> For the complete documentation index, see [llms.txt](https://monobridge.gitbook.io/monobridge/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://monobridge.gitbook.io/monobridge/anycall/2.1-requirements-on-the-design-of-generic-cross-chain-messaging-protocols.md).

# 2.1 Requirements on the design of generic cross-chain messaging protocols

The reality of multi-chain co-existence generates the demand for cross-chain protocols, which are supposed to realize generic messaging between chains of different technological systems, just like how common network protocols enable the free communication of messages between different hosts. To this end, the new generation cross-chain protocols are expected to meet the following requirements.

1） Expansion of contents for interaction The new generation cross-chain protocols will no longer focus on the cross-chain swap of digital assets. In order to realize generic cross-chain messaging, the new-generation cross-chain protocols must be able to process and validate more types of messages other than transaction status on the source chain, e.g. data and business logic. 

2） Enhanced adaptability and versatility To meet the requirements of different types of Dapps on generic cross-chain messaging, the new generation cross-chain protocols must also be exceptionally versatile and adaptable. That's why it is inevitable that loose coupling between the cross-chain protocols and the business logic of Dapps be implemented, by setting a trigger for the cross-chain protocol on the source chain and a cross-chain logic execution interface on the target chain. When cross-chain operation is needed, the cross-chain protocol will be triggered on the source chain to transmit business messages and business logic. Then the corresponding business contract will be triggered through the execution interface on the target chain according to the requirements of the Dapp. This is how the Dapp realizes the cross-chain call of contracts. Based on a standard interface for cross-chain calls, the new generation cross-chain protocol builds a generic messaging channel across chains. The standardized interface enables the new generation cross-chain infrastructure to provide generic cross-chain messaging capabilities, whatever type the Dapp is, and whatever the content to be transmitted. As such, cross-chain Dapp developers will no longer need to focus on how to realize cross-chain transfer from a technical perspective, but on how to design specific logic and develop new businesses. 

3\) Decentralization, open source and public accessibility Generic cross-chain messaging protocols that promote the development of cross-chain Dapps in a multi-chain environment must also be decentralized, so as to ensure that the cross-chain Dapps built on such protocols are also decentralized. The protocols must be open source as well, because only open source codes can validate the decentralized design of the protocols and ensure their implementation is secure and reliable. Moreover, generic cross-chain messaging protocols must also be open to the public because they are designed to break the barriers of understanding so that more ecosystems can be connected. Only publicly available open source code meets this standard. In summary, a generic cross-chain messaging protocol must be open source, and its interfaces and services must be publicly accessible, so that any Dapps or developers will be able to use it either directly, or for further development, encapsulation and/or integration.