Journal of KIISE:Computing Practices and Letters (한국정보과학회논문지:컴퓨팅의 실제 및 레터)

Korean Institute of Information Scientists and Engineers (한국정보과학회)
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An Enhanced TCP Congestion Control using Link-Error Rates at Wireless Edges

무선 에지의 링크 오류율을 이용한 개선된 TCP 혼잡제어

  • 오준석 (중앙대학교 컴퓨터공학부) ;
  • 박탄세 (중앙대학교 컴퓨터공학부) ;
  • 박창윤 (중앙대학교 컴퓨터공학부) ;
  • 정충일 (여주대학 인터넷정보처리학과)
  • Received : 2009.12.24
  • Accepted : 2010.03.29
  • Published : 2010.07.15
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Abstract

Assuming that a wireless link is mostly used at the network edge and the wireless NIC driver keeps monitoring the error rate of its link, this paper proposes an enhanced TCP congestion control, TCP-L (TCP Link-Aware). TCP-L predicts true congestion losses occurred inside the wired link area by utilizing the wireless link error rate. As a result, it mitigates performance degradation caused from TCP congestion control actions when segments losses occur in a wireless link. Experimental results show that TCP-L provides better performance and fairness in lossy wireless links than existing TCP congestion control schemes. Our approach utilizing the characteristic of the link at TCP could be well adapted to new wireless environments such as Cognitive Radio and ACK-less IEEE 802.11, where a frame may be delivered with a very long delay or lost in the link.

본 연구에서는 대부분의 무선 링크는 네트워크 에지에서 사용되고, NIC 드라이버가 무선 링크 오류율을 관찰하고 있다는 가정 하에, 기존 TCP의 혼잡제어를 수정한 TCP-L(TCP Link Aware)을 제안한다. TCP-L은 무선 링크 오류율을 이용해 유선 링크의 혼잡 손실률을 예측하여 무선 링크에서 세그먼트 손실이 발생했을 경우에 나타나는 성능 저하를 회피할 수 있다. 또한 실험을 통해 무선 링크 오류율이 높은 환경에서 다른 무선 TCP 보다 높은 처리율을 보이면서도 다른 유선 TCP 소스와의 형평성을 유지하는 것을 검증하였다. 본 연구의 접근 방법은 세그먼트 손실이 많거나 전송 지연이 산발적으로 발생하는 새로운 무선 환경, 즉 802.11 ACK-less와 인지 라디오(Cognitive Radio)와 같은 무선 링크에 효과적으로 적용될 수 있을 것으로 예상된다.

Keywords

Acknowledgement

Supported by : 중앙대학교

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