  A wide range of services and applications can be improved and/or solved by
using distributed ledger technology (DLT). These services and applications have
widely varying quality of service (QoS) requirements. However, most existing
DLT systems do not distinguish different QoS requirements, resulting in
significant performance issues such as poor scalability and high cost. In this
work, we present vDLT -- a service-oriented blockchain system with
virtualization and decoupled management/control and execution. In vDLT,
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. In addition, management/control 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.
