Twelve years have passed since the blockchain concept was announced. During this time, the concept has evolved rapidly.
Each new generation of blockchain projects has made a quantum leap in security, speed and availability. From the first generation of single-chain, represented by Bitcoin, to the fifth generation of multi-blockchains such as Free TON, the chain-building scheme has branched out.
Now the classification of blockchains has dozens of parameters. In this case, the basic branching of the classification begins with the possible number of chains in the blockchain. Based on this, there are single blockchains (Bitcoin or Etherium) and multiblockchains (FreeTON, PolkaDot, EOS).
Multiblockchains structure the interactions of the chains within the network in different ways. The interconnection of blockchains can be built according to several criteria.
One of the personality parameters of a multi-chain is the homogeneity-heterogeneity of chain types. According to this parameter, multi-blockchain projects are divided into:
If the blockchains of a multi-chain system are of the same type and are built according to the same rules, such a system is called homogeneous.
In a homogeneous system, all chains make transactions in the same format and use a single cryptocurrency. Smart Contracts are also executed by a single virtual machine. The similarity enables blockchains to interact. It is essential that the advantage of similarity be used.
! THE SYSTEM IN A PURE FORM IS NOT IMPLEMENTED IN PRACTICE YET.
If blockchains have different rules and operating mechanisms, and each has its own cryptocurrency, then the system is heterogeneous.
In such a system, there is no interaction between blockchains. The chains are autonomous and practically do not intersect. The Polkadot multi-blockchain is based on this type.
The option when in a multi-blockchain system there are groups of blockchains of a homogeneous and heterogeneous type at the same time is called a mixed system.
There are blockchains with unique rules that are not configured for interaction, as well as groups of blockchains with uniform rules and with active interaction within the group. Free TON uses a mixed type. A mixed system allows you to build a scalable network using sharding.
Heterogeneous systems with multiple workchains with uniform rules
Another variant of blockchains within a multi-chain assumes that all or some of the chains of a heterogeneous system can have uniform rules, but not use them for direct interaction.
In other words, the system is potentially homogeneous, but in fact it is heterogeneous. Even with a single cryptocurrency, blockchains use altcoins – independent variants of the same token.
For a system to be homogeneous, it is not enough to have mechanisms to convert altcoins almost one to one. EOS network can be conditionally attributed to this type. It is inherently heterogeneous, but in order to achieve scalability, it can create several workchains with uniform rules.
As can be seen from the blockchain comparison, multi-blockchain projects can migrate from one type to another depending on the actual processes.