As organizations implement virtualized environments, knowing how to monitor and maintain them becomes yet another challenge. This white paper presents various visibility options for monitoring a virtualized environment.
"Before discussing monitoring options within a virtual environment, lets take a moment to discuss how the traffic flows within it. Virtual environments are designed to include a virtual adapter (vNIC) for each virtual machine within the system. The vNIC is logically connected to a virtual switch, which is managed by the virtual host system (see the diagram below). This addresses communication which would remain in the VM host. In order to enable communication into and out of the VM host, a logical connection between the vNIC and the pNIC must be established."