Module 4 - Workflow

Understanding cross-chain Requests & Acknowledgment

Now that we Understand the Primary Characteristics of the Router Chain as an Interoperability Solution, let’s examine the Overall Lifecycle of passing a cross-chain request via the Router Chain and receiving an acknowledgment back on the Source Chain.

Generating and Sending a cross-chain Request

The Below steps Outlines the process of Generating and Sending a cross-chain request using Router Protocol -

1. Initiating cross-chain Action: A User triggers a cross-chain action on a Source Chain’s application Smart Contract, which then Calls the iSend() function on the Router Gateway Contract.

2. Event Emission: The Gateway Contract emits an Event on the Source Chain, which is picked up by Orchestrators on the Router Chain.

3. Fee Deduction: After Validating the event, the Router Chain Deducts a fee from the feePayerAddress associated with the dApp on the Router Chain.

4. Request Sent to Bridge Contract: The request is sent to the application’s Bridge Contract on the Router Chain, where the Source Contract address is Validated and Custom Logic is applied.

5. Request Execution:

   • If the Router Chain is the Destination Chain, the Bridge Contract executes the relevant functions and Terminates the request.
   • If an External Chain is the Destination Chain, the Bridge Contract generates an Outgoing request and pays the fees for the Transfer.
   • Any excess fees are refunded to the feePayerAddress.

6. Outgoing Request Validation: After the Transaction is mined on the Router Chain, the Outgoing request is Validated by the Orchestrators.

7. Event Forwarding: A Relayer forwards the Validated request to the Router Gateway Contract on the Destination Chain.

8. Receiving and Acting on Data: The Gateway Contract on the Destination Chain Calls the iReceive() function on the Destination Chain’s application Contract, which then acts on the Transferred Data.

Note: If there is no need for application-specific Bridging Logic, the application can use Router’s CrossTalk Framework to Integrate cross-chain functionalities with minimal Changes to its Codebase.

Generating and Sending an Acknowledgment

The Below steps Outlines the process of Generating and Sending an acknowledgment in a cross-chain request using Router Protocol -

1. Emit Acknowledgment Event: After the iReceive() function Completes on the Destination Chain, the Gateway Contract on that Chain emits an acknowledgment Event. This event is Detected by Orchestrators on the Router Chain.

2. Process Acknowledgment on Router Chain:

   • Transfer (RelayerIncentive + FeeConsumed) to the relayer address.
   • Refund (OutgoingTxFee - FeeConsumed) to the Bridge Contract on the Router Chain.

3. Send Acknowledgment to Bridge Contract: The Processed acknowledgment is Sent to the application’s Bridge Contract on the Router Chain.

4. Forward or Discard Acknowledgment:

   • If the dApp has requested the acknowledgment to be Sent back to the Source Chain, relayers forward it to the Source Chain’s Gateway Contract.
   • If not, the acknowledgment is Discarded.

5. Final Acknowledgment Delivery: The Gateway Contract on the Source Chain sends the acknowledgment to the application’s Contract on the Source Chain.