  We describe a new public-domain open-source simulator of an electronic
financial exchange, and of the traders that interact with the exchange, which
is a truly distributed and cloud-native system that been designed to run on
widely available commercial cloud-computing services, and in which various
components can be placed in specified geographic regions around the world,
thereby enabling the study of planetary-scale latencies in contemporary
automated trading systems. Our simulator allows an exchange server to be
launched in the cloud, specifying a particular geographic zone for the cloud
hosting service; automated-trading clients which attach to the exchange can
then also be launched in the cloud, in the same geographic zone and/or in
different zones anywhere else on the planet, and those clients are then subject
to the real-world latencies introduced by planetary-scale cloud communication
interconnections. In this paper we describe the design and implementation of
our simulator, called DBSE, which is based on a previous public-domain
simulator, extended in ways that are partly inspired by the architecture of the
real-world Jane Street Exchange. DBSE relies fundamentally on UDP and TCP
network communications protocols and implements a subset of the FIX de facto
standard protocol for financial information exchange. We show results from an
example in which the exchange server is remotely launched on a cloud facility
located in London (UK), with trader clients running in Ohio (USA) and Sydney
(Australia). We close with discussion of how our simulator could be further
used to study planetary-scale latency arbitrage in financial markets.
