Network infrastructure is also the part of the discussion when we discuss about network components. So, of course, the question is, what is network infrastructure? In its simple format the answer would be that network infrastructure is any physical and logical network component that enables connection, communication, operation, management, and security of the network.

No matter what professional background you might have, it is just enough to get to know the name of the firewall and you will immediately think that there is no joke with such device. Leaving the humor aside, a firewall (see Figure 1.16) is a network device that provides security to the network infrastructure. It does so by controlling and monitoring both incoming and outgoing traffic based on configured security rules. In a nutshell, the firewall to a network infrastructure is like a security officer at an organization's main gate:

Nowadays, we often hear expressions like "I got connected to the internet with wireless" or "I've found an open wireless." This and many other similar expressions make us understand that the discussion is about the access point. That said, an AP (see Figure 1.17), often known as a wireless access point, is a network device that enables access to the wired network. With APs in a network infrastructure, the network becomes more accessible by enabling the access to organization services while on the go. In addition, it enables the support for the new trends like Bring Your Own Devices (BYOD):

Since network infrastructure has many network devices, including APs for the security purposes as well as for the quality of services (QoS), organizations will employ a wireless access controller. It is a networking device that enables organizations to centrally manage APs.