A brief analysis of the similarities and differences between Polkadot Parachain and Ethereum 2.0 architecture design


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In terms of overall architecture, Ethereum 2.0 is surprisingly similar to Polkadot, but there are many differences in details and concepts.

Title of original text: “Polka Parachain and ETH 2.0”
Written by: Tan Guopeng, founder of Ownbit

Last night, the Polkadot ecological chain project Moonbeam and Ownbit had a technical exchange, hoping that Ownbit would better support the Polkadot ecological chain in the future (including support for Moonbeam). Moonbeam will also compete to become the first batch of Polkadot parachains. Taking advantage of the opportunity of communication, I also have a deeper understanding of the Polkadot Parachain, so this article was written.

ETH 2.0 and Polkadot Parachain are two important technologies in the future. Although they belong to two different heavyweight projects, they are surprisingly similar in design.

Polkadot Parachain

In the design of Polkadot, there are two important concepts, one is the Polkadot Parachain, and the other is the Polkadot Parathreads . Understanding these two concepts is an important part of understanding the entire Polkadot ecology.

The Polkadot Parachain , hence the name Siyi, is another chain parallel to the Polkadot main chain. To become a parallel chain, we need to occupy a slot Boca system (slot). The number of slots in the Polkadot system is limited (version 1 may support 100 slots). Polkadot designed a slot auction system to obtain a limited use right of a slot through a bid (DOT) auction (each time for 2 years).

Therefore, every time the slot is occupied for a limited period of time, the slot auction shall be repeated after the expiration. The DOT used for bidding will be returned after the expiration of the slot usage, so the use of the slot only takes up the amount and does not cost the funds.

Why become a Polkadot Parachain?

Becoming a Polkadot parachain has two main benefits: the chain itself is more secure , and it has interoperability with other parachains .

In order to better understand the concept of a more secure chain , we can imagine the Polkadot system as a container that can hold multiple parachains. Each parachain will have its own consensus mechanism and the way to generate blocks. The container regularly collects all blocks generated by the parallel chain to form a block at the container level. This container is called in Polkadot: Relay Chain . To be packaged by the relay chain is called the finalize of the block for the parachain .

The final confirmation of the parallel connected blocks by the Polkadot relay chain makes the parachain more secure . In this way, each parachain can benefit from the strong consensus of the Polkadot system, without worrying about various consensus-level attacks or problems in this chain.

The interoperability of Polkadot Parachain and other parachains is another advantage. Polkadot has designed a set of message passing system (Cross-chain Message Passing) at the system level, which allows parachains to pass messages to each other, execute instructions, transfer tokens, and so on. Parachains define the types of messages they can receive and process according to XCMP, so that they can have interoperability with other parachains.

If the parachain is likened to the process in the operating system, then XCMP can be understood as the inter-process communication mechanism IPC (InterProcess Communication).

Parachain resources are limited

Because parachain resources are limited, most chains may not be able to bid for the parachain slot. At this time, the official program Boca is given, using a test network KUSAMA, or parallel threads (Parathreads).

The difference between parallel threads and parachains is only one point: Parachains permanently occupy relay chain resources, while parallel threads only occupy them when needed . When the parallel thread needs the relay chain to finalize its block, it makes a request and pays a certain fee. Because there will be multiple parallel threads requesting confirmation at the same time, the relay chain will make a priority selection according to the level of the cost given. As shown below:

Compared with the parachain, the use of parallel threads eliminates the need to participate in slot auctions, so there is no need for large startup funds. For some applications that do not require frequent confirmation (for example, applications that generate a block in an average of a few minutes or even an hour), using parallel threads is more suitable.

ETH 2.0

The circuit diagram of ETH 2.0 is advancing according to sharding technology. Sharding technology first appeared in database technology. In order to allow the database to have a greater ability to execute queries or inserts, a database (the same table in) is split into multiple databases and deployed on multiple machines, so that the execution ability is doubled.

ETH 2.0 splits the Ethereum network into multiple slices (supporting 1024 slices), increasing the execution capability of Ethereum by a corresponding multiple. Each shard is a sub-network (equivalent to a Polkadot parachain ). The module that handles the ETH 2.0 consensus and the communication between the various sub-shards of the system is called: Beacon Chain , which is equivalent to the Relay Chain in the Polkadot network. The ETH 2.0 fragmentation diagram is as follows:

简析波卡平行链与以太坊 2.0 架构设计异同

It can be seen that ETH 2.0 is surprisingly similar to Polkadot in terms of large architecture. But there are many differences in details and concepts.

Polkadot Parachain VS ETH 2.0

From the design purpose, the Polkadot parachain is mainly for cross-chain purposes, through the horizontal expansion of the parachain to solve the performance throughput problem. The design of ETH 2.0 is entirely to solve the performance throughput problem.

Both Polkadot and ETH 2.0 have the status confirmation function ( finalize ). ETH 2.0 finalize every epoch, and an epoch is defined as 64 blocks, so finalize every 6-12 minutes. The finalize time of Polkadot network is even shorter, generally within 1 minute.

In terms of consensus mechanism, ETH 2.0 and Polkadot also have obvious differences. ETH 2.0 adopts the PoS mechanism. Staking 32 ETH can become a validator. Each shard requires at least 256 validators to finalize. Based on 64 shards, ETH 2.0 needs 16,384 verifiers. Polkadot adopts the nominated PoS (Nominated Proof of Stake) mechanism, and the number of validators required is much less than ETH 2.0. About 10 validators are required for each parachain. Based on 100 parachains in the entire system, 1,000 verifications are required By.

Another difference is that Polkadot is a framework for interconnection between different systems (parachains). And ETH 2.0 is a framework for interconnection between the same system (each shard).

Polkadot pays more attention to other chains, while ETH 2.0 only pays more attention to itself, which also reflects their different prospects for the future. Polkadot creates a scene where multiple chains coexist and interconnect. ETH 2.0 creates a powerful and unified underlying blockchain system, and the upper-level prosperous DApps are interconnected with each other through the application interface (ABI).


Polkadot naturally has cross-chain advantages between parallel chains. And ETH 2.0 does not have cross-chain capabilities. But this does not mean that this wave of cards is much stronger than ETH 2.0 in terms of cross-chain.

For example, for a cross-chain Bitcoin network, Polkadot needs to use a bitcoin-bridge to complete the cross-chain. And this point is consistent with the Ethereum cross-chain Bitcoin solution. Therefore, for cross-chain, Polkadot has advantages only for the parachains deployed on the Polkadot network in the future.


The Parachain project of Polkadot is currently in full swing. Whether they will occupy a very important position in the future will be one of the biggest highlights of the blockchain.

In terms of time, Polkadot’s mainnet went online late, missing the prime time of Ethereum development in the past few years. However, the launch of ETH 2.0 will be two years later, and the Polkadot Parachain project is expected to be launched on the Polkadot mainnet at the end of this year or early next year. This also gives Polkadot more time to catch up with Ethereum. So whether the Polkadot network can shine like Ethereum in the future is very worthy of our attention!

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