# IPv6 Convergence for IoT Cyber-Physical Systems
## 2 Background
### 5G Ecosystem Context
#### 2.1.1 Heterogeneous Networks  
Two key challenges involved in managing a dynamic wireless communications infrastructure involving mobile nodes are the increased computational load and network propagation delays. [PERSON] and [PERSON] investigated the challenge of quality of service (QoS)-based routing with incomplete network state information in 2001 [29]. They focused on mobile nodes without a fixed infrastructure interconnected by multihop communication paths with dynamically changing topologies. They summarised that guaranteeing QoS in such a network where nodes join and leave the network, and incomplete network state information exists, may be impossible if nodes are too mobile. In 2002, [PERSON], [PERSON] and [PERSON] developed a set of NS-2 simulation models and techniques mainly focusing on a sensing channel through which sensors detect targets, and provided detailed models for evaluating energy consumption and battery lifetime [30]. The concept of abstracting services or dataflow away from the underlying infrastructure in a wireless sensor network context was initially addressed in some detail by [PERSON], [PERSON] and [PERSON] in 2007 [31]. They proposed a global sensor network middleware supporting dynamic integration and management of distributed sensor networks and a virtual sensor which abstracts from implementation details. This virtual sensor concept is essentially a container with the ability to accept multiple inputs, produce one output data stream, and include all necessary metadata required for deploying and using it. However, this approach is high level; it uses eXtensible Markup Language (XML) to describe the sensors and Structured Query Language (SQL) to deal with query execution.  
In 2011, [PERSON] et al. proposed a platform-agnostic framework for integrating heterogeneous smart objects in the Web of Things [32]. Their framework consisted of four different hardware platforms, Arduino, SunSPOT, TelosB and iSense. The authors described the necessary steps required to make such a heterogeneous network interoperate, in the form of a software library, named mkSense, that enables their intercommunication. They describe the design and implementation of a software library that can be used for building \"intelligent software\" for the Web of Things. The authors focused on interconnecting different IEEE 802.15.4-based systems to create their heterogeneous sensor network. The first step was to set all the devices to 16-bit addressing mode, and to the same personal area network (PAN) ID and channel. Following this, they built a library for each of the devices we wanted to support, which were intended to care for on-boot device configuration involving resource initialization for IEEE 802.15.4 communication and exposing an application programming interface (API) for users.  
Our summary of this work is that without sufficient network state knowledge, the underlying algorithmic complexity involved in determining optimal routing strategies may be perceived as intractable, that is, NP-complete. In order for us to sufficiently address this challenge, guided assumptions regarding the network state and topology may be required to devise strategies within a constrained time window. It can be argued that adopting a converged IP approach for heterogeneous networks significantly reduces or potentially eliminates the problem of multiple siloed networks and inefficient use of combined networking resources as a result.