This is the last chapter in which we'll increase your knowledge of ReactiveX. This chapter explains how observables can be extended outside a single application. The first part of this chapter explains what existing communication patterns there are and how they relate to observables. The second part details how multiplexing is designed and why all of its steps are necessary. The last part is an implementation of the publish/subscribe protocol.

The following topics will be covered in this chapter:

• Communication patterns and observables
• Observable multiplexing
• Implementing publish/subscribe