This seemingly contrived example of transaction history actually provides us with a deep insight into the design of business networks—that one record of all interactions in a network of complex interactions is not a good idea. The example starts to illustrate that it might be better design to associate a business network with a particular concern, rather than trying to combine all history into a single network. In our analogy, it would be better to have different history books for French, United States, and Japanese history and cross-reference them with each other!

This idea has concrete and important consequences for how you approach blockchain networks. It's not just good design, but essential design to separate business networks into those of separate concerns, and then link them together. It will lead to simpler, more comprehensible, more scalable, more extensible, and more resilient systems. You will be able to start small and grow, and be confident that no matter how things evolve you can cope with change. You'll see Hyperledger Fabric explicitly supports the idea of multiple business networks using concepts called networks and channels, and we'll discuss these in more detail later.