3 Definitions and abbreviations

29.5013GPP5G SystemPrinciples and Guidelines for Services DefinitionRelease 18Stage 3TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

3.1 Definitions

For the purposes of the present document, the terms and definitions given in 3GPP TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in 3GPP TR 21.905 [1].

Absolute URI: Absolute URI follows generic URI syntax and consists of a hierarchical sequence of the following components: the "scheme", "authority", "path" and "query", i.e. excluding the "fragment" component. See clause 4.3 in IETF RFC 3986 [9].

apiRoot: apiRoot follows an absolute URI syntax, but excludes the following absolute URI identifiers: the "query" and "fragment" components. The API root contains the "scheme" and the "authority" components and may also contain an API prefix subcomponent. See clause 4.4.1. In 3GPP APIs, the default apiRoot value is "https://example.com" (see e.g. Annex A.2 in 3GPP TS 29.502 [20]), where "example.com" is replaced by the operator specific FQDN (for FQDN examples see clause 28.3.2 in 3GPP TS 23.003 [27]).

API Prefix: API prefix is an optional, deployment-specific string, which is a subcomponent of the "apiRoot". API prefix format follows "path-absolute" syntax and that starts with a "/" reserved character (see clause 4.4.1and also clause 3.3 in IETF RFC 3986 [9]). In 3GPP APIs, the default apiRoot does not contain API Prefix (see e.g. Annex A.2 in 3GPP TS 29.502 [20]).

API URI: API URI has the following format: "{apiRoot}/<apiName>/<apiVersion>". For more details see clause 4.4.1. As an example, for the Nudm_SDM API defined in 3GPP TS 29.503 [28], the API URI is: "{apiRoot}/nudm-sdm/v2".

Base URI: Base URI is used as a reference against which the relative URI reference is applied. See clause 4.6.1.1.1.2 and also clause 5.1 in IETF RFC 3986 [9]. As an example, for the resource URI of the SM contexts collection that is defined in Nsmf_PDUSession API (see 3GPP TS 29.502 [20]), the base URI is "{apiRoot}/nsmf-pdusession/<apiVersion>".

Callback URI: Callback URI follows an absolute URI syntax, but excludes the following absolute URI identifiers: "userinfo" subcomponent of the "authority" component and also the "query" component ("fragment" component is already excluded from the absolute URI). Therefore, callback URI contains the "scheme", "authority" (excluding "userinfo" subcomponent) and the "path" components. See clause 4.4.3. As an example, for the Nsmf_PDUSession API defined in 3GPP TS 29.502 [20], "smContextStatusUri" is one of the callback references that can be provided by the NF Service Consumer. A complete callback URI for the "smContextStatusUri" has the following structure https://<comsumer-host>/<consumer-path-segment>/smContextStatus, where "consumer-host" is either an FQDN or an IP address (see clause 4.4.3).

Relative path after API URI: Refers to the sequence of path segments of a resource URI that are below the API URI (see the definition of the "Paths Object" in OpenAPI specification [4]). When appended to the API URI of the concerned API, it constitutes the resource URI. As an example, for the Nudm_SDM API defined in 3GPP TS 29.503 [28] for which the API URI is "{apiRoot}/nudm-sdm/v2", the "relative path after API URI" for the "AccessAndMobilitySubscriptionData" resource is: "/{supi}/am-data".

Relative URI: Relative URI is deprecated and shall not be use in SBI spcificationsSee clause 1.2.3 in IETF RFC 3986 [9].

Resource URI: Resource URI identifies an abstract or a physical resource. See the Abstract of the IETF RFC 3986 [9]. In this specification this generally means "an URI of a resource". Resource URI structure is defined in clause 4.4.1. As an example, for the resource URI of the SM contexts collection that is defined in Nsmf_PDUSession API (see 3GPP TS 29.502 [20]), the resource URI is "{apiRoot}/nsmf-pdusession/<apiVersion>/sm-contexts".

3.2 Abbreviations

For the purposes of the present document, the abbreviations given in 3GPP TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in 3GPP TR 21.905 [1].

5GC 5G Core Network

CNF Conjunctive Normal Form

CRUD Create, Read, Update, Delete

DNF Disjunctive Normal Form

HAL Hypertext Application Language

HATEOAS Hypermedia as the Engine of Application State

REST REpresentational State Transfer

RPC Remote-Procedure-Call

SBI Service Based Interface

YAML YAML Ain’t Markup Language

3.3 Special characters, operators and delimiters

3.3.1 General

A number of characters have special meaning and are used as delimiters in this document and also in other stage 3 SBI specifications. Below clauses specify the usage of a selected set of the special characters. Full set of these special characters are specified in the respective IETF specifications.

3.3.2 ABNF operators

Special characters that are used as delimiters in ABNF syntax have somewhat different purpose from the same characters when used by URI syntax. See clause 3.3.2 in 3GPP TS 29.500 [2].

3.3.3 URI reserved and special characters

/ Reserved character. The forward slash character is a delimiter, which precedes an URI path component and also separates a sequence of path segments. See clauses 2.2 and 3.3 in IETF RFC 3986 [9].

# Reserved character. The number sign (hash) character is a delimiter, which terminates either an URI path component, or an authority component, or a query component and starts a fragment component. See clauses 2.2, 3.2, 3.3 and 3.5 in IETF RFC 3986 [9].

? Reserved character. The question mark character is a delimiter, which terminates either an URI path component, or an authority component and starts a query component/parameter. See clauses 2.2, 3.2, 3.3 and 3.4 in IETF RFC 3986 [9].

= Reserved character. The equal sign character is a delimiter, which separates a parameter name and its value, e.g. in an URI query. See clauses 1.2.3 and 3.3 in IETF RFC 3986 [9].

[ ] Reserved character. The square bracket characters enclose an IPv6 literal address. This is the only place where square bracket characters are allowed in the URI syntax. See clause 3.2.2 in IETF RFC 3986 [9].

< > Special characters. The angle bracket characters are delimiters and enclose a complete URI or an URI component or a subcomponent. See Appendix C in IETF RFC 3986 [9].

; Reserved character. The semicolon character is a delimiter, which is often used to separates a parameter name and its value in a path segment. See clause 3.3 in IETF RFC 3986 [9].

: Reserved character. The colon character is a delimiter, which either terminates an URI scheme component, or userinfo subcomponent, or separates host subcomponent from the port subcomponent, an authority component, or a query component and starts a fragment component. See clauses 2.2, and 3.2 in IETF RFC 3986 [9].

NOTE: The same characters, like "/", "#", etc. lead to different processing in ABNF and URI grammars. For instance, in URI syntax, ";" character separates parameter and its value, while in ABNF ";" starts a comment.

3.3.4 SBI specific usage of delimiters

The braces (curly brackets) are used as delimiters across the SBI specifications, but have somewhat different purpose as specified below.

{ } Delimiters. The braces (curly brackets) characters enclose a name of a variable in an URI path segment (see clause 5.1.3.2). Example: …/subscriber-data/{supi}.

{ } Delimiters. The braces (curly brackets) characters enclose a parameter value in a query (see clause 5.1.3.3). Example: ?nf-id={chooseAValue}

NOTE: In SBI specifications, "< >" is a generic placeholder, while "{ }" enclose specifically a variable.