The main testnet for BCH, testnet3, has gotten bloated. People have used it for testing 32 MB block propagation for weeks on end. As a result, testnet3 now takes a long time to sync and is kinda annoying to work with. I think the problem here is that we’ve had two separate use cases for a testnet which don’t mesh well. I think we would be better served if we replaced testnet3 with two separate nets.
I propose we add two new testnets to BCH full nodes: testnet4 and scalenet.
testnet4 is optimized for convenience. It’s intended to be kept lightweight and quick to sync. Its main purpose is for compatibility testing and feature testing. Writing a new transaction script, and want to test it out? Developing a full node or a wallet, and want to make sure it speaks the p2p language correctly? Don’t want to bother with paying for a 1 Gbps pipe and 512 GB SSD just to make sure you can send a 200 byte transaction? If so, testnet4 is the place for you to be. testnet4 will come with a default 1.2 MB blocksize limit to discourage spamming, and a 1 hour ASERT half-life to make sure that it can recover to CPU mining quickly after anyone uses an ASIC.
scalenet will be the proving ground for high-throughput activity. Want to check how long it takes for your node to process a 128 MB block? Want to measure block propagation time? Want to spam stuff just for fun? Great! Scalenet is the place for you to be. Scalenet will be reset every 6 months or so (probably by changing a checkpoint block at e.g. height 10,000), so don’t worry about doing long-term damage to the syncability of scalenet. (Yes, this means that scalenet will not accurately simulate blockchain storage costs, but that’s easy enough to calculate manually, and is relatively uninteresting.) scalenet will have a default block size limit that is a few times higher than mainnet’s limit, and can serve as a proving grounds to determine when limit increases are safe for mainnet. ASIC mining on scalenet will be encouraged, and the ASERT half-life will be 2 days in order to allow accurate explorations of mining shenanigans (should anyone want do them).
Testnet4 is online already (though its parameters have not yet been finalized, and no seeders exist yet):
Scalenet is coming soon.