The demand for mobile data is ever increasing and is causing huge stress on cellular networks. Upgrading the capacity of the cellular network is an expensive and time consuming process, and the demand does not seem to slow down. The idea is to offload mobile cellular subscribers to the wired xDSL connections. This project attempts to design and implement an innovative and cheap solution by utilising the spare capacity of the xDSL connections. Doing this introduces four important issues: Network Integrity, Quality of Service, Authentication, and User Identification.
Network Integrity
Network integrity is important to ensure the privacy of both the xDSL subscriber and the mobile subscribers. This is achieved by creating a separated WiFi instance for the mobile subscribers and adding a series of strict firewall rules. Various vulnerability scans have been performed to test the implementation, and they show no signs of security issues.
Quality of Service
QoS is a necessity to ensure that the xDSL subscriber’s paid service is not degraded by the implementation. Several QoS mechanisms are implemented, and traffic identification for each network is applied through port translation. This enables Telenor to apply QoS on their side of the network for downstream traffic. Measurement results shows that upload QoS can not always be ensured in cases where the wireless medium is congested. Download QoS should in theory be ensured when QoS is applied on Telenors side, as long as the bottleneck is on the xDSL link and not the wireless medium.
Authentication and User Identification
Only Telenor mobile subscribers must be able to connect to the new WiFi instance, and the data of each individual user is required to be logged according to the Danish laws of data retention. A RADIUS server is implemented to authenticate and log subscriber information. To log the correct data to the specific user, traffic identification is applied through port translation. Various tests have been made to make a proof of concept.