What is a parachain slot?

First, we need to review Polkadot's architecture. Polkadot is essentially a scalable heterogeneous multi-chain blockchain consisting of a collaborative decentralized blockchain network, which can also be called a relay chain. The relay chain interacts with the parallel running shard chains (that is, parachains). These parachains can be regarded as clients of the relay chain. The purpose of the relay chain is to protect the smooth operation of the parachain.

Polkadot allows multiple dedicated blockchains to communicate with each other in a secure and trustless environment, thereby realizing the scalability of the blockchain. The parachain is connected to the relay chain, which requires a parachain slot. Only by obtaining a slot can it become a "polkadot parachain" in the true sense, because the slot can provide the security of Polkadot sharing, cross-chain interoperability, on-chain governance, no-fork on-chain upgrades, scalability, Advantages such as low handling fees.

Simply understand, it is like the parachain is all kinds of electrical appliances in life, and the socket of the Polkadot relay chain is like a power socket. Only when the electrical appliance is connected to the socket, can it play a real role.

What is a Parachain Slot Auction?

However, the parachain that a relay chain can carry is limited, and the parachain slot naturally becomes a scarce resource. So many projects want to connect to Polkadot. Naturally, there are too many things to do, so what should be done to make it happen? How about the fair and equitable distribution of slots? The most suitable solution for this situation is to auction.

So Polkadot officially designed the parachain slot auction mechanism. In order to ensure a fair distribution of parachain slots, Polkadot uses candle auctions to bid for parachain slots.

Candle auction is a form of public auction, where bidders submit higher and higher bids, and the bidder with the highest bid at the end of a randomly determined auction time is considered the winner. In the Polkadot Parachain Slot auction, anyone can participate. The auction is conducted on the blockchain with a random end time that can be traced back. If anyone (individual or smart contract) wins the auction, no permission is required. They can deploy their parachains. Polkadot Parachain slot auctions are essentially decentralized.

Due to the feature that anyone can participate, as of the official start of the parachain auction, we are unable to determine the specific number and status of the projects (or individuals) participating in the auction. Once the bidding starts, all participating data will be publicly available on the chain, and the official will announce the specific start time and end time of the bidding.

In addition to the end time that everyone knows, the Polkadot system will generate a random end time, which will be converted into the number of blocks, and this is the key to determining the final winner. Teams that have not won the slots can participate in the next round of slot auctions, generally every two weeks.

All participants need to determine two pieces of information: the number of tokens participating in the auction and the slot time for the auction. The slot time for bidding is determined according to the needs of the ecological project, not necessarily as long as possible. Another thing that needs to be discussed is the number of tokens participating in the auction. After all, the more the better, and the "passing line" must not be missed.

Number and type of parachain slots

Although the design space of the blockchain system is infinite, the parachain that the relay chain can carry is limited. Based on the current design, Polkadot will generate about 100 parachain slots.

And these 100 parachains will not all be used for slot auctions. In fact, some of the basic functions required by Polkadot's entire ecology are reserved for special slots to meet the necessary needs. This fits the plan very well. The idea of economy + market economy.

At present, parachain slots are specifically divided into public interest chain slots, parachain slots, and parallel thread pools.

According to the introduction to the "Public Interest Parachain" published on Polkadot's official blog, it is indicated that a referendum will be used to determine the registration slot for the Public Interest Parachain. The public interest chain is divided into two categories, which are used for the election, governance and identity of staking and council, the "system parachain" used for balances, and the "system parachain" represented by bridges, general asset chains and DOT-priced smart contract platforms. "Public function parachains", about 10-30 public interest parachains are reserved.

In addition, a part of the slots are called leased slots, that is, this part of the slots will be used in the parachain slot auction. The Polkadot Parachain Slot auction obtains lease rights, and its useful life is limited, with a unit of 6 months and a maximum of 2 years. It is provided for general parallels that require continuous network throughput resources and all functions of the Polkadot ecosystem. Chain project.

The last remaining part is the parallel thread pool. The parallel thread pool is a collection of dynamic usage rights of blocks by bidding in open parachain slots, and each block carries up to 50 parallel threads.

What is the online process of Parachain?

• Launch Rococo v1 and wait for its stable operation;
• Online Kusama's system (public interest nature) parachain;
• Open the auction on Kusama;
• Online Kusama has successfully bid on the parachain;
• After the audit is completed, the public interest parachain of Polkadot will be launched;
• Open the auction on Polkadot;
• Online Parachain of successful bidding on Polkadot.