| 1997 | MCSE | Microsoft Certified Systems Engineer | Microsoft | 
  
    |  | MCP SI | Module Internet
      Specialist | Microsoft | 
  
    | 1998 | BNRS | Bay Networks Router
      Specialist | Bay Networks | 
  
    | 1999 | CCNA | Cisco Certified
      Network Associate | Cisco Systems | 
  
    |  | CCIE Routing & Switching | Cisco Certified
      Internetwork Expert (Routing & Switching) | Cisco Systems | 
  
    | 2000 | CCIE | ISP-Dial
      theoretische Prüfung | Cisco Systems | 
  
    |  | CCDA | Cisco Certified
      Design Associate | Cisco Systems | 
  
    |  | CCDP | Cisco Certified
      Design Professional | Cisco Systems | 
  
    |  | CCNP | Cisco Ceritified
      Network Professional | Cisco Systems | 
  
    |  | CCNP Security | Cisco Ceritified
      Network Professional specialisation
      Security | Cisco Systems | 
  
    |  | CCNP Voice | Cisco Ceritified
      Network Professional specialisation
      Voice | Cisco Systems | 
  
    |  | NNCDS | Nortel Networks
      Certified Design Specialist | Nortel Networks | 
  
    |  | NNCAS | Nortel Networks
      Certified Account Specialist | Nortel Networks | 
  
    |  | NNCSE | Nortel Networks
      Certified Support Expert | Nortel Networks | 
  
    | 2001 | CCIE | Rezertifizierung CCIE (bis 13.07.2003) | Cisco Systems | 
  
    | 2003 | CCIE Security | double Cisco Certified
      Internetwork Expert Security | Cisco Systems | 
  
    | 2004 - 2007 | Cisco | Cisco CQS Security, WLAN, UC | Cisco Systems | 
  
    | 2008 | CCIE Voice | triple Cisco Certified Internetwork Expert (Voice) | Cisco Systems | 
  
    | 2009 | planned | Cisco's new CCDE Certification | Cisco Systems | 
  
    |  |  |  |  |