Flexgrid technologies enabling BRAS centralization in MANs

Abstract

In an evolutionary metro-regional area network (MAN) scenario, targeting the centralization of the broadband remote access server (BRAS), flexgrid technologies can be suitably tailored to be applied. We investigate their applicability, proposing network architecture and data plane solutions to improve the spectrum and network efficiency, while reducing CapEx investment. We first describe the MAN scenario evolution and the envisioned solution based on flexgrid for supporting BRAS centralization. Then, we define the network design problem, propose a solution, and use that to design a realistic regional network (region-A of the Telefonica Spanish network), identifying the transmission requirements for such a representative case. Subsequently, flexgrid data plane solutions are presented, focusing on the design, numerical validation, and experimental assessment of a sliceable bandwidth variable transponder based on orthogonal frequency division multiplexing. We propose an architecture able to meet the identified requirements, supporting flexgrid connections of up to 50 Gb/s per flow over a six-hop path of 545 km. Furthermore, an alternative scheme for the uplink is given and experimentally demonstrated in a four-node photonic mesh network. Finally, the techno-economic viability of the proposed solution is evaluated in comparison with current practice solutions.