In this chapter, we covered the basics of the XMPP protocol and some of its strengths and weaknesses. We saw how we can use it in our sensor, actuator, and controller projects as a simple means to create IoT applications. We also used the flexibility of the XMPP protocol to add an additional layer of security to each project using the pattern of delegated trust.

This chapter concludes with an overview of the different protocols used in IoT. For a comprehensive comparison between the protocols, listing features and perceived strengths and weaknesses of each in a table format, please refer to the paper Biotic - Executive Summary at http://biotic-community.tumblr.com/.

In the next chapter, we will introduce you to the use of platforms for IoT, and what additional features they provide when developing applications for IoT.