A Diffserv Transport Network to Bring 3G Access to Villages in the Amazon Forest


Author Javier Simó-Reigadas, Universidad Rey Juan Carlos.

Since their conception, IP networks have been generally used under the best-effort paradigm. Then, several QoS-aware IP network architectures were proposed in the last two decades by the IETF and other actors, being DiffServ the most successful, and modern network technologies covering layers 1 and 2 such as ATM, Ethernet, WiFi or WiMAX have included mechanisms for traffic differentiation and some support for QoS. However, it is still uncommon to find a scenario were a QoS-aware network architecture such as DiffServ is adopted and the entire implementation is simple enough to be fully understood by undergraduate students.

This case study helps the student to understand what problems arise in an IP network when several terminals that need QoS guarantees share an IP infrastructure, and how the DiffServ architecture helps to solve the problem. Moreover, a practical implementation of queuing disciplines in the network nodes will be proposed. The student will learn how a simple embedded computer with Linux may become a DiffServ router, and how this can be applied to propose an appropriate communications solution for rural deployments in developing regions. This case study is based in the TUCAN3G project, a FP7 research project that aims to propose a low-cost solution for 3G coverage in rural areas of developing countries (TUCAN3G, 2013). The student will firstly receive a theoretical session about the fundamentals. Then, students will have to work on a problem resolution activity in which the theoretical concepts must be applied to a well defined scenario.


  • The student will learn how DiffServ contributes (qualitatively and quantitatively) to make an IP network QoS-aware.
  • The student will learn how to identify QoS limitations in an IP network, and to propose appropriate actions to improve the overall performance.
  • The student will learn how to apply well-known queuing disciplines to implement the per-hop behaviour (PHB) desired for a particular case in a DiffServ domain.
  • The student will learn how QoS-aware IP networks based on WiFi and WiMAX may become a key solution for the deployment of low-cost communications infrastructures in rural areas at developing regions.


The following learning activities will be proposed:

  1. Theoretical session: 2 hours class on QoS (Quality of Service), the DiffServ architecture and the implementation of a basic DiffServ solution. The case study will be presented as a means to understand the detailed performance problems to be tackled in an IP network in which certain traffic classes require QoS guarantees. Prior to this session, the student will have to read basic materials on QoS, DiffServ (referenced below) and queuing disciplines, or to have received a basic training on those subjects. It is also advisable for the students to read the context of this case study in advance.
  2. Problem resolution activity: the students will be organized in working groups and will be presented a communications problem based on the same context explained in the theoretical session. Several basic communications elements and techniques will be proposed, and each group will have to discuss about the right way to solve the problem and define all the details for the implementation of the network. The outcome will be a technical report produced by each group.