A fundamental concept on the world wide web is Layering. All the protocols in the net stack talks to the layer directly above and below it new protocols could be used as long as they talk the language of their coating. Protocols at the same layer can be updated so long as they do not break compatibility with the layer above or below it. This structure maximizes interoperability and enables a whole lot of flexibility. The shape of the layers was described as an hourglass, like this:
Beyond layering in the protocol level, we’ve gone on to create layers in the infrastructure and application levels. Infrastructure like AWS and Cloudflare, software libraries such as Node, Rails, and jQuery, services such as Twilio and Stripe. To create an application now, you don’t have to go build a data center (or many of them), think of how to manually process HTTP requests, or write bare-metal adapters into the telecom or payments systems.
In the crypto/blockchain area, we’re just at the very start of establishing layers. A significant reason for this is that the introduction of cryptocurrencies and tokens, which provide a powerful incentive — for now — for beginning new networks and maximizing value of current networks.
Within blockchains, layers delineate networking (libp2p as a major tool), consensus (tendermint, hashcash and others), applications/smart contracts, and possibly indexing/search (something everyone is doing in their own at this time, but that thegraph is seeking to solve as a coating ).
Perhaps the most intriguing question is how different blockchain systems may coating together. Cosmos and Polkadot are building systems for interoperable blockchains using a hub-and-spoke model, with shadow resources pegged to external chains for interoperability. Interledger is trying to become a more universal cross-ledger (ledger, meaning blockchains and differently ) protocol, akin to TCP/IP from the center internet stack.
These systems interconnect, and coating atop one another, seems like a fundamental question as we go from the speculative phase to the operational phase. We’re just now starting to get glimpses of it.