This is a summary of some prior discussions related to network overlays.
Message stratification is an idea to help reduce overall network traffic in various scenarios. In essence, each node is assigned a persistent node ID (a large random number that survives node restarts) and then a network overlay, such as Kademlia , is used to efficiently route messages to relevant nodes.
For instance, once durable votes are implemented, a network overlay enables propagation of votes with far less network traffic. Durable votes would be stored on partitions of the ID key space (the possible permutations given the size of the node id, typically 160 bits). A light node would then query votes in this key space, allowing it to be connected to just a few nodes - the Kademlia distance metric ensures that any key/node can be reached within log(n) steps where n is the number of nodes. A network overlay reduces load on representative nodes since other (partial) nodes store durable votes.