Real-time distribution of status and control information. Here we have small messages that need to be propagated throughout the network in real time, such as for the mapping systems inputs and outputs (load, health, connectivity, and control information. For these, we use a publish/subscribe model with multi-path tiered fan-out architecture. Publishers announce to a set of globally distributed intermediate nodes. Subscribers can subscribe to one or more of these intermediates. This multi-path architecture minimizes latency while enabling scaling and tolerance of network faults.
