Exhibit 21

Subsidiaries of the Registrant



|                                                             |  |                            
|------------------------------------------------------------ |  | ---------------------------
|                                                             |  | Organized under the laws of
|                                                             | 
|1328556 Ontario Inc.                                         |  | Ontario, Canada            
|AC Technologies, Inc.                                        |  | State of Delaware          
|Bay Networks do Brasil Ltda.                                 |  | Brazil                     
|Bay Networks Redes de Dados para Sistemas Informaticos, Lda. |  | Portugal                   
|Capital Telecommunications Funding Corporation               |  | Canada                     
|Clarify K.K.                                                 |  | Japan                      
|Clarify Limited                                              |  | United Kingdom             
|CTFC Canada Inc.                                             |  | Canada                     
|Diamondware, Ltd.                                            |  | State of Arizona           
|Frisken Investments Pty. Ltd.                                |  | New South Wales, Australia 
|Integrated Information Technology Corporation                |  | State of Illinois          
|Guangdong-Nortel Telecommunications Equipment Company Ltd.   |  | Peoples Republic of China 
|LG-Nortel Co. Ltd.                                           |  | Korea                      
|Matra Communications Business Systeme GmbH                   |  | Germany                    
|Matra Communication Cellular Terminals GmbH                  |  | Germany                    
|Nortel Australia Communication Systems Pty. Limited          |  | New South Wales, Australia 
|Nortel Communications Holdings (1997) Limited                |  | Israel                     
|Nortel Communications Inc.                                   |  | Ontario, Canada            
|Nortel de Mexico, S. de R.L. de C.V.                         |  | Mexico                     
|Nortel Government Solutions Incorporated                     |  | State of Delaware          
|Nortel GmbH                                                  |  | Germany                    
|Nortel Limited                                               |  | United Kingdom             
|Nortel Networks (Asia) Limited                               |  | Hong Kong                  
|Nortel Networks (Austria) GmbH                               |  | Austria                    
|Nortel Networks (Bulgaria) EOOD                              |  | Bulgaria                   
|Nortel Networks (CALA) Inc.                                  |  | State of Florida           
|Nortel Networks (China) Limited                              |  | Peoples Republic of China 
|Nortel Networks (India) Private Limited                      |  | New Delhi, India           
|Nortel Networks (Ireland) Limited                            |  | Ireland                    
|Nortel Networks (Northern Ireland) Limited                   |  | Northern Ireland           
|Nortel Networks (Photonics) Pty Ltd                          |  | New South Wales, Australia 
|Nortel Networks (Shannon) Limited                            |  | Ireland                    
|Nortel Networks (Thailand) Ltd.                              |  | Thailand                   
|Nortel Networks AB                                           |  | Sweden                     
|Nortel Networks AG                                           |  | Switzerland                
|Nortel Networks AS                                           |  | Norway                     
|Nortel Networks Australia Pty Limited                        |  | Australia                  
|Nortel Networks BV                                           |  | The Netherlands            
|Nortel Networks Cable Solutions Inc.                         |  | State of Delaware          
|Nortel Networks Capital Corporation                          |  | State of Delaware          
|Nortel Networks Chile S.A.                                   |  | Chile                      
|Nortel Networks Communications Engineering Ltd.              |  | Peoples Republic of China 
|Nortel Networks Communications (Israel) Limited              |  | Israel                     
|Nortel Networks de Argentina S.A.                            |  | Argentina                  
|Nortel Networks de Bolivia S.A.                              |  | Republic of Bolivia        
|Nortel Networks de Colombia S.A.                             |  | Colombia                   



