> For the complete documentation index, see [llms.txt](https://docs.novastro.xyz/novastro_chain/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.novastro.xyz/novastro_chain/products-and-ecosystem/chain-router.md).

# Chain Router

Novastro’s **Cross-Chain Bridge & Messaging Hub** is the behind-the-scenes engine that allows Novastro-issued tokens (DTC-based RWA tokens) to flow frictionlessly between Ethereum (issuance layer) & Arbitrum, Solana, Sui, and other supported ecosystems (trading layer). 

### What Is It?

The Cross-Chain Bridge & Messaging Hub is a foundational Novastro module that:

* Handles interoperability between multiple blockchains
* Uses trusted, secure third-party bridges (Wormhole, LayerZero, Axelar)
* Manages token transfers, fee payments, and chain-specific logic
* Enables RWA tokens to function multichain without worrying about infrastructure

The module comprises:

* Smart contracts deployed on Ethereum and supported destination chains
* Off-chain relayers/oracles that monitor events and pass messages
* A unified API/interface used by other Novastro components for sending/receiving tokens or data across chains

### How It Works (Step-by-Step)

**Example: Moving a Token from Ethereum to Solana**

1. **User Request Initiation**\
   The user initiates a transfer via Novastro’s interface—choosing to move a token from Ethereum to Solana.
2. **Token Locking (Ethereum Side)**\
   The bridge contract on Ethereum locks the original token in a vault. This ensures the total circulating supply remains secure and traceable.
3. **Message Relay**\
   An off-chain relayer or oracle picks up the event and communicates it to the Solana-side bridge contract via Wormhole, LayerZero, or Axelar.
4. **Token Minting (Solana Side)**\
   A corresponding wrapped token is minted on Solana, 1:1 matched with the locked token on Ethereum.
5. **User Receives Token on Solana**\
   The user now holds the same RWA token, but usable within the Solana ecosystem.
6. **Return Path (Solana to Ethereum)**\
   When moved back, the wrapped token is burned on Solana, and the original is unlocked on Ethereum.

### Fee Abstraction

Cross-chain transfers usually require native gas tokens on each chain. Novastro abstracts this complexity:

* **Users can pay fees in ETH, $NOVAS, or other supported tokens**
* The hub handles **gas conversion** and **pays the required fee** on the destination chain

Result: Users don’t need to keep wallets topped up with Solana, SUI, or ARB tokens.

### Why are We Using Third-Party Bridges?

Instead of building a custom bridge (which increases risk), Novastro leverages top-tier, audited networks:

* **Wormhole** – Used by many leading DeFi apps across Solana and Ethereum
* **LayerZero** – Known for ultra-fast messaging and minimal trust assumptions
* **Axelar** – Offers general message passing and secure asset transfers

This allows Novastro to focus on product innovation while relying on proven security for interoperability.