One important piece of a multilevel security defense for companies of almost any size is network access control (NAC) The basic idea behind NAC — which can include hardware, software or a combination — is deceptively simple. NAC requires that network administrators piece together hardware and software from multiple vendors, unless you’re willing to go with an all-in-one solution and risk vendor lock-in. While there has been no agreement on even a standard definition of NAC, never mind how to get there, some progress has been made.”]
Source: https://www.csoonline.com/article/2125486/nac-decisions-you-need-to-make-now.html