## 3 Proposed Scheme
### Overview of Proposed SDPCACM Corresponding to NDN
#### 3.2.5 Inter-Domain Handover Use and Control Scenario  
When a consumer moves to a new node, i.e., alters the domain area and enters another area of a different domain, then, inter-controller (between controllers) communication is mandatory to carry out the transfer of the MC. Figure 6 displays an inter-domain handover operating case, where the MC transitions from AP-4 to AP-5 accessing data packets (A-H) from NAR-2 and NAR-3, both of which are controlled by different SDN controllers.  
The before and after handover procedure is the same as in the intra-domain handover handling scenario, but the method is different during the handover, as illustrated in Figure 5.  
Before handover: in an inter-domain handover handling scenario, such as when a user MC wants to watch a video, they first issue an interest packet and then the corresponding data packet is sent back to the MC and these data packets are stored in the CS of each intermediary router which delivers them [28]. Step 1: when the impending movement event is detected, the user, i.e., [PERSON], receives a control interest packet from NAR-2 through AP-4. The handover indication bit is then set to one by NAR-2, which also adds a handover field to the appropriate PIT entries. Following that, NAR-2 determines if a given PIT entry matches a data packet when it is received. The received data packet is cached by NAR-2 if the handover indication bit is set to one [9]. Step 2: meanwhile NAR-2 has sent the control interest packet that contains all this above information to the SDN controller-1. Therefore, the SDN has a clear scope of the state of the entire movement.  
During handover: as NAR-2 is aware of [PERSON]'s movement and has particular PIT entries, the specific data packets that come into NAR-2 are not forwarded to the CS and instead are only cached. In this way, packets are prevented from being lost on the route to the [PERSON]'s old location, which is AP-4 [30; 31; 32; 33; 34]. Meanwhile, NAR-2 sends a control interest packet (type: handoff initiation interest message) to SDN controller-1. Therefore, the SDN-1 has a clear scope of the state of the entire updated movement toward the NAR-3.  
Figure 6: Inter-domain handover supervision scenario.  
Step 3: in this scenario, the MC switches domains and enters another domain's territory, necessitating inter-SDN controller communication to manage the MC's travel. In this instance, it crosses over into another domain's territory and establishes a connection with NAR-3, which is situated near SDN controller-2.  
For illustration, a technique is applied, i.e., in the first phase the controller-1 in SDN makes an inquiry for the subsequent controller which is controller-2 to report the movement of the MC, which is from AP-4 to AP-5, and also forward the information. This leverages an updated routing table with appropriate FIB entries of the routers delivering this packet, thus triggering proactive caching actions on NAR-3. Therefore, NAR-3 actively initiates requesting and caching data packets previously stored in NAR-2 through the normal exchange of interest packet/data packet. In this way, NAR-3 proactively caches and receives the rest of NAR-2's contents.  
Completing handover: Step 4: when the MC is within range of NAR-3, i.e., the MC is within range of AP-5, it establishes a connection with NAR-3 and sends a handover complete message to NAR-3, who then resends the remaining data packets to the MC. As a result, the packet is transmitted in this manner from NAR-2 to NAR-3, where it is quickly received by the MC without any subsequent delay.