The network manager at Evco Insurance is pleased that you have helped figure out some of his hub problems. However, the longer he talks with you, the more convinced he is at the Marketing Department could benefit from being connected to the network backbone through a switch. He likes the idea of giving certain users or groups of users a dedicated channel to the LAN. He thinks he might want to take this approach. 
The network manager understands the performance benefits that users would gain, but he still isn't sure which users should get the benefit of switching.
What can you tell him about security that might help him decide which users' nodes should be switched?