Nortel Networks Corporation (Nortel) — formerly Northern Telecom Limited and, before that, Northern Electric — was a Canadian telecommunications and data-networking equipment manufacturer founded in 1895 in Montreal and later headquartered in Mississauga/Brampton, Ontario. It was publicly traded (NYSE/TSX: NT) and, at its peak around 2000, employed roughly 94,000 people and accounted for over a third of the value of the Toronto Stock Exchange 300 index. By its final full year (2008) revenue had fallen to about US$10.4 billion with a net loss of US$5.8 billion. Nortel filed for creditor protection under Canada's CCAA and Chapter 11 in the U.S. on January 14, 2009, and was liquidated rather than reorganized. The equity was delisted and is worthless; there is no current parent or operating owner.
Nortel sold digital central-office switches (the DMS-100 line), carrier wireless infrastructure across CDMA, GSM and LTE, optical and Metro Ethernet transport gear, enterprise PBX/VoIP and data-networking systems, plus global services. Its business units were sold off piecemeal: the wireless business to Ericsson (and Nokia Siemens Networks for parts), the enterprise unit to Avaya, and other lines to buyers including Ciena and Genband. Asset sales raised roughly US$7–8 billion in total.
Patent-litigation posture: Nortel appears only as a defendant in the tracked data (0 plaintiff cases, 1 defendant case) — consistent with an operating company being targeted, not a patent assertion entity. The single tracked suit, Fenner Investments, Ltd. v. Juniper Networks, Inc. et al., was filed January 6, 2005 in the U.S. District Court for the Eastern District of Texas, Tyler Division, a historically plaintiff-friendly patent venue.
Case context: Fenner Investments, a Richardson, Texas limited partnership holding patents of inventor Peter R. Fenner, asserted packet-source-filtering and switching patents (U.S. 5,561,706 and 6,819,670) against a group of networking and telecom vendors including Juniper, Cisco, Nokia, Ericsson, Lucent/UTStarcom and Nortel. Nortel was dismissed by stipulation in August 2006. Separately, Nortel's ~6,000-patent portfolio was auctioned in 2011 and bought for US$4.5 billion by the Rockstar Bidco consortium (Apple, Microsoft, RIM, EMC, Ericsson, Sony); those patents were later asserted by Rockstar and largely resold to RPX in 2014.