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@@ -1,6 +1,189 @@
# Vendor Extensibility
+Mechanism for the APIs to re-use, extend their functionalities and data models and engage with third-party API frameworks (e.g. ETSI MEC)
+
+Vendor specific extensions are defined on 3GPP TS 29.122 (section 5.2.13) and 29.500 (section 6.6.3) and is tightly connected with "supported-features†and "feature negotiation" procedures.
+
+## Vendor Extensibility in CAPIF:
+Vendor Extensibility is a feature focused on the APIs that are published and exposed via CAPIF.
+As a result, the feature is supported by the ServiceAPIDescription object (and any other objects embeded on it e.g. AefProfile). In the figure below, depicting all supported features of ServiceAPIDescription,
+VendExt feature is noted, which enables vendor-specific extension in the body of the specific object.
+
+
+
+Vendor extensibility feature can be enabled and leveraged in 2 CAPIF APIs, Publish and Discover.
+
+## Vendor Extensibility in CAPIF APIs
+
+### Publish API
+A vendor can extend the ServiceAPIDescription object by adding additional member elements. However, in order to avoid duplication of member names inside a same object
+it is necessary to comply with a naming scheme for vendor-specific data elements, to avoid clashing names between vendors.
+Vendor-specific member names in JSON objects shall be named in the following manner:
+```
+ "vendorSpecific-nnnnnnnnn": {
+ ...
+ }
+```
+
+where the value "nnnnnn" can be:
+
+1. 6-digit IANA-assigned enterprise code:
+
+```
+ "vendorSpecific-010415": {
+ ...
+ }
+```
+
+2. domain name:
+
+
+```
+"vendorSpecific-3gpp.org": {
+ ...
+ }
+```
+
+3. URN:
+
+
+```
+"vendorSpecific-urn:3gpp:example": {
+ ...
+ }
+```
+
+A concrete example of vendor-specific extensibility exists on section 9 of ETSI GS MEC 011 V3.2.1, where ETSI MEC extends the ServiceAPIDescription as depicted on the following two figures.
+
+
+
+
+
+**Example:**
+
+ServiceAPIDescription vendorSpecific looks like:
+
+```json
+"vendorSpecific-urn:etsi:mec:capifext:service-info": {
+ "serializer": "JSON",
+ "state": "ACTIVE",
+ "scopeOfLocality": "MEC_SYSTEM",
+ "consumedLocalOnly": "True",
+ "isLocal": "True",
+ "category": {
+ "href": "https://www.location.com",
+ "id": "location_1",
+ "name": "Location",
+ "version": "1.0"
+ }
+}
+```
+
+AEFProfile vendorSpecific looks like:
+
+```json
+"vendorSpecific-urn:etsi:mec:capifext:transport-info": {
+ "name": "trasport1",
+ "description": "Transport Info 1",
+ "type": "REST_HTTP",
+ "protocol": "HTTP",
+ "version": "2",
+ "security": {
+ "grantTypes": "OAUTH2_CLIENT_CREDENTIALS",
+ "tokenEndpoint": "https://token-endpoint/"
+ }
+}
+```
+
+Complete ETSI MEC ServiceAPIDescription with vendor extensibility would be like this:
+
+```json
+{
+ "apiName": "service_1",
+ "vendorSpecific-urn:etsi:mec:capifext:service-info": {
+ "serializer": "JSON",
+ "state": "ACTIVE",
+ "scopeOfLocality": "MEC_SYSTEM",
+ "consumedLocalOnly": "True",
+ "isLocal": "True",
+ "category": {
+ "href": "https://www.location.com",
+ "id": "location_1",
+ "name": "Location",
+ "version": "1.0"
+ }
+ },
+ "aefProfiles": [
+ {
+ "aefId": "string",
+ "vendorSpecific-urn:etsi:mec:capifext:transport-info": {
+ "name": "trasport1",
+ "description": "Transport Info 1",
+ "type": "REST_HTTP",
+ "protocol": "HTTP",
+ "version": "2",
+ "security": {
+ "grantTypes": "OAUTH2_CLIENT_CREDENTIALS",
+ "tokenEndpoint": "https://token-endpoint/"
+ }
+ },
+ "versions": [
+ {}
+ ],
+ "protocol": "HTTP_1_1",
+ "dataFormat": "JSON",
+ "securityMethods": ["PSK"],
+ "interfaceDescriptions": [
+ {
+ "ipv4Addr": "string",
+ "port": 65535,
+ "securityMethods": ["PSK"]
+ }
+ ]
+ }
+ ],
+ "description": "string",
+ "supportedFeatures": "0",
+ "shareableInfo": {
+ "isShareable": true,
+ "capifProvDoms": [
+ "string"
+ ]
+ },
+ "serviceAPICategory": "string",
+ "apiSuppFeats": "fffff",
+ "pubApiPath": {
+ "ccfIds": [
+ "string"
+ ]
+ },
+ "ccfId": "string"
+}
+```
+
+### Discover API
+
+In order to use vendor-specific fields as filters in Discover API, vendor-specific query parameter shall be encoded as follows:
+
+```json
+https://{{CAPIF_HOSTNAME}}:{{CAPIF_PORT}}/{{DISCOVER_URL}}?
+ ...
+ vend-spec-<query parameter name>={
+ "target": <string that contains the JSON pointer to the attribute in the resource representation>,
+ "value": <query parameter value>
+}
+```
+
+**Example:**
+```json
+ https://{{CAPIF_HOSTNAME}}:{{CAPIF_PORT}}/{{DISCOVER_URL}}?
+ ...
+ vend-spec-type={
+ "target": "/vendorSpecific-urn:etsi:mec:capifext:transport-info",
+ "value": "REST_HTTP"
+ }
+```
+
-DOC:Work in Progress
[OCF Web]: https://ocf.etsi.org/ "OCF Web"