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Dr.Jun Takei #07 02/27/2007

More TCP Problems with Wireless

• Bursts of errors may occur due to low signal strength or longer period of noise
  
  
  • More than one packet lost in TCP
    
    
  • More likely to be detected as a timeout ? enter slow start!
    
    
• Delay is often very high
  
  
  • Round-trip time can be very long and variable
    
    
  • TCP�fs timeout mechanisms may not work well
    
    
  • Problem exacerbated by link-level retransmission
    
    
• Links may be asymmetric
  
  
  • Delayed ACKs in the slow direction can limit throughput in the fast direction