# Insights from the Experimentation of Named Data Networks in Mobile Wireless Environments
## 3 Integrating NDNs in Smart Cities
### NDN in the ATCLL
#### 3.3.1 NDN Configuration  
The NDN daemon is in charge of performing all the necessary setup of the NDN stack modules that implement the NDN architecture, such as forwarding and caching tables (PIT, CS, FIB) as well as verifying which physical interfaces exist on the device and installing an interface of communication between them and the NDN stack to allow for traffic routing using NDN packets as opposed to the commonly known IP. The components of these  
Figure 4: Deployment of NDN over ATCLL mobile communication units.  
modules can be configured via a control file which is analyzed by the daemon upon start, holding variables such as blacklisting of physical interfaces to be installed, among others.  
Similarly, the NLSR routing protocol [10] behaves in analogous fashion, being in charge of calculating routing tables for each node in the infrastructure, thus, establishing their neighbourhood and guaranteeing that every Interest packet arriving at the edge of the network via the wireless medium can be properly forwarded towards their destination through a suitable NDN face, which can be controlled upon initialization via a control file. While all nodes in the network that wish to maintain NDN communication must have the NDN daemon installed and running, only fixed nodes composing the infrastructure are required to have the NLSR protocol running in order to route NDN traffic, due to their initial static neighbourhoods. Moreover, only certain nodes will act as either Producers or Consumers. This behavior is introduced via applications, which are designed specifically with a goal in mind, such as asking for a specific file, and must include proper packet creation in the NDN format and successful connection to the NDN daemon installed on the node. These applications are in charge of locally managing the content to send back to Consumers, acting as a Producer, and manage the Content received, when acting as a Consumer, using the daemon as a process to communicate with the outside world.  
In its current state, the NDN platform does not intrinsically transmit traffic in the physical medium; instead, its network layer protocol makes use of the existing foundations set by IP which includes physical channels such as Ethernet wires and logical connections such as UDP or TCP tunnels over the existing Internet (Figure 5). To this extent, all communications between two direct nodes, as is the case with edge nodes and routers in the infrastructure, use UDP tunnelling to successfully route data (Interest or DAta packets) amongst them. On the other hand, when using the wireless medium, mainly between edge and mobile nodes, communications will take effect in a broadcast manner, in which all nodes will receive and transmit data without being directly influenced by its neighbours as expected from the case under study.  
Figure 6 details the messages exchanged between a mobile Consumer and a mobile Producer, and the operations performed on each network element, when different radio access technologies are used.