Unlike hubs, switches prevent promiscuous sniffing. In a switched network environment, CommView (or any other packet analyzer) is limited to capturing broadcast and multicast packets and the traffic sent or received by the PC on which CommView is running. However, most modern switches support "port mirroring", which is a feature that allows you to configure the switch to redirect the traffic that occurs on some or all ports to a designated monitoring port on the switch. By using this feature, you will able to monitor the entire LAN segment. We wrote a white paper,
Promiscuous Monitoring in Ethernet and Wi-Fi Networks, that covers these topics in detail.