The technical specifications for mobile systems — RAN, core, services and their management — and where they meet TM Forum's business and IT frameworks.
The 3rd Generation Partnership Project is where mobile networks are specified. It is a partnership of seven national and regional standards bodies (ETSI among them) rather than a body in its own right, and it publishes technical specifications in numbered Releases — Release 15 introduced 5G, Release 18 is 5G-Advanced — across three technical specification groups: RAN (the radio), SA (services and system aspects, including the core network architecture, security, and management), and CT (core network protocols and terminals). When a vendor says a base station or a 5G core is "compliant", it means compliant with these documents.
3GPP and TM Forum are often set side by side, and the contrast is real but easy to overdraw. TM Forum addresses how a service provider runs as a business and as an IT estate: processes (eTOM), information (SID), functions, APIs and the ODA architecture, for any kind of operator. 3GPP addresses how a mobile system works: radio access, core network, services and their management, in enough technical detail that equipment from different vendors interoperates. They meet in two places, both owned by 3GPP's SA5 working group. The first is charging: the TS 32.2xx series defines the charging architecture and the CHF (TS 32.290/291) that an online or converged charging system implements — the boundary billing systems described by TM Forum sit directly on. The second is the management of the network: SA5 specifies the management and orchestration interfaces of the network (the TS 28-series: network resource models, performance and fault management, slicing management), and that is precisely the boundary where ROM, inventory and assurance systems described by TM Forum have to talk to the network described by 3GPP.
3GPP·Network standard
3GPP specifications
What is it?
The technical specifications for mobile telecommunications systems — radio access (RAN), core network and services, and their management — produced by the 3rd Generation Partnership Project and published in numbered Releases. GSM, UMTS, LTE and 5G are all 3GPP systems; "Release 15" is where 5G begins.
What problem does it solve?
Makes a phone from one vendor work on a network built from another's equipment, in any country, and lets operators build networks from multi-vendor components.
What does it cover?
•Radio access: air interface, base station behaviour, spectrum use
•Core network: architecture, session and mobility management, policy and charging (the 5G core is service-based)
•Services and system aspects, including security
•Management and orchestration of the network (the TS 28-series), which is where 3GPP meets OSS
What does it NOT cover?
•Does not define customer, product or order concepts — those are TM Forum's; it is not a BSS operating model.
•Does not specify fixed access or optical transport technologies — those are ITU-T, IEEE and Broadband Forum territory — though since Release 16 it defines how wireline access attaches to the 5G core.
Where does it fit?
ServiceNetworkInfrastructureNetworkOSSOperations
When would an architect use this?
•Network architecture and technology roadmap decisions
•Designing OSS integration with the mobile core and RAN, including management interfaces
•Understanding which network capabilities can be exposed as APIs, and from where
•Reading a vendor's compliance statement for a network function
A specification number tells you where it lives: TS 23.xxx are stage-2 architecture documents (23.501 is the 5G system architecture), TS 29.xxx the protocol details, TS 38.xxx the 5G radio, TS 28.xxx management and orchestration. "TS" is a technical specification, "TR" a technical report — informative, not normative. Releases are frozen, so "Rel-17 feature" has a precise meaning.