Nokia Networks is the primary division of the company and is focused on radio access and core which provides the infrastructure for all mobile networks globally. The company was a key participant in the development of the standards and technology for 2/3/4 and now 5G.
It was formerly known as NSN since it was a joint venture between Siemens and Nokia but is now wholly owned by Nokia. After Nokia bought back the Siemens holding the company reverted to simply Nokia Networks.
Previously the company produced TDM systems for transmission using PDH and SDH technology and there remains a footprint of this equipment in use today, they subsequently sold this range to Marconi where it became the foundation for SMA and OMS. Nokia also acquired Alcatel Lucent which represents a significant portion of the optical and IP market for telecom equipment today.