## 2 NDN Background and Related Work
### Related Work
#### 2.3.1 Anchor-Less Approach  
In the Anchor-less approach, managing producer mobility is achieved without the assistance of a specific node in the network. Various strategies are proposed to ensure the effective delivery of Inputs to an MP. These strategies may involve dynamically updating the FIB tables after a producer's handoff, caching the producer's content on a neighboring router before the producer's handoff, or employing an optimal broadcast to reach the MP.  
[PERSON] et al. [11] proposed a solution that involves the MP broadcasting a special Input (mobility Interest) throughout its new location. This Input carries the producer's location prefix information, which is used to update the FIB tables of routers within the producer's domain. Additionally, if the producer and consumers are located in different domains, the mobility Interest message is also used to update the FIB tables of routers in neighboring domains.  
The scheme outlined in [12] introduces a forwarding strategy designed to support producer mobility within NDN-IoT. In this scheme, each PoA continuously sends periodic Inputs to monitor the status of all attached sensors. When the PoA does not receive a response from a sensor, it sends a Recovery packet to remove the forwarding information associated with this sensor from the routers along the path between the producer and the consumer. Upon detecting the connection of a new sensor, the PoA sends a Recovery packet with the aim of creating a new FIB entry leading to this sensor. This Recovery packet is forwarded to the consumer using the longest prefix match method.  
[PERSON] et al. [13; 14] proposed \"MAP-ME\", a solution for supporting producer mobility in real-time communication by dynamically updating the FIB table in minimal routers in the network. In [13], when the MP changes the PoA, it sends a special update Input from the new PoA to the old PoA to update the router's FIB along the path between the new and old PoA. A new variant of the MAP-ME scheme was proposed in [14] to address the producer micro-mobility, which includes an additional protocol named \"Notification/Discovery\" to alleviate the issues of Input update dropping or late updating of the FIB due to network latency, which can be lead to an increase in packet loss. An Input notification is left by the producer at the old PoA to redirect the future consumer's Inputs through a broadcasting method until they meet the path toward the producer. A significant shortcoming of MAP-ME is it suffers from a triangular routing problem. It is worth noting that MAP-ME is related to topology-based methods.  
The scheme proposed in [15] focuses on supporting producer mobility in NDN by leveraging the in-network caching feature. The main idea of this scheme is to predict the next location of an MP and proactively cache the most frequently requested data in the router nearest to the consumer before the producer's handover occurs.  
The work described in [16] presents a scheme designed to reduce the delay and minimize packet loss caused by producer mobility in real-time remote health-monitoring systems based on NDN. The main idea of the proposed scheme is to register the MP in both the current PoA and the nearest PoA. In this way, the MP establishes connections and maintains a presence in the network even when moving between different PoAs. However, it is worth noting that inter-AS mobility brings a large signaling overhead since the proposed scheme uses a broadcasting forwarding strategy to locate a producer each time it crosses between autonomous systems. Furthermore, registering a large number of MPs with multiple PoAs can lead to a significant increase in the size of FIB tables at PoAs.