WindowBased Error Recovery and Flow Control with a Slow Acknowledgement Channel A Study of.pdfVIP

Window-based error recovery and flow control with a slow acknowledgement channel: a study of TCP/IP performance T. V. Lakshmany U. Madhow Bernhard Sutery y Bell Labs University of Illinois Lucent Technologies Electrical and Computer Engineering Department 101 Crawfords Corner Road Urbana, Illinois 61801. Holmdel, NJ 07733 USA USA Abstract access traffic is bidirectional and hence causing the slow up- With the envisaged growth in Internet access services stream link from the subscriber to the network to be shared over networks with asymmetric links such as Asymmetric by both data packets (where the destination is upstream) Digital Subscriber Line (ADSL) and Hybrid Fiber Coax and ACK packets (where the destination is downstream). (HFC), it becomes crucial to evaluate the performance of Moreover, asymmetric traffic can cause congestion in the window-based protocols over systems in which the reverse acknowledgement path even when there is no bandwidth link is considerably slower than the forward link. Even if asymmetry. the actual bandwidth asymmetry is moderate, high effec- Since TCP uses the arrival rate of ACKs in the reverse tive asymmetries can result because of bidirectional traffic. channel to control packet flow in the forward direction, Our objective is to determine, whether TCP/IP performs congestion in the reverse path may lead to poor utiliza- reasonably in a setting in which the reverse link is the pri- tion of the forward path. The objective of this paper is to mary bottleneck. Our main results are: character