AT&T added Brocade, Ciena and Cisco to its list of Domain 2.0 partners on Wednesday, taking the total number of vendor partners it has chosen for its cloud program, which leans heavily on SDN and NFV, to 10.

The operator, which first unveiled its Domain 2.0 plans (also known as the User-Defined Network Cloud program) in September 2013, says the plan for its next-generation network "places customers at the center of the network with a modern, cloud-based architecture, a global first at this scale." (See AT&T Puts SDN/NFV in Driver's Seat.)

Importantly, AT&T Inc. (NYSE: T) continues to link the extension of its Domain 2.0 activities to an expected reduction in capital expenditures in the coming years. The operator recently announced that it expects to reduce its annual capex spend to $18 billion in 2015 compared with about $21 billion this year: In today's announcement it reiterated that it expects "its next-generation network to reflect a downward bias toward capital spending. This will come from relying less on specialized hardware and deploying more open source and reusable software." (See AT&T's Mexican Capex Dance.)

That's a massive signal to the rest of the operator community that AT&T is committed to the use of open source software in its future network and that it expects the evolution to more programmable and virtualized networking to result in lower capital expenditures.

While one of the "promises" of SDN and NFV has always been that it would result in lower capex for network operators, that direct financial link has been called into question during the past year or so. Yet AT&T, a very influential telco, is saying there is a correlation between the introduction of technologies that do not require a proprietary hardware platform and lower outlays.

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AT&T's share price is down by 0.4% Wednesday to $32.76, most likely due to the ongoing concerns about mobile service margins across all US wireless operators. (See US Carriers Spanked on Big Red's Q4 Margin Squeeze.)

A year ago this month, research firm MKM Partners suggested Ciena would be one of the winners in AT&T's program, and that Cisco could be left out. (See MKM: Cisco Biggest Loser in AT&T SDN Plans.)

Including the companies announced today, the 10 vendors currently involved in the Domain 2.0 program are (in alphabetical order):

For more on AT&T's Domain 2.0 program see:

— Ray Le Maistre, , Editor-in-Chief, Light Reading