  In this paper, we conduct an experimental study to provide a general sense of
the application response time implications that inter-cluster communication
experiences at the edge at the example of a specific IoT-edge-cloud contiuum
solution from the EU Project ICOS called ClusterLink. We create an environment
to emulate different networking topologies that include multiple cloud or edge
sites scenarios, and conduct a set of tests to compare the application response
times via ClusterLink to direct communications in relation to node distances
and request/response payload size. Our results show that, in an edge context,
ClusterLink does not introduce a significant processing overhead to the
communication for small payloads as compared to cloud. For higher payloads and
on comparably more aged consumer hardware, ClusterLink version 0.2 introduces
communication overhead relative to the delay experienced on the link.
