## 3 Proposed Solution
### Forwarding Strategy
#### 3.2.2 Consumer Interest and Producer Data Packet Forwarding  
(1) Consumer Input Forwarding: When a consumer wants to request content, it sends an Input that typically includes the name of the desired content. In the case of our proposal, the Input also includes the X, Y, and Z coordinates, initialized with negative values by default. Upon receiving the Input, each intermediate router checks if the Input has non-negative coordinates. If so, the router forwards the Input using the location-based forwarding strategy. If not, the intermediate router performs a name-based longest prefix match lookup in its FIB to compare the Input content's name with the content names stored in the FIB entries. According to this comparison:  
If a match is found for the content name in one of the FIB entries, then the router determines the next-hop interface based on the information stored in the FIB entry, allowing the Input to be forwarded directly towards the producer without involving the Anchor. For instance, in Figure 3, the path of the Inputs of consumer 3 (steps 1) to the producer before handoff is: consumer 3 \(\longrightarrow\) PoA \(\longrightarrow\) R3 \(\longrightarrow\) R2 \(\longrightarrow\)R1 \(\longrightarrow\) PoA \(\longrightarrow\) producer. If no matching is found for the content name in the FIB entries, in this case, the longest matching prefix will be the prefix of the Anchor, and the Input will then be forwarded toward the nearest Anchor using the appropriate interface (e.g., Inputs of consumer 2 (steps 1 and 3) in Figure 3). When the Anchor receives the consumer's Input, it checks its FIB entry associated with the producer's data name. This entry contains two important pieces of information: (1) producer's location: this includes the X, Y, and Z coordinates of the producer retrieved previously through the CP or the predicted location coordinates after handoff updated by the RP packets; (2) Outgoing Interfaces: this information specifies the interfaces through which the consumer's Input should be forwarded. If an Outgoing  
Figure 2: Mobility management scenario: The MP sends the CP packet when it connects to the network for the first time (step 0). The MP send the RP packet prior to handoff (step 2). Interface is found, meaning that the path between the MP and Anchor has been created before the reception of the Input, then the Anchor and all intermediate routers along the path use the appropriate interface. If no Outgoing Interface is found, the location-based forwarding strategy is used to determine the appropriate interface. In this case, the X, Y, and Z of the Input coordinates are updated with the producer's location coordinates stored in the FIB entry, and each intermediate router along the path between the Anchor and the MP uses the location-based forwarding strategy to select the next Face to forward this Input (e.g., in Figure 4, the path of the Inputs of consumer 1 to the producer after AnchorB is AnchorB \(\longrightarrow\) R6 \(\longrightarrow\) R4 \(\longrightarrow\) PoA \(\longrightarrow\) producer). The forwarding process of the consumer's Input is detailed in Algorithm 1. (2) Producer data packet forwarding: when the producer receives the consumer's Input, it responds by sending a Data packet that follows the same path as the Input in reverse. Each intermediate router along the path uses the information stored in its PIT to forward the Data packet back to the consumer. Additionally, to reduce the computational burden of calculating distances for every Input in location-based forwarding, each intermediate router along the path between the producer and the Anchor creates a FIB entry upon receiving the producer Data packet. This FIB entry includes the name of the MP's data and the incoming Face from which the Data packet was received (e.g., in step 3, a FIB entry for the producer's content name is added to R4 after handoff, shown in Figure 4).