# Affordable Broadband with Software Defined IPv6 Network for Developing Rural Communities
## 4 Affordable Broadband Services with SoDIP6 Network  
This section addresses the research question of \"How does SDN and IPv6 network implementation contribute to service provider sustainability and affordable broadband services for customers?\"  
We evaluate the energy optimization in an SoDIP6 network from the experimental analysis by simulation, considering heterogeneous (wired and wireless) networks suitable to be deployed in rural communities. First, we summarize the features of the SoDIP6 network, then we present the energy evaluation of the SoDIP6 network with results and analysis. SDN and IPv6 are the two networking paradigms that will likely replace the existing legacy IPv4 networking system worldwide to avoid existing issues in addressing, routing, network operation, and management. The major benefit of SDN is its flexibility, programmability, and controllability, which could help to reduce the CapEX/OpEX of organizations [38] and encourages service providers to search for better options and attract them towards SDN. In summary, the benefits of transitioning to an SoDIP6 network are summarized as follows:  
* **Address space:** The larger IPv6 address space opens opportunities for scalable network design, growth of end users and smart devices. The existing Network Address Translation (NAT) solution and its associated problems with IPv4 networking will be avoided. * **Network operation cost:** A flexible and horizontally integrated programmable SoDIP6 network decreases the overall operation and administration cost. Removal of NAT reduces the network operation cost and saves significant annual revenue with increased efficiency of the network in a large scale. * **Quality of service (QoS):** While there is limited implementation in practice, the flow-level field of the IPv6 header provides spaces for researchers to introduce QoS aware networking operations and services [39; 40; 41; 42]. Better quality increases the reliability, and so encourages organizations to move to digital packet-based communication, such as voice over internet protocol, that may lead to more savings in the annual telephony expenditure. Similarly, the programmability and flexibility of SDN would help improve the quality of network services. * **Security:** Security threats and worldwide cybercrime cost people and businesses, a loss of more than 200 billion USD per year [43]. The built-in IP Security (IPSec) framework in IPv6 implementation can significantly improve the network security [44; 45; 46]. Similarly, programmability features in SDN enables the application of different security models and deals with several security challenges to avoid modern security breaches [47; 48; 49; 50; 51; 52; 53]. We consider an end-access ISP network consisting of wired and wireless customer premise equipment (CPE), switches and their associated links by developing a custom topology in a Mininet-WiFi emulator with an Open Daylight SDN controller over an Ubuntu virtual machine. Considering Figure 2, the end-access network newly deployed is enabled with SDN and IPv6. The SoDIP6 enabled end-access network topology consists of 14 switches (SDN switch: S0-S5, Edge Switch: E1-E5 and Wireless Access Point: A1-A3) and 8 CPEs (cpe1-cpe5 and sta1-sta3) including wireless stations. The end access gateway router is supposed to be a translator router that performs the translation of SoDIP6 traffic to Legacy IPv4 and vice versa. We also assumed that the ISP backbone network is not SoDIP6 capable. This means it has only legacy IPv4 supports. Hence, end access gateway can be treated as a customer side translator and the external gateway as a provider side translator. These are translator routers which perform IPv4 to IPv6 header translations and vice versa. Legacy IPv4 networking devices like switches and links run 24 h a day with peak energy consumptions, and so result in a higher energy bill annually. The beauty of an SoDIP6 network is that energy consumption can be optimized using dynamic scaling, adaptive link rate, and smart sleeping [54].