Understanding how different networks work on a technical level

Question

This is a weird question so bare with me:

• Assume I purchased some ETH from Coinbase and want to send it to a private wallet

  • This basically means that Coinbase, as a CEX, provided my off-chain Coinbase account some ETH in exchange for Euros. No idea if they actually have sent ETH to an on-chain account with private keys they own or not. The end goal is that they provided some ETH to me and I have control of it
  • This also means, in practice, that Coinbase has a (possibly) Geth P2P node running that sends a transaction signal using whatever Gossip protocol Ethereum uses to the Ethereum Mainnet network (i.e., all other Geth P2P nodes)

• Let's assume the account Coinbase sent money from is 0xAAA and my private wallet account is 0xBBB

• During the transaction, they asked "which network to use?". This is the confusing part for me: the Ethereum network is a collection of P2P nodes (most probably running Geth) that run the EVM and advance the state based on a consensus protocol. This means that for all Geth P2P nodes now have a new pending transaction (sending ETH from 0xAAA to 0xBBB) that needs to be put into a block by a validator chosen from the consensus algorithm.

The confusing part to me is this: how are different networks capable of understanding this? How can I send money to Polygon or Avalanche as well as Ethereum Mainnet?

The way I think this happens (and here's where I need clarification) is that there are P2P clients (running maybe Geth on Polygon/Avalanche or some other P2P software that Polygon uses) that also listen for Gossip signals and are willing to add that transaction to their network (e.g., Polygon/Avalanche/whatever). This basically means that those nodes have a different "Blockchain" for each network locally and they work with multiple networks simultaneously, right?

Did I get that right? That means that my account history on each network is naturally different. My question is really just about the technical aspects of this.

Feel free to edit the post to make it use the proper terms and many thanks in advance for reading through this

Answer 1

You've got the general idea, but I'll clarify a few points to help you understand the process better. Ethereum, Polygon, and Avalanche are separate networks with their own consensus algorithms, nodes, and blockchain states. The process of transferring assets from one network to another is facilitated by what's known as a "bridge."

When you're asked to choose a network for your transaction, you're essentially selecting the blockchain on which you'd like to perform the transaction. If you're sending ETH from a Coinbase account to a private wallet, you're likely transacting on the Ethereum Mainnet.

To send assets to another network like Polygon or Avalanche, you'll need to use a bridge. A bridge is a smart contract or a set of smart contracts that lock up assets on one network and mint equivalent tokens on the other network. These bridged tokens are pegged to the original asset, and the bridge ensures that the total supply across both networks remains constant.

With a CEX - this all done behind the scenes, so you select the network and it does the rest. If you use a wallet like MetaMask, you can use the built in Bridge function to swap from one network to another.

So, when you send assets from Ethereum to Polygon, for example, you're not directly interacting with the Polygon nodes from the Ethereum network. Instead, you're interacting with a bridge contract on Ethereum that locks up your assets and mints equivalent tokens on the Polygon network. Similarly, when you want to move the assets back to Ethereum, the bridge contract on Polygon will burn the pegged tokens and release the locked assets on the Ethereum network.

Different networks have separate nodes and blockchain states, and they don't inherently listen for gossip signals from other networks. The interoperability between networks is achieved through bridges and other cross-chain solutions. Each network maintains its own blockchain and state, and your account history on each network will naturally differ.