# A Dual-Connectivity Mobility Link Service for Producer Mobility in the Named Data Networking
## 1 Introduction  
The Internet of Things (IoT) environment in which various objects are connected through wired and wireless networks to collect, process, exchange, and share information has become an important technology for building a smart city due to the development of cyber-physical system technologies. CPS collects and analyzes information in the physical world through various smart sensors, and immediately applies the results to the physical world through an actuator, so that the cyber world and the physical world are closely connected and cooperate. At this time, the role ofthe smart sensor has been expanded to be able to move freely, not just a device placed in a fixed position, and another service could be provided through the mobility of these IoT devices [1]. In this Internet of Mobile Things (IoMT) environment, each IoT device could operate simultaneously as a provider and consumer of information, Named Data Networking (NDN) [2; 3], which is a new promising Internet architecture that is currently being used to build a distribution network, is suitable for these IoMT environments [4]. The Internet uses the location-based address and stateless forwarding paradigm, but NDN supports information-centric addresses and the stateful forwarding plane [5]. Consumers do not need to know the locations of the contents in which they are interested, because the consumer requests content by mentioning the content name to an NDN router. The NDN Router is then responsible for forwarding the consumer's Interests to the node where the content is stored. In contrast to routers for the Internet, NDN routers store some content, and pending content requests are stored in their caches. However, there are challenges associated with supporting producer mobility [6] in NDN. For example, as a producer randomly moves, it changes its NDN Access Router (NAR) in an unpredictable manner. This causes it to miss the delivery of Interests to the producer. If the producer is the sole owner of the specific content and the content is only stored with the producer, all the Interests for the content should be forwarded to the producer. In order to decide which NDN face should be used to forward an Interest for content to the producer, the NDN router refers to the Forwarding Information Table (FIB). The FIB table is generated by the NLSR routing protocol [7] on the NDN router. If the producer changes its NAR, the NDN router may choose an NDN face to deliver the Interest to a NAR that the producer was connected to in the past. Until the FIB is updated, Interests towards the producer will be delivered to the out-of-date NAR. There have been several proposals put forth regarding NDN producer mobility. These can be divided into two categories: anchor-based schemes and anchorless schemes. Anchor-based schemes [8; 9; 10; 11; 12] introduce an anchor (or a rendezvous server) to track the current locations of contents. The anchor stores the binding information for content and its location. The anchor usually interacts with the mobile producers to maintain updated binding information. Anchor-based schemes resemble the Home Agent, as defined in [13; 14]. However, it causes suboptimal routing problems and signaling overhead. In anchorless schemes [15; 16], mobile producers send special announcements to the previous NAR whenever they change the point of attachment. Therefore, all NDN routers on the signaling path must understand the meaning of the special announcements. Consequently, the anchorless schemes modify the NDN router architecture so that it can handle both ordinary Interests and Interests that require redirection. This may break the simple architecture principle of NDN [17]. In this paper, we propose an anchorless NDN producer mobility scheme. The proposed scheme neither modifies the current NDN router architecture nor announces the producer's movement to the NDN nodes. It treats the exchange of the <Interest, Data Packet> pair as a transaction.