  With the innovation of distributed ledger technology (DLT), often known as
blockchain technology, there has been significant growth of digital tokens in
the form of cryptocurrencies, stablecoins, and central bank digital currencies.
As the number of DLT networks increases, each with varying design
characteristics, the likelihood that transacting parties are on the same
network decreases. Thus, it is crucial to facilitate payments that are
universal across networks, scalable to massive loads, and highly available. We
envision a future payment network that may be built on top of DLT networks
without being subject to their limitations on interoperability, scalability,
and availability faced by DLT payment solutions today. Specifically, we propose
a hub-and-spoke payment route, referred to here as Universal Payment Channels
(UPC), that can be used to support digital token transfers of funds across
different networks through payment channels. We further discuss the potential
use cases of the UPC technology to support, and not complicate, an already
robust digital payment ecosystem. Finally, through the paper, we share some
future directions of the UPC technology.
