  The maturing of blockchain technology leads to heterogeneity, where multiple
solutions specialize in a particular use case. While the development of
different blockchain networks shows great potential for blockchains, the
isolated networks have led to data and asset silos, limiting the applications
of this technology. Blockchain interoperability solutions are essential to
enable distributed ledgers to reach their full potential. Such solutions allow
blockchains to support asset and data transfer, resulting in the development of
innovative applications.
  This paper proposes a novel blockchain interoperability solution for
permissioned blockchains based on the publish/subscribe architecture. We
implemented a prototype of this platform to show the feasibility of our design.
We evaluate our solution by implementing examples of the different publisher
and subscriber networks, such as Hyperledger Besu, which is an Ethereum client,
and two different versions of Hyperledger Fabric. We present a performance
analysis of the whole network that indicates its limits and bottlenecks.
Finally, we discuss the extensibility and scalability of the platform in
different scenarios. Our evaluation shows that our system can handle a
throughput in the order of the hundreds of transactions per second.
