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Signalling aspects 3

7 The signalling architecture

Figure 7-1 – Signalling interface

IPv6 transition technologies are presented as software Apps and are loaded into the control layer which is
responsible for IPv6 application/transition support function via plug-in method. An IPv6
application/transition support function interface (Sn), which may use network configuration protocol
(NETCONF)/YANG, describes IPv6 application/transition support function needed, which is independent of
IPv6 application/transition technologies. The App layer generates the operation request based on the IPv6
application/transition support function data model configured, and sends the request to the IPv6
application/transition support function in the control layer. The IPv6 application/transition support function
enables the Apps to manipulate the traffic via the Sn interface.

8 Signalling requirements

8.1 Component functions

8.1.1 App layer
The application modules in the App layer provide the abstracted application program interfaces (APIs) and/or
user functions. It receives the packet about the IPv6 transition technologies APP of new IPv6 flows from the
control layer after the control layer receives the events from the network devices in the data plane. Then it
sends appropriate instructions to the SDN-enabled device via the control layer and the Sn interface.

8.1.2 Control layer
The control layer provides a northbound interface (Sn) that enables the IPv6 transition technologies App to
modify the traffic using OpenFlow. It receives the events from the network devices and sends it to the App
layer if necessary. After receiving the instructions from the App layer, the control layer translates the
commands of the IPv6 transition technologies APP to a command that can be executed by the SDN-enabled
device.

8.2 Interface requirements

The control layer provides a northbound interface (Sn) that enables the IPv6-transition App to modify traffic
at the data plane using OpenFlow. Specifically, the control layer provides an OpenFlow driver that enables
the IPv6-transition App to decide how the SDN-enabled packet-forwarding devices treat traffic using the Sn
interface. This interface is used to provide an IPv6 application/transition support function interface to any
IPv6-transition application. It mainly provides the following functions:

– Registration and removal function for applications;
– IPv6 application/transition support function data model for packets and flow tables interaction
between controller and applications;

– Adapting packet-in events into neutral events in the interface;

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