AT&T Inc., Goldman Sachs Group Inc., Facebook Inc. and other companies are embracing software to run their networks -- a shift that poses a challenge to hardware makers led by Cisco Systems Inc. (CSCO)
Instead of buying expensive new routers and switches that move Internet traffic, they’re opting for networks that rely more on software and inexpensive hardware. The new technology is called software-defined networking, or SDN, and lets users add speed and features while cutting costs.