Inferring TCP Behavior Notes

Abstract

• stability and fairness of the internet relies on the use of congestion control mechanisms
  • refers to the congestion collapse in the 80s
  • bandwidth - describes the maximum data transfer amount over a certain time
• [TBIT can] detect bugs and non-compliance in TCP implementations deployed in public web servers

Introduction

• Understanding TCP behavior can be important for Internet-related research, ISPs, OS Vendors and application developers.
• [web servers were chosen to test TCP behavior because] web servers will respond to a request for information without requiring any special privileges
• TBIT shows that newer TCP variants such as NewReno and SACK are widely deployed in the Internet
• TCP initial window used at a web server can not necessarily be inferred simply by knowing the operating system used at that server
• useful not only in simulations and modeling, but also in standards-body decisions to advance documents specifying larger values for initial windows
• ability to publically identify end hosts not conforming to end-to-end congestion control can help significantly in reinforcing the use of end-to-end congestion control in the Internet
• TBIT...identifies these failure modes and the extent of their deployment in the Internet, to identify the responsible vendors, and to track the progress (or lack of progress)
• TCP behavior determined by equipment on the path to the server
• [tests of ECN are] testing for the presence of firewalls and load balancers that block access to servers from hosts attempting to negotiate ECN
• interested in understanding the congestion control behavior in the Internet and not just the congestion control of the web server boxes

KEY

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