The answer is Trunking
Virtualization
How do hosts on a physical ring topology communication
You can communicate only with hosts on your own physical network and with hosts on networks for which an explicit route exists, but not with hosts which are beyond the gateway and where no explicit route exists. Or, you can reach local machines but you can't reach Internet machines.
DHSP
They can; that is the usual function of a switch.
Is called virtual hosts.
A virtual serving host offers virtual server facilities to users. Virtual servers are virtual machines that are functionally equivalent to a physical machine, even though multiple virtual servers can be hosted on a single physical server. Some examples of virtual server hosts include DreamHost, Soft Layer and GoDaddy.
to avoid a central part of point of volubility
switch,hub.
A Hub or a Switch
It is called virtual hosts, and it is supported by Apache.
VLAN is Virtual Local area network and it is a group of hosts with a common set of requirements that communicate as if they were attached to the same broadcast domain, regardless of their physical location. VLANs are configured through software rather than hardware, which makes them extremely flexible.