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|                                                             |  |                            
|------------------------------------------------------------ |  | ---------------------------
|                                                             |  | Organized under the laws of
|                                                             | 
|Nortel Networks de Guatemala Ltda.                           |  | Guatemala                  
|Nortel Networks de Mexico S.A. de C.V.                       |  | Mexico                     
|Nortel Networks de Panama S.A.                               |  | Republic of Panama         
|Nortel Networks de Venezuela C.A.                            |  | Venezuela                  
|Nortel Networks del Ecuador S.A.                             |  | Republic of Ecuador        
|Nortel Networks del Paraguay S.A.                            |  | Paraguay                   
|Nortel Networks del Uruguay S.A.                             |  | Uruguay                    
|Nortel Networks Eastern Mediterranean Ltd.                   |  | Israel                     
|Nortel Networks Electronics Corporation                      |  | Canada                     
|Nortel Networks Employee Benefit Trustee Company Limited     |  | United Kingdom             
|Nortel Networks Engineering Service Kft.                     |  | Hungary                    
|Nortel Networks Europe Sales Limited                         |  | Ireland                    
|Nortel Networks Financial Services Limited Liability Company |  | Hungary                    
|Nortel Networks France SAS                                   |  | France                     
|Nortel Networks Global Corporation                           |  | Canada                     
|Nortel Networks Hispania, S.A.                               |  | Spain                      
|Nortel Networks HPOCS Inc.                                   |  | State of Delaware          
|Nortel Networks Inc.                                         |  | State of Delaware          
|Nortel Networks India International Inc.                     |  | State of Delaware          
|Nortel Networks International Corporation                    |  | Canada                     
|Nortel Networks International Finance & Holding B.V.         |  | The Netherlands            
|Nortel Networks International Inc.                           |  | State of Delaware          
|Nortel Networks Israel (Sales and Marketing) Limited         |  | Israel                     
|Nortel Networks Japan                                        |  | Japan                      
|Nortel Networks Korea Limited                                |  | Korea                      
|Nortel Networks Malaysia Sdn. Bhd.                           |  | Malaysia                   
|Nortel Networks Malta Limited                                |  | Malta                      
|Nortel Networks Mauritius Ltd.                               |  | Mauritius                  
|Nortel Networks NV                                           |  | Belgium                    
|Nortel Networks Netas Telekomunikasyon A.S.                  |  | Turkey                     
|Nortel Networks New Zealand Limited                          |  | New Zealand                
|Nortel Networks O.O.O.                                       |  | Russia                     
|Nortel Networks Optical Components Inc.                      |  | State of Delaware          
|Nortel Networks Optical Components Limited                   |  | United Kingdom             
|Nortel Networks OY                                           |  | Finland                    
|Nortel Networks Peru S.A.C.                                  |  | Peru                       
|Nortel Networks Polska Sp. z o.o.                            |  | Poland                     
|Nortel Networks Portugal, S.A.                               |  | Portugal                   
|Nortel Networks Properties Limited                           |  | United Kingdom             
|Nortel Networks Romania Srl                                  |  | Romania                    
|Nortel Networks S.A.                                         |  | France                     
|Nortel Networks S.p.A.                                       |  | Italy                      
|Nortel Networks S.R.O.                                       |  | Czech Republic             
|Nortel Networks Singapore Pte Ltd.                           |  | Singapore                  
|Nortel Networks Slovensko, s.r.o.                            |  | Slovak Republic            
|Nortel Networks South Africa (Proprietary) Limited           |  | South Africa               
|Nortel Networks Southeast Asia Pte Ltd                       |  | Singapore                  
|Nortel Networks Technology (Thailand) Ltd.                   |  | Thailand                   



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|                                                                  |  |                            
|----------------------------------------------------------------- |  | ---------------------------
|                                                                  |  | Organized under the laws of
|                                                                  | 
|Nortel Networks Technology K.K.                                   |  | Japan                      
|Nortel Networks Technology Corporation                            |  | Nova Scotia, Canada        
|Nortel Networks Technology Ltd.                                   |  | Cayman Islands             
|Nortel Networks Telecommunications Equipment (Shanghai) Co., Ltd. |  | Peoples Republic of China 
|Nortel Networks Telecomunicacoes do Brasil Ltda.                  |  | Brazil                     
|Nortel Networks UK Limited                                        |  | United Kingdom             
|Nortel Technology Excellence Centre Private Limited               |  | Bangalore, India           
|Nortel Telecom International Limited                              |  | Nigeria                    
|Nortel Trinidad and Tobago Limited                                |  | Trinidad and Tobago        
|Nortel Ukraine Ltd.                                               |  | Ukraine                    
|Nortel Ventures LLC                                               |  | State of Delaware          
|Nortel Vietnam Limited                                            |  | Vietnam                    
|Northern Telecom Canada Limited                                   |  | Canada                     
|Northern Telecom France SA                                        |  | France                     
|Northern Telecom International Inc.                               |  | State of Delaware          
|Northern Telecom Maroc SA                                         |  | Morocco                    
|Northern Telecom PCN Limited                                      |  | United Kingdom             
|Nor.Web DPL Limited                                               |  | United Kingdom             
|Novera Optics, Inc.                                               |  | State of Delaware          
|Novera Optics Korea Inc.                                          |  | Korea                      
|Penril Datacomm Limited                                           |  | United Kingdom             
|Periphonics Limited                                               |  | United Kingdom             
|Promatory Communications (UK) Limited                             |  | United Kingdom             
|PT Nortel Networks Indonesia                                      |  | Jakarta, Indonesia         
|Qtera Corporation                                                 |  | State of Delaware          
|R. Betts Investments Pty. Ltd.                                    |  | New South Wales, Australia 
|Regional Telecommunications Funding Corporation                   |  | Canada                     
|Shenyang Nortel Telecommunications Co., Ltd.                      |  | Peoples Republic of China 
|Star 21 Networks GmbH                                             |  | Germany                    
|Star 21 Facility Management GmbH & Co. KG                         |  | Germany                    
|Star 21 Facility Management Verwaltung GmbH                       |  | Germany                    
|Star 21 NETWORKS Deutschland GmbH                                 |  | Germany                    
|Star 21 NETWORKS (Schweiz) AG                                     |  | Switzerland                
|Star 21 Operations GmbH                                           |  | Germany                    
|Telephone Switching International Limited                         |  | United Kingdom             
|The Nortel Foundation                                             |  | State of Virginia          
|TSFC Canada Inc.                                                  |  | Canada                     
|X-CEL Communications Limited                                      |  | United Kingdom