Computer networking is the plumbing of
computing, and like plumbing in all beautiful
buildings, networking is the key to many of the
features offered by new computing architectures.
Virtualization in networking is also not a new
concept. Virtual channels in X.25-based telecommunication
networks and all subsequent networks
allow multiple users to share a large
physical channel. Virtual local area networks
(VLANs) allow multiple departments of a company
to share a physical LAN with isolation.
Similarly, virtual private networks (VPNs) allow companies and employees to use public networks
with the same level of security they enjoy
in their private networks.