Class Diagram

Based on ONF Core IM (https://3vf60mmveq1g8vzn48q2o71a-wpengine.netdna-ssl.com/wp-content/uploads/2018/01/TR-512_v1.3.1_OnfCoreIm-info.zip).

ONAP Wan Connection IM is designed as below class diagram:

• Wan Connection: The Wan Connection is Resource Composite.
• Forwarding Construct: The Forwarding Construct (FC) class models enabled constrained potential for forwarding between interfaces at a particular specific layerProtocol. 
• FC Port: Fowarding Construct Port. The association of the FC to interfaces is made via FC Ports. The FC Port class models the access to the FC function.  
• Forwarding Domain: The Forwarding Domain (FD) class models the topological component that represents a forwarding capability that provides the opportunity to enable forwarding (of specific transport characteristic information at one or more protocol layers) between points.
• FC Route: Each instance of an FC Route class models an individual route of an FC. The route of an FC object is represented by a list of FCs at a lower level with the implicit understanding that unmodeled link connections are interleaved between the lower level FCs.
• Link: The Link class models effective adjacency between two or more ForwardingDomains (FD). 
• LinkPort: The association of the Link to LTPs is made via LinkPort. The LinkPort class models the access to the Link function. 
• LTP: The Logical Termination Point (LTP) class encapsulates the termination and adaptation functions of one or more transport layers represented by instances of LayerProtocol.

ONF CIM reference:

The wan descriptor application for general scenario is shown as below diagram:

Notice: 

XC: Cross-Connect (TMF513_v3.1_070314.pdf 4.1.17  Cross-Connect), A Cross-Connect (XC) object shall represent a FC within a Network Element (NE). 

LC: Link Connection (T-REC-G[1].805-200003-I!!DOC-E.doc 5.2.2.1 Link connection), A link connection is capable of transferring information transparently across a link. It is delimited by ports and represents the fixed relation between the ends of the link. A link connection represents a pair of adaptation functions and a trail in the server layer network. LC is FC (TR-512.TM_OnfCoreIm-TerminologyMapping.pdf page 7)

There is a special resource class not shown in the class diagram above, that is specification. The classes of Wan Descriptor shown above are abstract, we could use them to describe any wan scenario with specify specification which has the specify parameters for the scenario. For example, we could use overlay vpn specification an FC to describe overlay vpn. All specify specification classes are derived from specification base class which is shown as below diagram: 

The specify specification class will be consumed by specify Direct Graph in SDN-C. As we could import specification class in SDC and import DG in SDN-C dynamically, new wan scenario could be taught to ONAP after version release.

Use Case Example

Take the ONAP R1 VoLTE use case as an example. Volte wan contains overlay vpn and underlay vpn, both of them could be described as a FC. And the relationship between overlay vpn and underlay vpn could be described by FCRoute and LinkConnection.

The class diagram of ONAP R1 VoLTE use case shown as below:

Wan descriptor node type definition example: WAN_type_definition.yaml

Volte Wan configuration node type definition example: WAN_Volte_wan_configuration_definition.yaml

Volte Wan template example: VoLTE_WAN_template.yaml

Class Dtail

• Wan Design Time Information Model
• Wan Run Time Information Model
• Wan Design Time Data Model