vDLT: A Service-Oriented Blockchain System with Virtualization and Decoupled Management/Control and Execution
To support a wide range of services and applications using distributed ledger technology (DLT), a paradigm shift is needed from the existing “blockchain-oriented” DLT systems to next generation “service-oriented” DLT systems.
Recently, distributed ledger technology (DLT) (e.g., blockchain) has attracted great attentions from both industry and academia. Similar to TCP/IP (transmission control protocol/Internet protocol), which laid the groundwork for the development of the Internet, DLT has great potential to create new foundations for our socio-economic systems by efficiently establishing trust among people and machines, reducing cost, and increasing utilization of resources. With the rise of DLT, socio-economic transactions are improving as we shift from the Internet of information (IoI) to the Internet of value (IoV).
A wide range of services and applications can be improved and/or solved by using DLT. Although the first killer application of DLT is cryptocurrency (e.g., Bitcoin), the underlying constructs do not have to be limited to payment transactions. The services and applications of DLT include supply chain management, identification, healthcare, music, energy, gaming, agriculture, transportation, publishing, etc. The `World Economic Forum’ anticipates that 10% of global GDP will be stored on the blockchain by 2025. The impact of DLT could be as grand as the traditional Internet revolution itself.
Nevertheless, a number of non-trivial issues in the current DLT systems prevent them from being used as a generic platform for different services and application across the globe. One notable drawback is the scalability issue. Bitcoin can process about 7 transactions per second (TPS), and Ethereum has the ability of processing about 15 TPS, which is far below the mainstream payment systems, e.g., VISA with more than 2,000 TPS capability. With even one popular application (e.g., CyptoKitties in Dec. 2017 and FCoin in July 2018), Ethereum can be severely congested with significantly increased delay and transaction fee.
There is no silver-bullet that solves all these problems due to the Trilemma as described by Vitalik Buterin, the founder of Ethereum: DLT systems can only at most have two of the following three properties: decentralization, scalability and security. Most of the recently developed DLT systems focus on increasing transaction throughput to improve scalability, e.g., Lightning Network, Raiden Network, Sharding and Plasma, Cardano, EOS, Zilliqa, etc.
Similar issues occurred in the development of the traditional Internet. In the 1990s, with more and more applications built on TCP/IP, the Internet became often congested, and the performance of some applications (e.g., video streaming) was not acceptable for massive popularity due to network congestion (Youtube was not launched until 2005.). With the rapid transformation of the Internet into a commercial infrastructure, demands for service quality have rapidly developed. One intuitive solution was to increase the link bandwidth (and hence the throughput) by deploying fibers and wavelength-division multiplexing (WDM). People believed that, with bandwidth so abundant, the quality of service (QoS) will be automatically delivered. This solution is very similar to ideas behind most of the recently proposed DLT systems, i.e., increasing TPS. Indeed, TPS has been regarded as one of the most important parameters in designing a DLT system.
However, the history of the traditional Internet has told us that increasing throughput alone cannot solve the congestion problem. Even worse, increasing throughput without proper QoS designs may aggravate the congestion problem. There are several reasons for this: heterogeneous QoS requirements from different applications, dynamics of applications, dynamics of available resources, distributed networks without central coordination, etc.
In DLT systems, these situations still apply. For example, different services and applications built on DLT have widely varying QoS requirements. While instant confirmation is desirable when you are buying a cup of coffee using cryptocurrencies, confirmation latency can be tolerated when you are buying a house or conducting computation-intensive machine learning tasks. Moreover, in addition to TPS, other metrics should be considered, such as cost (e.g., transaction fee (a.k.a. gas) in Ethereum and RAM costs in EOS). While it may be ok to pay $1 transaction fee to buy a cup of coffee, it is undesirable to pay $1 for transferring several bits (e.g., reading temperature) in Internet of things (IoT) applications with billions of IoT devices, or $1 for creating an account in social media applications with billions of users. Furthermore, while privacy is the main concern in some applications, others may not care about privacy.
To address these issues, we present vDLT — a service-oriented blockchain system with virtualization and decoupled management/control and execution.
The distinct features of vDLT are as follows.
- Unlike most existing DLT systems that do not distinguish different services and applications, vDLT explicitly considers the QoS requirements of different services and applications. Specifically, services and applications are classified into different classes according to their QoS requirements, including confirmation latency, throughput, cost, security, privacy, etc.
- This is a paradigm shift from the existing “blockchain-oriented” DLT systems to next generation “service-oriented” DLT systems.
- Different QoS requirements are fulfilled by advanced schemes inspired by the development of the traditional Internet, including classification, queuing, virtualization, resource allocation and orchestration, and hierarchical architecture.
- Management/control (e.g., governance, smart-contract-execution nodes selection, and resource allocation) and execution of smart contracts are decoupled to support QoS provisioning, improve decentralization, and facilitate evolution in vDLT.
- With virtualization, different virtual DLT systems with widely varying characteristics can be dynamically created and operated to accommodate different services and applications.
For more details, please visit vDLT.io.
