PDN Update Procedure - eNodeB F-TEIDu

Feature Description

For S-GW or SAEGW, a procedure to initiate an N4/Sx Modification Request is implemented for:

  • eNodeB F-TEIDu update

  • Release Access Bearer (RAB) Request for an eNodeB release

How it Works

The PDN update procedure includes the following events for an eNodeB F-TEIDu Update/Release:

  • For eNodeB F-TEIDu Update:

    1. The SGW-C initiates N4/Sx Session Modification Request toward SGW-U on receiving a Modify Bearer Request for eNodeB F-TEIDu Update from the MME.

    2. The N4/Sx Modification Request for eNodeB F-TEIDu update contains Update FAR with Apply Action as “Forward” and the updated eNodeB IPv4/IPv6 address in Outer Header Creation, which is a part of the Update Forwarding Parameters IE.

  • For eNodeB F-TEIDu Release:

    1. The SGW-C initiates N4/Sx Modification Request toward SGW-U on receiving a RAB Request from the MME.

    2. RAB is a UE-level message. If the UE has multiple PDN connections, then the N4/Sx Modification Request is sent to each PDN connection separately.

    3. SGW-C initiates N4/Sx Session Modification Request toward SGW-U for the N4/Sx session with Update FAR with destination interface as ACCESS. Update FAR contains: FAR ID and Apply Action as Drop. FAR with the destination interface as CORE is not updated.

Standards Compliance

The PDN Update procedure complies with the following standards:

  • 3GPP TS 23.401: "General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access".

  • 3GPP TS 29.274: "3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunnelling Protocol for control plane (GTPv2-C); Stage 3".

  • 3GPP TS 29.244: “Interface between the Control Plane and the User Plane of EPC ".

  • 3GPP TS 23.214: "Architecture enhancements for control and user plane separation of EPC nodes; Stage 2"

  • 3GPP TS 23.714: "Study on control and user plane separation of EPC nodes"