Fog computing is also called Edge computing. In this model, data, computing and storage are gathered in devices at the edge of the network rather than at its core. CISCO introduced the phrase Fog Networking to define this new model which allows objects to connect to edge devices.
6.1. Fog architectures
Before splitting Cloud architecture into four main levels (Cloud, MEC, Fog and Skin), it was first strongly centralized around a central datacenter, then split into two between the Cloud and the Fog, as shown in Figure 6.1.
Fog covers everything located at the endpoints of the network from the edge router, from the operator’s side or from the company’s side. If located on the company’s side, the Fog server is then called NAC (Network Access Controller). If it is located on the operator’s side, the Fog server is an SBC (Session Border Controller), which today has greater functions than it originally had, to secure VoIP and play the part of a SIP firewall.
The word Fog can sometimes be used for very small datacenters, which we will mention in Chapter 7 under the name “skin datacenters”. Indeed, the users are close to the Wi-Fi or the femtocell access points that are embedded into the skin datacenter. This case is described in Figure 6.2.
Many examples of Fog datacenters ...