Cisco Systems is to create 115 jobs at its plant in Oranmore in Co Galway.
The company currently employs about 180 people in Oranmore Business Park and is expected to start recruiting shortly.
It also has a sales and capital operation in Dublin.
Cisco, which is the world's largest supplier of networking products, is to invest €26m at its Galway research and development facility over two years.
The investment is being supported by IDA Ireland.
The new projects see Cisco's Galway operations move into new business areas in communication and collaboration software technology.
''70% of the world's internet traffic is routed through Cisco equipment and the company's investment in R&D activities in Galway will build considerable new capabilities in the Galway R&D team,'' IDA Ireland's chief executive Barry O'Leary said.
He said that the new research areas represent major growth opportunities in the area of collaboration software and are strategically significant for Cisco.
Barry O'Sullivan, senior vice president for Cisco's global collaboration business, said that access to diverse top-class engineering talent and support from IDA Ireland have helped build a successful, innovative and global development capability over the last five years.
''The projects announced today are in line with Cisco's strategic product and market priorities and will further increase the scale of the Irish operation in terms of both engineering capability and diversified technologies,'' he added.