## 4 Methodology  
This proposal is based on the concepts of Inter-Domain Messaging (IDM) [41] and Virtual Quality-of-service Networks (VQN) [42]. IDM is a novel solution for transporting messages in a heterogeneous environment. IDM was designed as a general purpose protocol for providing a data transport service end-to-end, which is independent of any network technology or protocol. IDM uses its own addressing and routing mechanisms. The communication model is based on object invocations, which provide many valuable advantages, such as a full location transparency and the possibility of deploying specific application code in a very simple manner, even better performance when compared to traditional IP-based solutions. Although IDM adds overhead, it could be a more efficient solution in many cases because it is a cross-layer protocol.  
VQN is an overlay network that uses IDM as a basis. It is implemented as a distributed application using object-oriented middleware for distributed systems. The original idea for the VQN model is to develop a mechanism that provides performance with Quality of Service (QoS) to a network that naturally does not have this structure, but its usefulness is not limited only to operations that are related to the network itself; it can also be used to provide additional functionality related to the application, such as information processing, semantic collaboration, and others.  
VQN and PIN have intrinsic capabilities for dynamic adaptation to network conditions. A feedback mechanism could be implemented in order to dynamically adjust Quality-of-Service (QoS) or Quality-of-Experience (QoE) for an specific user at the destination node. A feedback mechanism may be included as part of the PIN mechanism and make all the necessary QoS/QoE adjustments based on the feedback line. VQN has already several mechanisms (_i.e.,_ fuzzy logic and forecasts) that may be helpful when implementing this feedback mechanism.  
Notably, the IDM/VQN routers are virtual. Commercial (physical) routers are usually far from the reach of the distributed applications user. In most cases, they are dedicated to running specific protocols to provide an efficient forwarding process, and it is not possible to use them to deploy specific applications code. IDM/VQN makes deployment feasible and, thus, opens the possibility of implementing a PIN in a real environment (Figure 1).  
The code deployment process is dynamic and for a real implementation it is based on ZeroC IcePatch2 deployment capabilities for secure replication of a directory tree. The server manages the file system directory containing the software to be distributed to the clients. The server transmits (Figure 2) the files to the client, which recreates the data directory and its contents on the client side, replacing the old files with the new ones. IcePatch2 transfer rates are comparable to File Transfer Protocol (FTP).  
Figure 1: An IDM/VQN inter-network.  
Figure 2: Code deployment process.  
Our proposal is to use the IDM/VQN platform to implement PIN, taking advantage of all of the features mentioned above (transparency, deployment, and performance) and others. The processing logic that depends on the application is deployed to the routers as an implementation of distributed objects. PIN is integrated into the IDM/VQN infrastructure in a very natural way because the routers themselves and all of the other services are also distributed objects. Every IDM/VQN router is capable of implementing PIN functionalities, either as a part of the semantics or the network sublayer or even as a combination of both (Figure 3).  
Initially, three PIN functionalities are considered for the model: pre-processing, simplification of information, and information enrichment. These features can be upgraded and supplemented as the model evolves.