NAC’s(Network Access Control) role is to restrict network access to only compliant endpoints and (31) users. However, NAC is not a complete LAN (32) solution; additional proactive and (33) security measures must be implementeD. Nevis is the first and only comprehensive LAN security solution that combines deep security processing of every packet at 10Gbps, ensuring a high level of security plus application availability and performance. Nevis integrates NAC as the first line of LAN security (34) . In addition to NAC, enterprises need to implement role-based network access control as well as critical proactive security measures--real-time, multilevel (35) inspection and microsecond threat containment.

A．port

B．connection

C．threat

D．insuranc

若正数a、b满足ab=a+b+3，则ab的取值范围是______．