Vertical Application Layer Group Member

Description

A VAL group member is an individual VAL service user who is included in a VAL group's membership list, identified by their unique VAL user ID. This concept is central to the 3GPP Vertical Application Layer (VAL) architecture, introduced in Release 19, as it defines who can participate in group-based services and communications. Membership in a VAL group is typically managed by the group's home system, which maintains the authoritative list of members and their associated permissions.

The VAL user ID is a unique identifier assigned to each VAL service user within the VAL system. When a user is added to a VAL group, their VAL user ID is recorded in the group's membership list. This allows the network to authenticate and authorize the user for group services, such as group calls, group messaging, and group data sharing. The membership list may also include additional attributes, such as roles, priorities, or expiration times, depending on the service requirements.

From an architectural perspective, the VAL group member interacts with the VAL server to access group services. The VAL server validates the user's membership by checking the group's home system and then grants access to the requested service. The member may also receive notifications about group activities, such as new members joining or group policy changes. The membership status can be static (pre-provisioned) or dynamic (added on demand), and can be modified by authorized administrators or through automated procedures.

The VAL group member concept also has implications for security and privacy. The home system enforces access control, ensuring that only authorized users can join or remain in the group. It may also manage encryption keys for secure group communication, ensuring that only members can decrypt group messages. The membership list is protected against unauthorized access and modification.

In terms of standardization, the VAL group member is defined in 3GPP TS 23.434 and TS 29.549. These specifications outline the procedures for managing group membership, including adding, removing, and querying members. The concept has been carried forward unchanged into Release 20, reflecting its foundational role in the VAL framework.

Purpose & Motivation

The VAL group member concept was created to provide a clear and standardized way to identify and manage participants in VAL group services. Prior to Release 19, vertical applications often used proprietary or ad-hoc methods to manage group membership, leading to interoperability issues and management complexity. A standardized definition of a group member, based on a unique VAL user ID, enables consistent authentication, authorization, and policy enforcement across different systems and vendors.

The VAL group member abstraction allows the network to treat each participant as a distinct entity with specific rights and privileges within the group. This is essential for services that require differentiated treatment, such as priority users in emergency response or role-based access in industrial settings. It also simplifies charging and billing, as group services can be billed per member or based on member-specific usage.

Furthermore, the VAL group member concept supports scalability and flexibility. Groups can have many members, and members can belong to multiple groups simultaneously. The home system manages these relationships efficiently, ensuring that membership changes are propagated correctly. The introduction in Release 19 reflects the need for a robust and interoperable group management framework in the VAL architecture, addressing the limitations of previous approaches.