TCP-DCR: MAKING TCP ROBUST TO NON-CONGESTION LOSSES Sumitha Bhandarkar and A. L. Narasimha Reddy

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TCP-DCR MAKING TCP ROBUST TO NON-CONGESTION
LOSSESSumitha Bhandarkar and A. L. Narasimha
Reddy sumitha,reddy_at_ee.tamu.edu
Texas AM University
General Problem
Results With No Non-Congestion Losses
Application 2 Wireless Channel Errors
Loss of TCP Throughput for Non-congestion Events

• Rely on local recovery through link level
  retransmission.
• Delay of ? 1 RTT (gt wireless link delay)
  sufficient for link level recovery
• Delay of ? 1 RTT (lt TCP RTO) avoids
  retransmission timeouts
• TCP-DCR Behavior for Wireless Networks

Proposed Solution(TCP-DCR)

• Delay the congestion response for a short
  interval of time ?.
• Allows underlying mechanisms to handle
  non-congestion events.
• At the end of ? , treat unrecovered loss as a
  normal congestion event.
• Retransmission Timer (RTO) limits delay to about
  1 RTT.
• Steady state analysis shows throughput is
  TCP-Friendly.

Application 1 Packet reordering

• Packet reordering in Multipath routing, Parallel
  routers ? TCP problems
• TCP-DCR tolerates reordering delay upto ?.
• Delay of ? 1 RTT (lt TCP RTO) avoids
  retransmission timeouts
• TCP-DCR Behavior for Packet Reordering

Sample Result
Sample Result