Fiber is becoming an increasingly valuable asset for mobile operators, supporting quad play services, small cell backhaul and Cloud-RAN fronthaul. Carriers, infrastructure owners and network-as-a-service (NWaaS) providers are racing to expand their networks and this is driving mergers and acquisitions in established and emerging markets, including a flurry of activity in the US where telcos need to strengthen their position against cablecos, both in access and in backhaul. Verizon acquired XO Communications earlier this year, gaining its fiber and access to valuable high frequency spectrum. Now CenturyLink has emerged as the surprise buyer of Level 3 Communications – which had been linked with AT&T and Comcast – while two fixed-line ISPs, Windstream and Earthlink, are to merge in a $1.1bn…