Application Framework for Programmable Network Control - Advances in Network-Embedded Management and Applications - page 42

Applications exchange information (
network, possibly over the same network the application is controlling (in
band). Even though application
management network, the communication path between network and
application complicates the design and validation of the controller. Network
properties, such as latency and packet loss, limit the amount of informatio
that can be exchanged or synchronized. So, NE state information can become
incomplete, inaccurate or aged.
the limits in information exchange
designing the control application
This section introduced the abstractions needed to provide the basic
framework for network control in the application domain. Next, the details
related to interworking of applications and networks that lead to a functional
model are described.

Applications exchange information (NC x,y ) with NEs over a communication
network, possibly over the same network the application is controlling (in
application developers may have access to a separate
management network, the communication path between network and
application complicates the design and validation of the controller. Network
properties, such as latency and packet loss, limit the amount of informatio
that can be exchanged or synchronized. So, NE state information can become
incomplete, inaccurate or aged. The application developer has to understand
the limits in information exchange of a given network, i.e. observability, when
pplication.
This section introduced the abstractions needed to provide the basic
framework for network control in the application domain. Next, the details
related to interworking of applications and networks that lead to a functional

4 Functional Components

Functional Components

The OSI reference model
networks in seven layers
decomposition of a complex problem, but
lost in the process. If
application interface to the software
problem domain. However,
specific organization of network functions.
of functional components
and organization of network
the context of the NEs
of NEs in the application domain
software representation of NEs to
in the network for filtering
We identify three layers of abstr

The OSI reference model organizes the interworking of applications and
seven layers [36]. The design principle of layering allows
decomposition of a complex problem, but application specific details may be
If network elements are virtualized in software, the
to the software (NCs) can be fine-tuned to the specific
. However, the fine-tuning might lead to an application
organization of network functions. Here, we define the organization
of functional components to support fine-tuning of the application interface
network functions. The functional organization preserves
by creating and managing the software representation
of NEs in the application domain. For example, an application can use the
software representation of NEs to manipulate traffic of a single strategic point
in the network for filtering or anomaly detection purposes.
identify three layers of abstraction in a distributed program: network

Four functional layers characterize practical application domain network

Fig. 3. Four functional layers characterize practical application domain network
control.