## 2 NDN Background and Related Work
### Related Work
#### 2.3.2 Anchor-Based Approach  
To support producer mobility, a solution proposed by the NDN Research Labs [17], denoted as \"Kite\", involves using a Rendezvous Server (RVS) as an intermediary to facilitate communication between consumers and producers. This strategy involves publishing the producer's content under a reachable RVS prefix. When the producer changes PoA, it sends a Trace Input (TI) to the RVS. In response, a Trace Data Packet (TD) is sent back to the producer, which follows the same path as the TI. When intermediate routers receive the TD, they create a FIB entry for the MP using the data name extracted from the TD and the face from which the TD is received to create a hop-by-hop path between the MP and the RVS. Thus, when the consumer wants to fetch data from the producer, it sends Input initially to the RVS. Subsequently, the RVS forwards this Input towards the MP along the path that was created earlier during the handoff process. However, the Kite scheme introduces two main drawbacks. Firstly, it brings a large signaling overhead due to the necessity of maintaining the path to the MP in the Trace FIB table. Secondly, frequent handoffs by the MP can lead to the \"stale path\" problem, where outdated path information results in increased packet loss. The authors of [18] proposed a redirection-based strategy to support content source mobility in Content-Centric Networking (CCN) to reduce routing overhead caused by updates to the router's FIB. When a content source moves to a new PoA, it sends a special Input to its home domain router, which acts as a home agent in the context of mobile IP. This Input contains the prefix advertised by the new PoA. Subsequently, when the home domain router receives a consumer's Input, it encapsulates it within a new Input using the prefix of the new PoA as the content name. This encapsulated Input is then forwarded to the content source based on the content name associated with the new PoA. However, this strategy suffers from the path stretch problem, as all Inputs must pass through the content source's home domain to reach it, potentially increasing latency. Additionally, Input encapsulation introduces additional complexity to the CCN protocol, making it more challenging to implement and maintain. [PERSON] et al. [19] presented an on-demand Anchor strategy to support producer mobility. In this strategy, when the MP switches to a new PoA, it sends an Input (mobility update) containing its content name to an immobile Anchor router, establishing a trace path with the Anchor. As the consumer's Inputs reach the previous PoA of the MP, rather than being dropped, they are redirected to the Anchor router. Subsequently, the Anchor router forwards the Inputs toward the producer's new location. However, this strategy does not specify Anchor placement in the network, potentially leading to path stretch due to the consumer's Input redirection through the Anchors. The work described in [20] proposes a pulling-based strategy, denoted \"ProPull\", to support producer mobility for real-time content delivery. This strategy aims to provide the best possible quality of service for consumers by ensuring uninterrupted multi-media transmission during producer mobility while minimizing signaling overhead costs. The ProPull strategy achieves this by pulling Inputs from the producer's old PoA to the new PoA. When the producer predicts a handover, it sends a special Input to the current PoA to obtain its prefix. Once connected to the new PoA, the producer communicates with the old PoA by exchanging special messages called Propaganda Inputs and Propaganda Data packets. This communication establishes a temporary forwarding path between the old and new PoA, ensuring that consumer Inputs are pulled efficiently to the producer's new location. However, the ProPull strategy introduces high signaling overhead due to exchanging Propaganda Inputs and Propaganda Data packets during each producer relocation.