Massive　MIMO　(mMIMO)　is　a　technology　with　high　potential　in　future　5G　radio　access　networks　(RAN).　As　a　crucial　feature　in　mMIMO,　beam-forming　provides　a　remarkable　enhancement　for　the　wireless　transmission.　However,　beam-forming　introduces　extra　wireless　resource　and　fronthaul　bandwidth　consumption　for　utilizing　multiple　antennas　to　transmit　the　same　data.　Moreover,　this　problem　will　be　highlighted　in　the　multicast-service　beam-forming　because　more　identical　data　will　be　transmitted　in　networks.　In　this　paper,　we　focus　on　the　entire　resource　consumption　of　a　single　cell　for　the　multicast-service　beam-forming　in　next-generation　RAN　and　propose　a　flexible　wavelength-division-multiplexing-based　fronthaul　to　support　the　high-capacity　and　resilient　transport.　A　mixed-integer　nonlinear　programming　formulation　and　two　heuristic　algorithms　are　developed　to　minimize　the　utilized　optical　bandwidth,　radio　resource　blocks　and　antennas.　Simulation　comparisons　are　performed　among　different　resource　allocation　strategies.　Numerical　results　demonstrate　that　our　strategies　can　efficiently　reduce　the　total　resource　consumption.