AT&T has added Cisco, Brocade, and Ciena as official suppliers for its Domain 2.0 future networking initiative, the company announced Wednesday.

The three networking heavyweights join seven others announced so far as vendors for Domain 2.0, a program meant to expand AT&T's vendor base in order to build out software-defined infrastructure. That infrastructure vision, announced in February, officially goes by the awkward moniker “User-Defined Network Cloud.”

The announcement is possibly Brocade's first major deal with AT&T. A Brocade spokesman declined to comment on the company's previous business with AT&T or the nature of the new Domain 2.0 partnership.

AT&T is already one of Ciena's two largest customers, and Cisco has been the carrier's primary Ethernet switch provider. That makes the Domain 2.0 partnership welcome news for both companies, as incumbent vendors battle for a share of the carrier's shrinking capital expenditures.

AT&T last month projected that its capital spending would drop to $18 billion next year, a 15 percent decline from 2014.

The new Domain 2.0 partnerships don't change that projection, the company said in a statement, adding that it expects future networking deployments to further reduce capital expenditures over the next five years by "relying less on specialized hardware and deploying more open source and reusable software."

Seen as a way to bring startups into AT&T's supplier ranks, the Domain 2.0 partner list has grown heavy with traditional players as incumbents race into SDN and NFV. The list of announced partners now includes Affirmed Networks, Alcatel-Lucent, Amdocs, Ericsson, Fujitsu, Juniper, and Metaswitch — and Tail-f, a startup that was included in the program early on and was subsequently acquired by Cisco.