Virtualization 11
priority to a software network whilst preserving the isolation, by
allowing that particular network to spend its tokens as a matter of
priority over the other networks. This is relative priority, because each
network can, at any moment, recoup its basic resources. However, the
priority can be accentuated by distributing any excess resources to the
priority networks, which will then always have a token available to
handle a packet. Of course, isolation requires other characteristics of
the hypervisors and the virtualization techniques, which we shall not
discuss in this book.
Virtualization needs to be linked to other features in order to fully
make sense. SDN (Software-Defined Networking) is one of the
paradigms strongly linked to virtualization, because it involves the
uncoupling of the physical part from the control part. The control part
can be virtualized and deported onto another machine, which enables
us, for example, to have both a far great processing power than on the
original machine, and also a much larger memory available.
1.3. Virtual devices
All devices can be virtualized, with the exception of those which
handle the reception of terrestrial and wireless signals, such as
electromagnetic signals or atmospheric pressure. For example, an
antenna or thermometer could not be replaced by a piece of software.
However, the signal received by that antenna or thermometer can be
processed by a virtual machine. A sensor picking up a signal can
select an appropriate virtual machine to process the signal in order to
achieve a result that is appropriate for the demand. The same antenna
might, for example, receive signals from a Wi-Fi terminal but also
signals from a 4G terminal. On the basis of the type of signal, an
initial virtual machine determines which technology is being used, and
sends the signal to the virtual machine needed for its processing. This
is known as SDR (Software-Defined Radio), which is becoming
increasingly widely used, and enables us to delocalize the processing
operation to a datacenter.
The networking machines which we know can always be
virtualized, either completely or at least partially: the processing part,
www.it-ebooks.info
priority to a software network whilst preserving the isolation, by
allowing that particular network to spend its tokens as a matter of
priority over the other networks. This is relative priority, because each
network can, at any moment, recoup its basic resources. However, the
priority can be accentuated by distributing any excess resources to the
priority networks, which will then always have a token available to
handle a packet. Of course, isolation requires other characteristics of
the hypervisors and the virtualization techniques, which we shall not
discuss in this book.
Virtualization needs to be linked to other features in order to fully
make sense. SDN (Software-Defined Networking) is one of the
paradigms strongly linked to virtualization, because it involves the
uncoupling of the physical part from the control part. The control part
can be virtualized and deported onto another machine, which enables
us, for example, to have both a far great processing power than on the
original machine, and also a much larger memory available.
1.3. Virtual devices
All devices can be virtualized, with the exception of those which
handle the reception of terrestrial and wireless signals, such as
electromagnetic signals or atmospheric pressure. For example, an
antenna or thermometer could not be replaced by a piece of software.
However, the signal received by that antenna or thermometer can be
processed by a virtual machine. A sensor picking up a signal can
select an appropriate virtual machine to process the signal in order to
achieve a result that is appropriate for the demand. The same antenna
might, for example, receive signals from a Wi-Fi terminal but also
signals from a 4G terminal. On the basis of the type of signal, an
initial virtual machine determines which technology is being used, and
sends the signal to the virtual machine needed for its processing. This
is known as SDR (Software-Defined Radio), which is becoming
increasingly widely used, and enables us to delocalize the processing
operation to a datacenter.
The networking machines which we know can always be
virtualized, either completely or at least partially: the processing part,
www.it-ebooks.info