Routing

Routing is the mechanism of sending packets of data from a source component to a target component. Routing is categorized into different types. One uses the so-called OSI model (see reference in the Further reading section of this chapter) to distinguish between different types of routing. In the context of containers and container orchestration, routing at layers 2, 3, 4, and 7 is relevant. We will dive into more detail about routing in the subsequent chapters. Here, let's just say that layer 2 routing is the most low-level type of routing, which connects a MAC address to a MAC address, while layer 7 routing, which is also called application-level routing, is the most high-level one. The latter is, for example, used to route requests having a target identifier that is a URL such as example.com/pets to the appropriate target component in our system.