Polkadot Launches Testnet for Sharding Cross-Communication

The Polkadot (DOT) project launched a testnet to evaluate its planned sharding implementation based on parachains.

The key component that separates shards from being just many independent blockchains is communication. Shards need to be able to communicate with their peers to enable cross-shard token transfers and other forms of interoperability.

Called Rococo, the new testnet is designed specifically to test Polkadot’s inter-shard communication protocols. It was released on Aug. 4 and teased by Parity developer Bastian Köcher.

At launch, three separate parachains called tick, trick, and track will be available. Developers will also be able to add their own parachains. The network is based on a consensus algorithm known as Proof-of-Authority, which is essentially a form of trusted consensus which incorporates an admin key. This mechanism was chosen because consensus is not so important for the testnet’s current purposes.

At launch, Rococo supports Horizontal Message Passing — a way of sending messages and thus tokens between parachains by going through the Relay Chain. This has a similar purpose to Ethereum’s Beacon Chain.

Polkadot’s eventual goal is to implement Cross-Chain Message Passing, which would avoid using the relay chain to pass messages and thus enable quicker and more direct communication.

The Rococo testnet is an important milestone in Polkadot’s complete sharding rollout, as currently the blockchains are largely isolated entities. Developers warned that the system is not yet entirely stable and will be updated with new code later on to gradually prepare for a mainnet release.

This follows Polkadot’s mainnet release in July, although with somewhat limited functionality.

Projects building on Substrate

Polkadot’s architecture is based on the concept of parachains, which are independent but cross-communicating blockchains. Parachains are themselves based on Substrate, which is a blockchain building framework that provides the software foundation for parachains. Substrate-based blockchains can be used in stand-alone mode as well, but a framework called Cumulus makes it very easy to integrate them into Polkadot.

So far, many projects are building on Substrate in preparation for the network’s eventual launch.

Cointelegraph recently reported on a DeFi project called Stafi that creates liquid IOUs based on staked tokens.

Other projects include a Bitcoin-to-Polkadot bridge, Chainlink, Celer Network and many others.

The project is also pushing heavily to bring new developers to the ecosystem thanks to a collaboration with Gitcoin.