Towards an Open Mobile Core

In the ongoing evolution of mobile networks, a key emerging focus is on "openness": disaggregation to enable multiple vendors. The obvious example of this is OpenRAN, a movement to open the traditionally-single-vendor RAN, to multiple vendors. However, despite the clear benefits that this approach has brought to the RAN, there has been little interest in applying this philosophy to other parts of the mobile network such as the mobile core. We argue that applying the philosophy of openness to the mobile core will result in significant ecosystem improvements to both mobile network operators and governments. In addition, we identify the key challenges for an "open core", formulate a set of criteria for evaluating openness of core designs, and assess current alternatives with respect those criteria.