9.1 Definition of Packet Data Protocol States

23.0603GPPGeneral Packet Radio Service (GPRS)Release 17Service descriptionStage 2TS

9.1.0 General

A PS subscription contains the subscription of one or more PDP addresses. Each PDP address is an element of a PDP context. The same PDP address may appear in one or more PDP contexts in the MS, the SGSN, the S‑GW, the P‑GW and the GGSN. Each PDP context may be associated with a TFT. At most one PDP context associated with the same PDP address may exist at any time with no TFT assigned to it. Every PDP context exists independently in one of two PDP states. The PDP state indicates whether data transfer is enabled for that PDP address and TFT or not. In case all PDP contexts associated with the same PDP address are deactivated, data transfer for that PDP address is disabled. Activation and deactivation are described in clause "PDP Context Activation, Modification, Deactivation, and Preservation Functions". All PDP contexts of a subscriber are associated with the same MM context for the IMSI of that subscriber.

9.1.1 INACTIVE State

The INACTIVE state characterises the data service for a certain PDP address of the subscriber as not activated. The PDP context contains no routeing or mapping information to process PDP PDUs related to that PDP address. No data can be transferred. A changing location of a subscriber causes no update for the PDP context in INACTIVE state even if the subscriber is GPRS-attached.

Mobile-terminated PDP PDUs received in INACTIVE state by the GGSN may initiate the Network-Requested PDP Context Activation procedure if the GGSN is allowed to initiate the activation of the PDP context for that PDP address. Otherwise, mobile-terminated PDP PDUs received in INACTIVE state invoke error procedures in the P‑GW or GGSN relevant to the packet data network protocol, for example, an IP packet is discarded and an ICMP (see RFC 792 [41]) packet (error notification) is returned to the source of the received packet. Other error procedures may be introduced on the application level, but this is outside the scope of the present document.

The MS initiates the movement from INACTIVE to ACTIVE state by initiating the PDP Context Activation procedure.

9.1.2 ACTIVE State

In ACTIVE state, the PDP context for the PDP address in use is activated in the MS, SGSN and GGSN when using Gn/Gp, or in the MS, SGSN, S‑GW and P‑GW when using S4. The PDP context contains mapping and routeing information for transferring PDP PDUs for that particular PDP address between the MS and the P‑GW or GGSN. The PDP state ACTIVE is permitted only when the mobility management state of the subscriber is STANDBY, READY, PMM‑IDLE, or PMM‑CONNECTED. The Iu interface radio access bearer may or may not be established for an active PDP context.

An active PDP context for an MS is moved to INACTIVE state when the deactivation procedure is initiated.

All active PDP contexts for an MS are moved to INACTIVE state when the MM state changes to IDLE or PMM‑DETACHED.

Figure 61: Functional PDP State Model