# Transparent CoAP Services to IoT Endpoints through ICN Operator Networks +
## 1 Introduction  
The Internet-of-Things (IoT) is anticipated to interconnect billions of smart objects and constrained devices that will generate an enormous amount of information. Cisco forecasts that there will be around 50 Billion IoT devices such as radio-frequency identification (RFID) tags, sensors, and actuators on the Internet by 2020 [1]. IoT is increasingly relying on data and information rather than on end-to-end communication, which could promote the adoption of an Information-Centric Networking (ICN) architecture [2]. The driving paradigm in ICN is that Named data is the central element of ICN communication. To achieve this, ICN introduces named content as a network primitive and provides in-network caching. ICN allows the user to retrieve a particular content regardless of any reference to the physical location of the content. However, considering IoT scenarios from an ICN perspective may raise challenges of a very dynamic and heterogeneous nature. First, the information exchangedin IoT environment is heterogeneous. During the last decade, many custom proprietary solutions have been developed and deployed in a multitude of the IoT use cases. However, the lack of interoperability among these solutions exposes a major challenge. Second, many of the IoT devices have limited battery capabilities and, therefore, the networking and computing capabilities of the IoT devices have to be energy efficient for long-life operation. Third, the ICN approach in IoT needs not only refactor the networking protocols and Internet applications [3]. This is because ICN introduces named data networking as a replacement of Internet Protocol (IP). ICN has no notion of host at its lowest level, i.e., ICN integrates content/service/host abstraction, name based routing, and in-networking caching as parts of the network Infrastructure. Such evolutionary changes to every network layer are an overwhelming barrier to the adoption of ICN. With this in mind, the POINT project [4] proposes an evolutionary approach to ICN adoption: an individual ICN operator uses network attachment points (NAPs) in order to translate legacy IP application traffic to ICN, i.e., the ICN network is transparent to IP endpoints. In this paper, we assume or target an operator network which runs ICN in its network core. Outside the operator network, the conventional Internet based on IP protocol performs communication between user endpoint and the Network Attachment Point (NAP) which is a gateway between ICN and IoT technologies. Our design approach connects IP based Endpoint through ICN. The user endpoint (UE) using legacy IP is oblivious to ICN. We called our solution which enables the legacy CoAP [5] and CoAP extensions to IoT devices through the ICN operator network so that the IP endpoints implementing only the core CoAP can benefit from the CoAP and its extensions by leveraging the multicast capabilities of the POINT architecture. We connected two converging, yet not totally compatible, issues: Information Centric Networking (ICN) and IoT specific communication protocols (CoAP handler) through the Network Attachment Point (NAP). The communication between IP endpoint and NAP is based on IP. Then, NAP performs protocol translation and forwards the data to other IP endpoint. The NAP which is close to a client is called client NAP (cNAP) and server side NAP is called sNAP. In this paper, we cover all CoAP specific communication scenarios through ICN. For this NAP does fine tune engineering in the whole system. The main goal of this paper is introducing CoAP for the ICN NAP that improves the IP-based CoAP service offering of the clean slate ICN operator network. The key idea of this architecture is that we target a single operator network which would like to improve its own IP-based services. Our approach enables the usage of the legacy CoAP and CoAP extensions, i.e., our system architecture allows for connecting existing CoAP protocols running on IoT devices without any modification.