Enable xApp to:

• Send messages
• Access R-NIB and database
• Talk to eNBs and gNBs
• Define life-cycle
• Report logs and status

Help developers:

• Generate skeleton codes
• Setup development and testing environments
• Package, distribute and onboard their xApp

• Libraries, Interfaces and APIs
• Tools
• Documentation and Guides
• Code Samples
• Processes and Flows

R-NIB:

• Inventory of RAN elements connected to the O-RAN SC
• Service models (SMs) supported by each RAN element
• …

Note: Load balanced connection management via replicated E2 Terms.

Other NIBs store UE-level metrics and aggregate metrics.

E2:

• Available E2SMs populated in R-NIB (in R5)
• xApp constructs E2AP/SM message contents and sends/receives via RMR
• RMR will route subscription requests to SubManager (for policy checking) and all messages to the correct E2T instance. (now)
• REST-based subscription API (in R5)

A1:

• Policy definition happens outside O-RAN SC
• xApp specifies supported policy types in xApp descriptor
• xApp receives policy instance creation/deletion via RMR
• Frameworks: ”register handler for A1” (now)

O1-CM:

• Initial and updated configuration via K8s config map
• We believe this can be abstracted by the framework (xApp just registers a handler)
• Still open discussion in O-RAN WGs on how LCM should be done.

O1-PM/FM:

• xApp alarm api partially available in R4 (go only), stat api in R5.
• (for now) AT&T xApps use VES, Nokia xApps use Prometheus.

Policy driven messaging

C++, Python, Go

Yes

RIC Message Router – RMR

 shared data storage

C++, Go

Yes

O-RAN SC SDL C++ library User Guide

Logging

C/C++, Python, Go

Yes

Alarm Propagation

C++, Go

RIC Alarm System

Tracing

C++, Go

xAppFramework

Wrappers

C++, Python, Go

Yes

RIC xAPP C++ Framework

• RMR Guides

  • Developer Documentation
  • RIC Message Router (RMR) (wiki)

• SDL Guide

• xAppFramework Guide

• xApp Writing Guide

• xApp Architecutre, Models and Assumptions

• ASN.1 User Guide