## 4 Implementation of Proposed Architecture
### Centralized MEC/Cloud Orchestrator
#### 4.2.2 Sequence Implementation  
There are two main steps for the end-user to obtain the Private/Local Telecom Operator's services. The first is subscription registration, and the other is application deployment. Figure 6: Illustration of the Centralized Type of an MEC/Cloud Orchestrator. The implementation detail of the proposed centralized sequences is shown in Figure 7. First, the end user needs to access the GUI view using a registered account. Here, if the user obtains access with a registered account, they receive a success message in GUI view. However, if the user accesses with an unregistered account, they receive a failure message response. The above sequence is a basic rule for blocking unauthorized access using a registered account in Figure 7a. On the other hand, the sequence in Figure 7a acquires information on the cloud and multiple MECs regularly, which is a different sequence from user access. An authentication session can be established because the key authentication format is distributed in advance. As monitored by the polling method, the status of the physical/logical information of the resource area (computing, network, storage) secured in advance on the cloud system is confirmed. Similarly, the status of the physical/logical information of the resource area that can be used as MEC held by each Private/Local Telecom Operator is checked. The database inside the Orchestrator function is updated based on the information learned here. Although Figure 7a exemplifies the polling method, of course, a notification format in Syslog/Trap format is conceivable. Regarding the deployment resource space, as it is assumed that the Cloud Owner holds MEC/Cloud Orchestrator, the application deployment computing resource in the cloud can be changed by the MEC/Cloud Orchestrator according to the usage status of the application. The resource area in MEC can be determined/changed according to the contract with the Private/Local Telecom Operator. Next, the end user describes the sequence of registering a subscription based on the access information. The end-user makes a subscription registration request. Here, the end user needs to input the Private/Local Telecom Operator service data and select the range of use and the type of service. The Orchestrator GUI then receives a registration request with the GUI function and makes a service registration request to the Orchestrator function. The Orchestrator function confirms whether the resource area on the MEC side is open for the received request. If there is no problem, it provides a successful notification. Otherwise, if the resource area is insufficient, a request is made to the Private/Local Telecom Operator to update the contract in order to obtain the additional resources. The MEC side is notified of the possibility that the resource area is insufficient. The service requirements (latency, cost, etc.) are not positively required. The Orchestrator notifies the end user that the processing performance is not guaranteed in this case. When further subscribing, it is necessary to consider the priority compared to other end users. Second, the application deployment sequence is shown in Figure 7b. The end-user starts the application deployment based on their subscription. There are three designs as an application deployment method, as follows: (1) specific application deployment method; (2) cloud cached content of application specified in the cloud; and (3) computing resource reservation method. The deployment method in (1) involves deploying a basic application on a virtualization platform through VIM (Virtualized Infrastructure Management). Method (2) is an intelligent method that generates cache content based on the access usage log information of cloud applications that end users have used thus far, and deploys it on MEC. This method is possible because the Cloud Owner holds the MEC/Cloud Orchestrator. Regarding (3), unlike (1) and (2), it is a method of reserving computing resources in advance.