S6b AVPs

S6b (application id: 16777272)

The S6b interface is a key component in the architecture of the Diameter protocol, specifically designed to facilitate communication between the 3GPP AAA Server and the Packet Data Network Gateway (PDN-GW) within the Evolved Packet Core (EPC) of a mobile network. The primary purpose of the S6b interface is to support the authentication, authorization, and mobility management of User Equipment (UE) accessing the network via non-3GPP access technologies such as Wi-Fi.

S6b interface workflow:

UE Attachment:

• When a UE connects to the EPC via a non-3GPP access network (e.g., using the S2a or S2b reference point), it initiates a connection request. This request is forwarded by the PDN-GW to the 3GPP AAA Server over the S6b interface for authentication and authorization.

Authentication and Authorization:

• The 3GPP AAA Server authenticates the UE using protocols such as EAP-AKA over IKEv2. Once the UE is successfully authenticated, the AAA Server authorizes the session, allowing the UE to access network resources.

Session Management:

• Upon successful authentication, the PDN-GW updates its session information to reflect the UE’s current status, IP address, and other relevant data. The S6b interface facilitates this information exchange, ensuring that the PDN-GW has the latest data to manage the UE’s session effectively.

Mobility Handling:

• As the UE moves between different access points or networks, the S6b interface is used to update the PDN-GW with new location and session parameters. This ensures that the UE can maintain an ongoing session without interruption, even as it changes its point of attachment to the network.

QoS and Resource Management:

• Throughout the session, the S6b interface is used to dynamically adjust QoS parameters based on the UE’s needs and network conditions. This allows the network to provide the best possible service to the UE while managing overall network resources efficiently.

Accounting and Reporting:

• The S6b interface ensures that all relevant data usage is accurately recorded and reported to the service provider’s billing systems. This is essential for accurate billing and for providing users with detailed information about their data usage.

Session Termination:

• When the UE disconnects or the session is otherwise terminated, the S6b interface is used to properly close the session, releasing any resources that were allocated to the UE.

For complete technical specification of S6b interface in Diameter protocol please refer to: [3GPP TS 29.273]

package com.mobius.software.telco.protocols.diameter.primitives.s6b;