Ericsson AB is partnering with Cisco Systems Inc. to develop telecommunications networks, the latest combination in the industry as equipment makers seek to expand their offerings to handle soaring Internet traffic. Stockholm-based Ericsson, the biggest maker of wireless networks, and San Jose, California-based Cisco, the largest maker of Internet-network gear such as routers and switches, said Monday they will cooperate in development and delivery of systems to telecommunications carriers and other customers.