# Multi-Device to Multi-Device (MD2 MD) Content-Centric Networking Based on Multi-RAT Device
## 5 Conclusions  
This paper has proposed a method of transmitting and receiving a device's information using Bluetooth Beacon in order to solve the issues faced in an MD2 MD CCN environment in which mobile devices actively search for and connect to nearby devices, configure a network, and then connect to the device that owns the content, so as to enable its retrieval. A performance evaluation of the proposed method was also performed on a testbed. It is possible to rapidly connect to a device satisfying the user's requirements without any unnecessarily repetitive processes, through the selection of the optimal device based on the detailed information received using the proposed method. Moreover, application scenarios for efficient content identification and delivery, as well as network configuration between devices in an environment in which multiple mobile devices coexist, have been proposed.  
The proposed method offers the advantage of enabling fast and efficient connection to the optimal device, and can also be extended to various other areas. However, it is subject to limitations in that there is a need for an additional Bluetooth interface and the issue of possible interference with the WLAN signal. However, these are not significant limitations because most mobile devices support Bluetooth along with WLAN, while Bluetooth Beacon was designed with an emphasis on low power consumption using BLE. Moreover, Bluetooth minimizes interference through the adoption of a frequency-hopping technique which rapidly transmits small packets through multiple channels.  
As a result, the proposed method and application scenarios offer the advantages of enabling efficient content identification and delivery in a content-centric IoT environment in which multiple mobile devices coexist. Furthermore, an MD2 MD CCN environment based on these methods and scenarios offers various benefits to both users and the telecommunications company. The users can transmit and receive content by configuring a network with devices only, even if there is no Internet access or additional servers. The telecommunications company can reduce the network overhead and simplify the structure since the mobile devices actively search for and communicate with nearby devices.  
The MD2 MD/MCCN/Heterogeneous networking-based multimedia content transmission technology proposed in this research shows better performance than the existing research. Moreover,  
Figure 17: Average lengths of time consumed by request/response.  
in contrast to the existing research which has produced only theoretical results, the result of this research was developed in a form that can be operated on an actual network.  
Our laboratory is currently working on the openwincon project, which is based on open-source software for anyone to create and operate a mobile communication/wireless network, and also working on the GOTHAM project which supports networking and multimedia transmission in an integrated network. Open-source software resulting from the two projects has been released on GitHub [33; 34].  
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2015R1D1A1A01059147).  
All the authors contributed equally to this work. All authors read and approved the final manuscript.  
The authors declare no conflict of interest.