If a company has multiple data centers located
in different parts of a city, it may want to be able
to move its VMs anywhere in these data centers
quickly and easily. That is, it may want all its
VMs to be connected to a single virtual Ethernet
spanning all these data centers. Again, a medium
access control (MAC) over IP approach like
the ones proposed earlier may be used. Transparent
Interconnection of Lots of Links (TRILL)
[8], which was developed to allow a virtual LAN
to span a large campus network, can also be
used for this.
NETWORK FUNCTION VIRTUALIZATION
Standard multi-core processors are now so fast
that it is possible to design networking devices
using software modules that run on standard
processors. By combining many different functional
modules, any networking device — L2
switch, L3 router, application delivery controller,
and so on — can be composed cost effectively
and with acceptable performance. The Network
Function Virtualization (NFV) group of the
European Telecommunications Standards Institute
(ETSI) is working on developing standards
to enable this [9].