There are plenty of start-ups looking to ride the virtualization wave to penetrate the carrier space, but a recent stand-out has been Boston-based Rift.io, which came out of stealth mode with $16m in funding last week, promising an open source NFV platform by the end of this year. Its founders come from big names – Cisco, Starent, Juniper and 3Com- and the A round of financing is led by North Bridge Venture Partners, as well as various strategic investors. Its platform is called Rift.ware and the company hopes to use the open source route to achieve the kind of scale that could worry the larger NFV vendors. It will work with developers of virtual network functions (VNFs) to create an…