## 4 Solution of Requirements and Inspection Methods
### Open-Flow Proxy Construction
It aligns virtual ports with the appropriate VLAN tags, facilitating the SD-WAN controller and OpenFlow switch to attain virtualization devoid of any requisite modifications, as delineated in Figure 25, a flowchart of the virtual port module. Pursuant to the control messages delineated by the OpenFlow Protocol, the packet fields undergo individualized processing. Within the packets transmitted from the native OpenFlow Switch to the SD-WAN controller, the port number consistently designates the port linked to the GPON OLT, accompanied by the VLAN Tag stipulated by the OMCI specifications. In order to realize the aim of the GPON SDN virtual switch, this module revises the port number field in the packet to denote the virtual port number corresponding to the VLAN tag. This modification enables the SD-WAN controller to disregard this mechanism, perceiving the GPON as a customary OpenFlow switch, and furthermore, meticulous attention is dedicated to managing the port state control messages in the port modification- and multi-port-related OpenFlow instructions. Figure 24: Status diagram of the control channel module. The ports established and interrogated through the SD-WAN controller should pertain to the tangible ports of the ONU. Consequently, an amendment is imperative to interrogate the pertinent configurations of the OMCI physical ports from the OLT management module, and the outcomes are relayed back to the SD-WAN controller. 3. Traffic Management Module  
In the commencement of the GPON SD-WAN virtual switch, this module engages with the ONU Management API. It oversees the activation and disconnection statuses of ONU devices to disseminate OpenFlow port status messages. For ONUs that have concluded ranging, this module institutes a traffic channel, autonomously discerning a VLAN tag as the virtual port number. Furthermore, upon the receipt of signals indicating ONU deactivation or disablement, it relinquishes the VLAN tag. In Figure 26, the operational chronology processing of this module is delineated. Figure 26: The operational chronology processing of traffic management. Figure 25: Flowchart of the virtual port module. The reception of notifications pertaining to alterations in ONU devices by the control channel management module invokes this module to undertake the governance of VLAN tags and the initiation of traffic channels. In practical terms, strict adherence to the GPON OLT and GPON ONU devices, in accordance with the ITU-T G.984 specifications, is meticulously upheld. The configuration and commencement of GPON OLT and GPON ONUs are orchestrated through the OLT network management system software. This expedites the provisioning of GPON network services, as illustrated in Figure 27.  
Following the execution of the OpenFlow proxy, it accommodates connections from the pre-established OpenFlow switch. In consonance with the exposition in Section 4.1, pertinent data fields undergo modification, and the refined information is transmitted to the SD-WAN controller. Subsequently, upon the ONU completing registration with the OLT, the configuration for VLAN is consummated, establishing the GEM connection. Concurrently, port status control messages are dispatched to the SD-WAN controller, appraising it of the commencement of the virtual port activation. Upon the advent of the packet, initially transmitted from the ONU side and arriving at the OpenFlow switch, the OpenFlow proxy, harnessing the VLAN tag within the L2 packet header, transmutes the source port in the packet in control command to the virtual port number of the GPON virtual switch. It then conveys this directive to the SD-WAN controller to facilitate the packet in control command for the GPON virtual switch. Likewise, as the algorithms of the SD-WAN controller discern routing rules, the proxy can transfigure the virtual port number in the data flow entry into a physical port number that the OpenFlow switch can adeptly manage. It judiciously appends the accurate VLAN tag, crafting a data flow in accordance with the GPON virtual switch.