An evolutionary path for the evolved packet system

New architectural requirements appear with the evolution of mobile networks, such as the provisioning of multihoming or offloading. In general, this requires the design of ad hoc schemes on top of the EPS, which may be seen as an indicator of the need for a back-to-basics architectural analysis. This article analyzes the basic architectural principles of the EPS, and compares them with those of SDN and LISP. We then describe an evolutionary path for the EPS, by showing how, with slight modifications inspired by SDN and LISP, future mobile carrier networks could natively fulfill some of their flexibility and scalability requirements. The key design principles for that are: a generalized use of traffic flow templates (i.e., 5-tuple flows) for more flexible IP flow handling; a full decoupling of control and user plane for flexibility; and an on-demand (or pull-based) state setting at network nodes for scalability. Some examples are given to illustrate the thesis of this article.