting an IPv6 address, shall set the PDP type number to "IPv6 address"; - has been allocated an IPv6 address for this APN and received the SM cause #52, "single address bearers only allowed", and is requesting an IPv4 address, shall set the PDP type number to "IPv4 address". b) An MS, which is only IPv4 capable, shall set the PDP type number to "IPv4 address". c) An MS, which is only IPv6 capable, shall set the PDP type number to "IPv6 address". d) When the IP version capability of the MS is unknown in the MS (as in the case when the MT and TE are separated and the capability of the TE is not known in the MT), the MS shall set the PDP type number to "IPv4v6 address". On receipt of the ACTIVATE PDP CONTEXT REQUEST message sent by the MS, the network when allocating an IP address shall take into account the PDP type number, the operator policies of the home and visited network, and the user's subscription data. - If the MS requests PDP type IPv4v6, but the network configuration dictates the use of IPv4 addressing only or IPv6 addressing only for this APN, the network shall override the PDP type requested by the MS to a single address PDP type (IPv4 or IPv6). In the ACTIVATE PDP CONTEXT ACCEPT message sent to the MS, the network sets the PDP type number to either "IPv4 address" or "IPv6 address" and the SM cause to #50 "PDP type IPv4 only allowed", or #51 "PDP type IPv6 only allowed", respectively (see subclause 6.1.3.1.1). - If the MS requests PDP type IPv4v6, but the operator uses single addressing per PDP context due to interworking with nodes of earlier releases, the network shall override the PDP type requested by setting the PDP type in the ACTIVATE PDP CONTEXT ACCEPT message sent to the MS to a single address PDP type. In the ACTIVATE PDP CONTEXT ACCEPT message sent to the MS, the network sets the PDP type number to either "IPv4 address" or "IPv6 address" and the SM cause to #52, "single address bearers only allowed" (see subclause 6.1.3.1.1). The MS, in a pre release 8 network not supporting IPv4/v6, could encounter other network reactions: - If the MS requests PDP type IPv4v6, and the PDP type is changed to PDP type IPv4 and no SM cause is included, the MS should request another PDP context for PDP type IPv6 to the same APN. NOTE: Some networks can respond with ACTIVATE PDP CONTEXT REJECT with SM cause #28 "unknown PDP address or PDP type". In that instance, the MS can attempt to establish dual-stack connectivity by performing two PDP context activation request procedures to activate an IPv4 PDP context and an IPv6 PDP context, both to the same APN.