Product: RBC_GP, the Generic Platform of the reference RBC (repository RBC_GP). Layer: Generic Platform, above Platform_RTE and below RBC_GA. Language: C99 (vital A/B paths), C and C++ for role C. Assessment unit: Generic Product (RBC), see ../../docs/safety/CERTIFICATION_PLAN.dox.

Responsibility

The RBC executable that hosts the railway logic on the Safe Computing Platform:

ERTMS procedure engine: train sessions, train data, Movement Authority, position reports, shunting, emergency stop, end of mission, temporary speed restrictions, handover, text messages (Subset-026 procedures).
Route and train database and the MA logic gate, the only path that connects a route to a train and grants Movement Authority.
2oo2 redundancy of channels A and B: per-cycle cross-compare of the session table, checkpoint stage, staged sends that are committed or discarded by the checkpoint result, and the reaction (reboot) when A and B disagree on the site role.
Site redundancy: GP is the Site Role Client of Platform_RTE's site-role service (rte_site_role, ADR-040), which negotiates ONLINE/STANDBY with the other site: GP agrees the startup timestamp between A and B, hands the service its local facts and the sibling's site state, and transfers sessions and database to the promoted site. Redundancy topology and channel definitions come from etc/config/<role>_<site>.json; GP registers the topology it supports.
Role C gateways (non-vital): per-domain relay processes (train, IL, CTC, status) between the outside world and A/B.
Hosting GA: GP loads RBC_GA and gives it route and train context.

It does not own signalling adaptation logic (RBC_GA), site topology data (RBC_SA), the OS or transport OSAdapters (Platform_OS_POSIX, Platform_Protocol_*), or voting and safe-state mechanisms (Platform_RTE).

Processes: rte_example <A|B> <WEST|EAST> (A/B, a thin launcher over librte_gp) and rte_gateway_c_{train,il,ctc,status} <WEST|EAST> (role C). The IL and CTC gateway binaries are built by RBC_GA and installed next to the others.

Interfaces exposed to other products

Interface	Form	Consumed by	Notes
GA interface src/application/AB/GP/ga_interface/ga_interface.h	C header: one init call declared for GA, callback registration, route and train context snapshots and pulls, validated setters	RBC_GA	The assessed GP/GA boundary; versioned
Site contract include/ab_siteGP.h	Full RailML-aligned topology header	RBC_SA implements it as sa::site::gp
RBC wire protocol src/application/AB/common/rbc_wire_types.h (rbc_envelope_t, 512 bytes; one copy, shared by roles A/B and C)	Byte layout, encoded per domain	RBC_Test_Sim_*, RBC_Test_CommServer, RBC_GA	Python mirror in RBC_Test_Sim_Core/rbc_wire.py; update both together
Interface control documents	interfaces/rbc_train_interface.dox, rbc_il_interface.dox, ctc_rbc_interface.dox	Integrators, simulators	Target ERTMS specification versus the simplified testbed protocol
Logical channels	ab-peer, ab-crosscompare, ab-relay-{train,il,ctc,util}	Configuration	Bound to transports by configuration. Exception: the inter-site link is opened by rte_site_role on the compiled ports RTE_EXAMPLE_{A,B}_NEGOTIATION_PORT; the ab-negotiate entry in the JSON files is not used to open it
Configuration	etc/config/.conf, etc/config/.json, RTE_CONFIG_FILE and RTE_REDUNDANCY_CONFIG_FILE (fallback etc/config/redundancy.json), RTE_RBC_LOG_LEVEL, RTE_EXAMPLE_* environment variables	Deployment, RBC_Test_Env	Ports in .conf files must match common_config.h; see ISSUES.dox
Binaries and libraries	dist/<platform>/bin, lib/librte_gp, lib/librte_rbc2oo2_ga	RBC_SA installers	GA and GP libraries must be installed together

Interfaces required

Needs	From	How
Flow, app manager, voter, cross-comparator, checkpoint, site-role service and dual negotiator, state transfer, redundancy config, safe state	Platform_RTE	rte::* targets
OSAdapter registration	Platform_OS_POSIX	Composition root only
Flow OSAdapter	Platform_Protocol_DDS (stub)	Registered in ab_gp_channel.c
Site tables	RBC_SA	sa::site::gp
Signalling logic	RBC_GA	Shared library, add_subdirectory() by default

Build and test

cmake -S . -B build          # finds platform/Platform_RTE and its siblings by the workspace layout
cmake --build build && ctest --test-dir build --output-on-failure
cmake --install build --prefix .           # dist/<platform>/{bin,lib}
.claude/skills/run-RBC_GP/smoke.sh 15      # 8-process live scenario: core checks and failover

The full stack (Docker Compose, Robot Framework, simulators) is built and run from test/RBC_Test_Env.

Where to read next

Working notes, rules and gotchas: CLAUDE.md
ONLINE/STANDBY negotiation, A/B agreement and cross-comparison, end to end: docs/STANDBY_AND_SITE_LINK_ARCHITECTURE.dox
Reference design narrative (partly historical): docs/REFERENCE_DESIGN.dox
ERTMS logic: docs/ERTMS_LOGIC_SPECIFICATION.dox; timing and data loss: docs/TIMING_AND_DATA_LOSS_ANALYSIS.dox
MISRA deviations (vital A/B <stdio.h>/<stdlib.h> use): docs/MISRA_COMPLIANCE_REPORT.dox
Workspace context: ../../docs/architecture/OVERVIEW.dox