22 Software Networks
orchestrate the network. Later on, we shall describe the current
standards governing this interface. The southbound interface describes
the signaling necessary between the control plane and the
virtualization layer. With this aim in mind, the controller must be able
to determine the elements that will make up the software network for
which it is responsible. In the other direction, the current network
resource consumption must be fed back so that the controller has as
full a view as possible of the usage of the resources. The bandwidth
necessary for the feeding back of these statistics may represent a few
percent of the network’s capacity, but this is crucial for optimization
which will improve performance by much more than a few percent.
In addition to the two interfaces described above, there are also the
eastbound and westbound interfaces. The eastbound interface enables
two controllers of the same type to communicate with one another and
make decisions together. The westbound interface must also facilitate
communication between two controllers, but ones which belong to
different sub-networks. The two controllers may be compatible but
they may also be incompatible and in this case, a signaling gateway is
needed.
Figure 2.7 shows a number of important open-source programs that
have been developed to handle a layer or an interface. Starting from
the bottom, in the virtualization layer, network virtual machines are in
the process of standardization by the ETSI in a working group called
NFV (Network Functions Virtualization), which we shall revisit in
detail later on. Here, let us simply note that the aim of NFV is to
standardize network functions with a view to virtualizing them and
facilitating their execution in different places from the original
physical machine.
The control plane includes the controllers. One of the best known
is OpenDaylight – an open-source controller developed
collaboratively by numerous companies. This controller, as we shall
see later on, contains a large number of modules, often developed in
the interest of the particular company that carried out that work.
Today, OpenDaylight is one of the major pieces in the CISCO
architecture, but also that of other manufacturers. Later on we shall
www.it-ebooks.info
orchestrate the network. Later on, we shall describe the current
standards governing this interface. The southbound interface describes
the signaling necessary between the control plane and the
virtualization layer. With this aim in mind, the controller must be able
to determine the elements that will make up the software network for
which it is responsible. In the other direction, the current network
resource consumption must be fed back so that the controller has as
full a view as possible of the usage of the resources. The bandwidth
necessary for the feeding back of these statistics may represent a few
percent of the network’s capacity, but this is crucial for optimization
which will improve performance by much more than a few percent.
In addition to the two interfaces described above, there are also the
eastbound and westbound interfaces. The eastbound interface enables
two controllers of the same type to communicate with one another and
make decisions together. The westbound interface must also facilitate
communication between two controllers, but ones which belong to
different sub-networks. The two controllers may be compatible but
they may also be incompatible and in this case, a signaling gateway is
needed.
Figure 2.7 shows a number of important open-source programs that
have been developed to handle a layer or an interface. Starting from
the bottom, in the virtualization layer, network virtual machines are in
the process of standardization by the ETSI in a working group called
NFV (Network Functions Virtualization), which we shall revisit in
detail later on. Here, let us simply note that the aim of NFV is to
standardize network functions with a view to virtualizing them and
facilitating their execution in different places from the original
physical machine.
The control plane includes the controllers. One of the best known
is OpenDaylight – an open-source controller developed
collaboratively by numerous companies. This controller, as we shall
see later on, contains a large number of modules, often developed in
the interest of the particular company that carried out that work.
Today, OpenDaylight is one of the major pieces in the CISCO
architecture, but also that of other manufacturers. Later on we shall
www.it-ebooks.info