A virtual switch (vsw) is a component running in a service domain and managed by the virtual switch driver. A virtual switch can be connected to some guest domains to enable network communications between those domains. In addition, if the virtual switch is associated also with a physical network interface, then this allows network communications between guest domains and the physical network over the physical network interface. A virtual switch also has a network interface, vswn, which allows the service domain to communicate with the other domains connected to that virtual switch. It can be used like any regular network interface and configured with the ifconfig(1M) command.
When a virtual switch is added to a service domain, its network interface is not plumbed. So, by default, the service domain is unable to communicate with the guest domains connected to its virtual switch. To enable network communications between guest domains and the service domain, the network interface of the associated virtual switch must be plumbed and configured in the service domain. See Enabling Networking Between the Control/Service Domain and Other Domains for instructions.