Session Logic and Timing Challenges

Problem Statement

Session logic in multiplayer games often requires timeouts and delays for gameplay mechanics. For example, in a turn-based game, a round should resolve automatically after 30 seconds. In centralized applications, this is handled using threads that trigger timeouts. However, in a decentralized network, where session logic runs in parallel across multiple nodes, timing discrepancies arise due to:

• Diverging states across nodes when state-changing events arrive close to a timeout trigger.

• Lack of a global synchronized clock, making event ordering inconsistent.

A robust mechanism is needed to ensure deterministic execution of logic across all nodes while maintaining decentralization.

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Proposed Solution

In the decentralized network design, a central coordinating actor, called the Coordinator, organizes the network and acts as the primary point of interaction for clients.

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Coordinator Responsibilities

• Ensures timely responses to client requests.

• Triggers timeouts and propagates messages through a ring topology.

• Works with Witness nodes, which confirm events via double validation.

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Ring-Based Request Propagation

• Each request is sent through a ring structure to ensure redundancy and robustness.

• Witness nodes validate requests by ensuring they arrive from both directions before committing them.

• Similar to consensus protocols in distributed systems, this method ensures agreement across nodes.

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Coordinator Selection and Timeouts

• The initial Coordinator is randomly selected but will later be based on a trust score for reliability.

• The Coordinator is responsible for triggering all timeouts.

• Witness nodes do not trigger timeouts independently; they rely on timeout messages from the Coordinator.

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Handling Conflicts and State Synchronization

If a session logic timeout occurs, the network follows this process:

1. Coordinator triggers a timeout and propagates a message to all Witness nodes.

2. Clients may send state-changing requests that should cancel the timeout.

3. Witness nodes apply a double confirmation mechanism to ensure a valid timeout decision:

   • If a conflicting request is detected, the timeout is canceled.

   • Otherwise, the timeout is executed, and its result is added to the session proof.

4. Coordinator drops any late-arriving conflicting requests to prevent state inconsistency.

Witness nodes ensure that incorrect requests are filtered out:

• If a request arrives after a timeout is triggered, the Witness drops it.

• A redundant mechanism ensures incorrect requests do not receive validation from the ring topology.