## 3 NDN Overview and Its Benefits in WSNs  
The idea of NDN was initially proposed by [PERSON] in [20] and is based on a content-centric networking model. The proposed architecture presents a robust and efficient communication model which is built on Interest and Data packets. The consumer node forwards the Interest packet to retrieve his required content object. On receiving the Interest packet, the corresponding nodes (if they have the requested content in cache) deliver the desired content to the requester by following the chain of PIT entries of the nodes in the reverse path to reach the requester node. The detailed NDN communication process is visualized in Figure 1.  
Each NDN node carries the following Data structures: (1) Pending Interest table (2) Content store (CS), and (3) Forwarding Information Base (FIB). The Interest and Data packet forwarding is carried out by consulting the PIT, FIB, and CS. The PIT table records the forwarded Interests, the CS caches the incoming Data packets to fulfill future requests, and the FIB relays the Interest packet(s) towards the potential provider node.  
The core features of NDN, such as in-network caching, requests aggregation, and content level security, match with the WSNs applications and efficiently handle the underlying constraints. Some of the benefits that NDN can offer in the domain of WSNs are defined as follows:  
* **Ease of application development:** In WSNs the consumer usually demands the Data or content regardless of the location or identifier of the producer node. The consumer application may demand the Data in an information-centric manner irrespective of the physical location of producing entity.
* **Data availability:** The enchanting in-network caching feature of NDN overcomes the problem of information loss due to unavailability of the node which may happen due to several uncertainties, such as battery depletion and sudden hardware or software failure in resource-restrained WSNs.
* **Ease of Data retrieval:** The consumer simply requests the content by issuing an Interest packet that carries the name of the desired content, whereas any receiving node which has already cached the requested content replies with the Data packet regardless of the actual producer of the content. In the network of a large number of wireless sensor nodes, the hierarchical naming provided by the NDN enables easier request/Data aggregation and accelerates the search and information retrieval time. Moreover, the name-based routing mechanism resolves the issue of address space scarcity which may arise in assigning the unique addresses to the huge number of WSN nodes.
* **Scalability:** NDN inherently supports scalability and allows multiple nodes to take part in the Data forwarding process. It greatly improves the quality of communication with an increase in the number of nodes in the given area via intrinsic forwarding procedures.  
Information-centric WSNs correspond to the category of WSNs which mainly focuses on information retrieval rather than establishing the point-to-point (P2P) communication setup between the objects. In this regards several efforts have been devoted to literature to provide seamless and efficient information sharing.