Polkadot: Under the Hood

Before going somewhere, it is always better to know a bit about the lay of the land. Similarly before starting development, its recommended to navigate and to explore the platform to be used for development. In this article, I talk about the tech underlying the Polkadot network to understand ‘what makes it tick’!

Let’s start of with the definition of the network elements that can be found in the Polkadot ecosystem.

Relay Chain is the heart of Polkadot network. It beholds the responsibility to manage the network’s shared security, consensus and cross-chain interoperability.

Parachains are independent blockchains, with their own tokens and are free to optimize their functionality for specific use cases. Looking forward to the auction of parachain slots.

Parathreads are similar to parachains but work with a pay-as-you-go model. It is a more economical way for blockchains that don’t need continuous connectivity to the network.

Bridges allow parachains and parathreads to connect and communicate with internal chains as well as external blockchain networks making the network scalable across chains.

The projected Polkadot network https://polkadot.network/

So to put things in context, Polkadot unites a network of heterogeneous blockchains called parachains and parathreads which connect to and are secured by the Polkadot Relay Chain. They have the option to connect with external blockchain networks via bridges — few such bridges are already in place while more are being built.

Much like in a democracy, everyone has to play a part to make a decentralized and distributed system work efficiently. The Polkadot network comprises nominators, validators, collators and fishermen. A brief about each of them is outlined below.

Nominators secure the Relay Chain by selecting credible validators and staking DOT. Validators secure the Relay Chain by staking DOT, validating proofs from collators and participating in consensus with other validators. Thereby playing a crucial role in adding new blocks to the Relay Chain, allowing parties to complete cross-chain transactions via the Relay Chain. Collators sit atop parachains and provide proofs to validators based on transactions from the parachain, thereby helping maintain parachains by aggregating parachain transactions and producing state transition proofs for validators. Fishermen are same as collators but instead of packaging the state transitions and producing the next parachain blocks as collators do, fishermen observe the validation process and ensure no invalid state transitions are included.

Polkadot uses GRANDPA and BABE for its hybrid consensus which splits up the finality gadget from the block production mechanism. Polkadot uses its original GRANDPA (GHOST-based Recursive Ancestor Deriving Prefix Agreement) consensus for a more secure and resilient network. BABE (Blind Assignment for Blockchain Extension) is the block production mechanism that runs between the validator nodes and determines the authors of new blocks. Additional details to follow in the next article about Polkadot Consensus.

Concluding Insights

A robust security model, open governance, faster application development, interoperability and ease of usage are a few advantages of building in the Polkadot ecosystem that can be easily observed at first glance. Now that we are aware of the who’s who of the network we can take a closer look on the consensus protocol and try our hands at development as well.

Details for the same will be provided in the next few articles.

Blockchain learner, enthusiast and mentor