TCP Vegas Congestion Control Algorithm

1 / 6

TCP Vegas Congestion Control Algorithm - PowerPoint PPT Presentation

TCP Vegas Congestion Control Algorithm. Mridul Sharma CS 590f Project Presentation. Contents. Motivation TCP Vegas Congestion Control Algorithm Slow Start Congestion Avoidance Fast Retransmit The Problem Simulations Conclusions. Motivation.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

PowerPoint Slideshow about 'TCP Vegas Congestion Control Algorithm' - tucker

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

TCP Vegas Congestion Control Algorithm

Mridul Sharma

CS 590f Project Presentation

Contents
• Motivation
• TCP Vegas Congestion Control Algorithm
• Slow Start
• Congestion Avoidance
• Fast Retransmit
• The Problem
• Simulations
• Conclusions
Motivation
• Past researches have shown that TCP Vegas is able to achieve higher throughput with lesser retransmissions than TCP Reno, which is widely used in the current internet.
• It is required to consider the migration path for TCP Vegas to be deployed in the operating network.
Congestion Avoidance
• Expected = CWND/BaseRTT
• Actual = CWND/RTT
• Diff = (Expected – Actual) BaseRTT
• CWND = CWND + 1 if Diff < 
• CWND = CWND – 1 if Diff > 
• No change other wise

Slow Start Congestion Avoidance

If Diff > 

The Problem

The TCP Reno Congestion avoidance scheme is aggressive in the sense that it leaves little room in the buffer for other connections, while TCP Vegas is conservative and tries to occupy little buffer space.

When a TCP Vegas connection shares a link with TCP Reno connection, the TCP Reno connection uses most of the buffer space and the TCP Vegas connection backs off, interpreting this as a sign of network congestion.

Conclusions

It is necessary to achieve fairness between Vegas and Reno connections for deployment of TCP Vegas into the operating network.

There are two approaches

Modify the TCP Vegas congestion Control Algorithm

Modify the router packet dropping schemes like RED to detect misbehaving flows (Reno in this case) and punish them more severely.