By Topic

TCP with sender-side intelligence to handle dynamic, large, leaky pipes

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$31 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

4 Author(s)
Wang, R. ; Comput. Sci. Dept., Univ. of California, Los Angeles, CA, USA ; Yamada, K. ; Sanadidi, M.Y. ; Gerla, M.

Transmission control protocol Westwood (TCPW) has been shown to provide significant performance improvement over high-speed heterogeneous networks. The key idea of TCPW is to use eligible rate estimation (ERE) methods to intelligently set the congestion window (cwnd) and slow-start threshold (ssthresh) after a packet loss. ERE is defined as the efficient transmission rate eligible for a sender to achieve high utilization and be friendly to other TCP variants. This work presents TCP Westwood with agile probing (TCPW-A), a sender-side only enhancement of TCPW, that deals well with highly dynamic bandwidth, large propagation time/bandwidth, and random loss in the current and future heterogeneous Internet. TCPW-A achieves this goal by adding the following two mechanisms to TCPW. 1) When a connection initially begins or restarts after a timeout, instead of exponentially expanding cwnd to an arbitrary preset sthresh and then going into linear increase, TCPW-A uses agile probing, a mechanism that repeatedly resets ssthresh based on ERE and forces cwnd into an exponential climb each time. The result is fast convergence to a more appropriate ssthresh value. 2) In congestion avoidance, TCPW-A invokes agile probing upon detection of persistent extra bandwidth via a scheme we call persistent noncongestion detection (PNCD). While in congestion avoidance, agile probing is actually invoked under the following conditions: a) a large amount of bandwidth that suddenly becomes available due to change in network conditions; b) random loss during slow-start that causes the connection to prematurely exit the slow-start phase. Experimental results, both in ns-2 simulation and lab measurements using actual protocols implementation, show that TCPW-A can significantly improve link utilization over a wide range of bandwidth, propagation delay, and dynamic network loading.

Published in:

Selected Areas in Communications, IEEE Journal on  (Volume:23 ,  Issue: 2 )