# CCIP Router Setup Guide

## Overview

This guide explains how to set up and deploy the Chainlink CCIP Router for cross-chain oracle updates.

## Prerequisites

- Chainlink CCIP Router contract deployed on source and target chains
- LINK tokens for paying CCIP fees
- Access to deploy contracts
- Validator keys for signing transactions

## Deployment Steps

### Step 1: Get CCIP Router Addresses

CCIP Router addresses vary by chain:

- **Ethereum Mainnet**: `0x80226fc0Ee2b096224EeAc085Bb9a8cba1146f7D`
- **Polygon**: `0x3C3D92629A02a8D95D5CB9650fe49C3544f69B43`
- **Avalanche**: `0xF694E193200268f9a4868e4Aa017A0118C9a8177`
- **Arbitrum**: `0x1619DE6B6B20eD217a58d00f37B9d47C7663feca`
- **Optimism**: `0x261c05167db67Be2E2dc4a347C4E6B000C677852`

For ChainID 138, deploy a custom CCIP Router or use a compatible implementation.

### Step 2: Deploy CCIP Router (if needed)

If deploying a custom CCIP Router:

```bash
# Deploy CCIP Router
forge script script/DeployCCIPRouter.s.sol --rpc-url $RPC_URL --broadcast
```

### Step 3: Configure Router Address

Update contract configurations:

```solidity
// In CCIPSender.sol
address public constant CCIP_ROUTER = 0x...; // Your router address

// In CCIPReceiver.sol
constructor(address _router, address _oracleAggregator) {
    router = IRouterClient(_router);
    // ...
}
```

### Step 4: Set Chain Selectors

Configure chain selectors for target chains:

```solidity
// Chain selectors
uint64 constant ETHEREUM_MAINNET = 5009297550715157269;
uint64 constant POLYGON = 4051577828743386545;
uint64 constant AVALANCHE = 6433500567565415381;
uint64 constant ARBITRUM = 4949039107694359620;
uint64 constant OPTIMISM = 3734403246176062136;
```

### Step 5: Fund LINK Tokens

Ensure contracts have sufficient LINK tokens for fees:

```bash
# Transfer LINK to sender contract
cast send $SENDER_CONTRACT "transfer(address,uint256)" $LINK_TOKEN $AMOUNT --rpc-url $RPC_URL --private-key $PRIVATE_KEY
```

### Step 6: Verify Deployment

```bash
# Check router address
cast call $SENDER_CONTRACT "router()" --rpc-url $RPC_URL

# Check chain selector
cast call $SENDER_CONTRACT "targetChainSelector()" --rpc-url $RPC_URL
```

## Configuration Files

### Kubernetes Deployment

Deploy CCIP Router service (if running as a service):

```yaml
# k8s/ccip/router-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ccip-router
  namespace: besu-network
spec:
  replicas: 1
  selector:
    matchLabels:
      app: ccip-router
  template:
    metadata:
      labels:
        app: ccip-router
    spec:
      containers:
        - name: ccip-router
          image: chainlink/ccip-router:v1.0.0
          env:
            - name: RPC_URL
              value: "http://besu-rpc:8545"
            - name: PRIVATE_KEY
              valueFrom:
                secretKeyRef:
                  name: ccip-router-secrets
                  key: private_key
```

### Environment Variables

```bash
# .env
CCIP_ROUTER_ADDRESS=0x...
TARGET_CHAIN_SELECTOR=5009297550715157269
LINK_TOKEN_ADDRESS=0x...
```

## Testing

### Test CCIP Router Connection

```bash
# Test router is accessible
cast call $CCIP_ROUTER "getSupportedTokens(uint64)" $CHAIN_SELECTOR --rpc-url $RPC_URL
```

### Test Message Sending

```bash
# Send test message
forge script script/TestCCIPSend.s.sol --rpc-url $RPC_URL --broadcast
```

## Monitoring

Monitor CCIP Router health:

- Router availability
- Message processing rate
- Fee consumption
- Error rates

See `monitoring/prometheus/alerts/ccip.yml` for alerting rules.

## Troubleshooting

### Router Not Found

1. Verify router address is correct
2. Check router is deployed on the chain
3. Verify network/chain ID matches

### Insufficient LINK

1. Check LINK balance
2. Transfer more LINK tokens
3. Monitor fee consumption

### Message Delivery Failures

1. Check target chain selector
2. Verify receiver contract address
3. Check target chain router is operational
4. Review error logs

## Security

1. **Access Control**: Restrict router configuration to authorized addresses
2. **Fee Limits**: Set maximum fee limits to prevent excessive spending
3. **Rate Limiting**: Implement rate limiting for message sending
4. **Monitoring**: Monitor for unusual activity

## References

- [Chainlink CCIP Documentation](https://docs.chain.link/ccip)
- [CCIP Integration Guide](docs/CCIP_INTEGRATION.md)
- [CCIP Message Format](docs/CCIP_MESSAGE_FORMAT.md)