Network functions virtualization (NFV) represents a major inflection point for telecom, and while it hasn't changed the world yet, 2015 saw the telcos and vendors setting the groundwork for some serious changes. Whether they lead NFV development directly or head up major networking companies, the following people are the major NFV and telecom influencers we tracked this past year.

Margaret Chiosi is one of the most vocal service-provider executives in NFV. A distinguished network architect at AT&T Labs, she is a regular spokesperson for AT&T’s Domain 2.0 initiative, which is bringing newer vendors into its fold. She’s been very active in open source groups such as the OpenDaylight Project (ODL) and took a leadership role in the creation of OPNFV last year.

Axel Clauberg, vice president of IP and optical with Deutsche Telekom, is another prominent NFV and SDN spokesperson at a top-tier carrier, one that hosted the last few SDN & OpenFlow World Congresses in Germany. DT is in the process of transforming its European network to all-IP so that it’s easier to virtualize services. So far, it’s moved to all-IP in Croatia, Montenegro, Slovakia, and Macedonia, and its roadmap calls for the project to be complete in the 13 European countries it serves by 2018. At the GEN15 conference in Dallas in November, Clauberg said, “By bringing in virtualization, we’re adding complexity. As a multi-country operation, this simplification [transforming to IP] allows us to deliver cross-country services.”

In June 2014 Prodip Sen, the executive who’d become a figurehead for NFV at Verizon, left that company and joined what's now Hewlett Packard Enterprise (HPE). In 2015, he settled into his role as CTO of NFV at HPE, where he's leading the company’s effort to create a complete NFV reference architecture known as OpenNFV. A similar NFV framework is brewing at OPNFV, the open source group that has Sen as its chairman.

The founders of Versa Networks, brothers Kumar Mehta and Apurva Mehta, seemed to be all over the place in the second half of 2015. They were previously star engineers at Juniper Networks, and their notoriety made Versa stand out among NFV startups. Versa decouples software from hardware for three primary use cases: virtual customer premises equipment (vCPE), software-defined WAN (SD-WAN), and virtualized branch security. It's attracted Verizon Ventures as an investor. And the company was prominent at the SDN World Congress in Germany.

Speaking of Juniper, Rami Rahim has only been CEO there for about a year, but during that time the company has made some moves in the NFV space. At its inaugural customer event, Nxtwork 2015, it unveiled its new Cloud CPE product with Contrail service orchestration and an on-premises device that can run multiple virtual network functions (VNFs), from Juniper and third parties, simultaneously. The company also announced it was separating its Junos operating system from its hardware, making the OS available for white-box products.

Chuck Robbins makes the list primarily for ending the 20-year reign of John Chambers at Cisco. Not content to operate in Chambers’s large shadow, Robbins took over as CEO with a redefined executive team, and in November, he announced Cisco was partnering with Ericsson — a move, supposedly 13 months in the making, that might reset the competitive landscape of all the big networking vendors, especially in light of the Nokia deal for Alcatel-Lucent.

And speaking of that deal, Basil Alwan, president of IP routing and transport at Alcatel-Lucent, has been with the company for 12 years and has helped make the company a formidable rival to Cisco and Juniper, according to SDxCentral analyst Scott Raynovich. When Nokia Networks announced some preliminary leadership roles for its upcoming purchase of Alcatel-Lucent, it said Alwan will be president of IP/optical networks, essentially keeping his same role and presumably having a big say in Nokia's future networking direction.