# Mathematical Models for Named Data Networking Producer Mobility Techniques: A Review
## 3 Recent Mobility Techniques
### Rendezvous Technique  
In the context of rendezvous in NDN, the term \"topology situation\" pertains to the organization and interconnection of nodes, explicitly emphasizing the positions of Rendezvous Points (RPs). Rendezvous stations are centralized hubs facilitating efficient data interchange between content creators and consumers. Note that implementing RPs and their strategic positioning throughout the network is vital; hence, examining various methods for choosing RPs, such as proximity-based or load-balancing techniques, can influence the effectiveness of content retrieval. Comprehending the impact of the entire network structure on the choice and effectiveness of RPs is also significant for optimizing the rendezvous model. The forwarding mechanism in rendezvous governs transmitting material from producers to consumers through rendezvous stations. The process entails the methods via which data packets traverse the network, utilizing rendezvous sites to optimize the routing and delivery of content. It is essential to assess the efficacy of various forwarding techniques, such as direct forwarding, rendezvous-based forwarding, or a hybrid approach. An analysis of how these techniques manage the distribution of material, improve latency, and adjust to dynamic network conditions deepens our comprehension of rendezvous in NDN. The mobility parameters of handover in rendezvous refer to how the model handles the movement of producers or consumers throughout the network. This encompassesfactors such as the velocity of producer movement, the frequency of transfers, and the methods for ensuring uninterrupted content delivery during mobility events. The signaling cost in rendezvous refers to the additional expenses of transmitting control messages to manage RPs, facilitate handovers, and coordinate between producers and consumers. Assessing the efficiency of rendezvous in NDN requires a crucial evaluation of the signaling cost. Hence, efficiently reducing the additional costs related to signaling while guaranteeing the appropriate selection of RPs and good handover management is crucial for optimizing the model's performance. Examining the influence of signaling on network resources, latency, and scalability yields valuable information on the overall effectiveness of the rendezvous strategy. When examining the rendezvous model in NDN, it is crucial to recognize particular constraints and establish specific assumptions to define the extent of its suitability. The limitations include scalability, dependency on RPs, management of dynamic network conditions, security and privacy implications, stable RPs, predictable behavior of producers and consumers, sufficient network connectivity, centralized coordination, and a homogeneous network environment. Figure 5 illustrates that the rendezvous server technology uses a mapping system, like the current DNS, to segregate the control and data planes. The initial connection between the consumer and the producer is stored in the DNS in order to match their correspondence precisely. However, the process varies when a mobile consumer or producer saves the current DNS state, as the original router cannot transfer the data update to a new router position. In such cases, a rendezvous server is required to maintain the current state of the new location. Algorithm 1 outlines the rendezvous technique regarding a routing forwarding mechanism for producer mobility. The incoming customer interest is sent to the closest node in a queuing state. Assuming there is no packet loss, a NACK packet will be issued if the interest packet is not sent to the nearest node. Consequently, the producer will generate a NACK packet if the forward receives the interest packet. If there are no other loops to  
Figure 5: NDN rendezvous technique. submit for the next-hop node currently available, receiving a data packet from the consumer is necessary.