RFC Gap: Room protocol remaining details (port allocation, game message payloads, NPS-MCOTS integration)

[drazisil]

Summary

Follow-up to #2805. The docs/room-game-server-protocol.md file addresses most room protocol questions, but a few details remain undocumented.

Remaining Gaps

1. Port Allocation Algorithm

Current state: Section 13 note 2 says "port selection is server-side" but doesn't specify the algorithm.

Questions:

• How does the server decide which port (9000-9014) to assign for a new game server?
• Is it round-robin, first-available, or based on some other criteria?
• What happens when all ports are in use?

2. In-Race Game Message Payloads (0x80-0x87)

Current state: Section 3 lists the game message opcodes but not their payload structures.

Opcode	Name	Payload Structure
0x80	NPS_SEND_ALL	?
0x82	NPS_SEND_GAME_READY_LIST	?
0x83	NPS_SEND_LIST	?
0x86	NPS_SEND_SINGLE	?
0x87	NPS_SEND_NOT_SINGLE	?

Questions:

• What is the payload format for each message type?
• How is game state (position, speed, collisions) encoded?
• What's the difference between TCP (channel 0) and UDP (channel 1) message contents?

3. NPS-MCOTS Integration

Current state: The room protocol doc covers NPS flow. The RFC covers MCOTS race flow. The integration between them is unclear.

Questions:

• When a player sends MC_RACE_JOIN (218) on port 43300, does this trigger any NPS room activity?
• Does MC_RACE_START (232) on MCOTS trigger NPS_START_GAME_SERVER (0x10A) on NPS, or are they independent?
• Is the race password from MC_RACE_CREATE_OK (223) the same password used in NPS_OPEN_COMM_CHANNEL (0x106)?
• What's the sequencing between MCOTS and NPS messages during race setup?

Priority

These gaps are lower priority than the main room protocol documentation. They may become blocking during implementation of:

• Multi-player race synchronization
• In-race position/state updates
• Complete race lifecycle

Related Files

• docs/room-game-server-protocol.md - Room protocol documentation
• docs/MCO_PROTOCOL_RFC.md - MCOTS protocol documentation
• packages/lobby/src/handlers/handleStartGameServer.ts - Game server start (stub)

Related Issues

• Closes gap identified in RFC Gap: Document room/game server protocol (ports 9000-9020) and race integration #2805