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by Kenjiro Cho #07 11/28/2002

clock uncertainty

• clock uncertainty
  
  
  • synchronization
    
    
    • difference of 2 clocks
      
      
  • accuracy
    
    
    • a given clock agrees with UTC
      
      
  • resolution
    
    
    • precision of a given clock
      
      
  • skew
    
    
    • change of accuracy or of synchronization with time
      
      
• time precision
  
  
  • local clock skew/drift: 0.1-1sec/day
    
    
  • NTP: synchronizes clock within 10-100ms
    
    
  • tcpdump timestamp: 100usec-100msec (usually < 1msec)