user-perceived performance measurement on the internet bill tice thomas hildebrandt cs 6255 november...
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User-Perceived Performance Measurement on the Internet
Bill Tice
Thomas Hildebrandt
CS 6255
November 6, 2003
Introduction
The Internet is different from LANs– Diversely administered– Users are relatively distant from the network
administrators– IP is the only service provided by the network– SNMP or something like it? No…
Overview
Why user-perceived performance measurement is important and also difficult
Existing solutions to the global network measurement problem– NIMI– E2E piPEs– Client-side proxies and other solutions
Performance Measurement on the Internet
IP was designed around the end-to-end argument: certain functions are not required at low levels of a system [1]
As a result, we have a “dumb network” with no built-in performance measurement architecture
The tools we can count on are limited
Performance Measurement on the Internet: Example Tools
Packet Internet Groper (ping) – Useful to test connectivity and RTT between hosts
Traceroute – Provides an approximation of the network topology in the forward direction
Iperf – Measures TCP and UDP performance, including bandwidth, delay jitter and packet loss
Performance Measurement on the Internet
Ping and traceroute rely on ICMP, which is increasingly being blocked by network administrators
Active measurement based on the use of common network services is more robust and perhaps more realistic– DNS queries– HTTP requests
Performance Measurement Architectures
There have been projects to create measurement architectures either by deployment at nodes within domains or at the users– NIMI– E2E pIPEs– AMP, Medusa Proxy, Liston Proxy, Network
Weather Service …
NIMI(National Internet Measurement Infrastructure)
Software system for building network measurement infrastructures
Diversely administered Facilitate many kinds of measurements Extensible and Modular
NIMI Architecture
Configuration Point of Contact (CPOC)– Configuration and Control Servers– Several per domain– Delegation of configuration access
NIMI Architecture
Measurement Client (MC)– Only ‘user’ point of contact with NIMI system– Measurement requests
NIMI Architecture
Data Analysis Client (DAC)– Data Collection– Post-Processing– Run at central location or at MC
NIMI Measurement Modules
NIMI has no knowledge of measurements– Plug-ins
Wrapped for a standard API Current Modules
– traceroute, treno, zing, mflect, traffic, ftp
NIMI Measurements
Request Received from MC– Access Control List
scheduled creates pending measurement Results sent to DAC by nimid All communications encrypted
NIMI Difficulties
Laboratory Conditions– High bandwidth– Dedicated Resources– Not representative of Internet as a whole
E2E piPEs
End-to-end Performance Improvement Performance Environment System– A framework to indicate performance capabilities
and locate performance problems along the path between two computers connected by the Abilene network
OWAMP
One-Way Active Measurement Protocol: An Internet2 project
A UDP-based protocol to precisely measure network characteristics:
– Loss– Delay– Jitter
http://owamp.internet2.edu/ - Under construction
E2E piPEs Status
“The initial deployment, which includes the Abilene backbone network and two campuses only, is scheduled for Fall 2003.”
“piPEfitters” are still developing the system – one suggestion is to place PMPs at the end hosts.
Other Tools: Proxy-Based
Liston Proxy– Between browser and the Web– Handles DNS resolution and content requests– Logs information of interest
DNS responsiveness Response time
Proxy-Based Tools
Medusa Proxy– Cool name– Monitors performance
DNS Akamai edge servers vs. origin servers
Distributed Tools
AMP Network– Distributed physical nodes– High Performance Computing (HPC)
Network measurement, not user-perceived
Distributed Tools Disadvantages
Wide Distribution– Need large amounts of diverse data– How to do it
Updates Security
Applications
Network Weather Service– Predicting network performance for
applications– Can be run by user to predict their
performance
User-Perceived Performance Measurement: Why?
Because the Internet was designed following the end-to-end principle, end-to-end performance is ultimately the most meaningful to measure
It is difficult to deploy a measurement architecture in the Internet backbone
Network users see end-to-end performance directly and could be effectively used as monitor points
User-Perceived Measurement: How?
The infrastructure– NIMI-like plug-in measurement modules– Standardized communication between
components
References
[1] J.H. Saltzer, D.P. Reed, and D.D. Clark. “End to End Arguments in System Design.” http://web.mit.edu/Saltzer/www/publications/endtoend/endtoend.txt
[2] Vern Paxson, Andrew Adams, and Matt Mathis. “Experiences with NIMI.” In Proceedings of Passive and Active Measurement, 2000. http://citeseer.nj.nec.com/paxson00experiences.html
[3] Internet2. E2E piPEs. http://e2epi.internet2.edu/E2EpiPEs/e2epipe_index.html
[4] Richard Liston and Ellen Zegura. “Using a Proxy to Measure Client-Side Web Performance.” Proceedings of the 6th International Web Caching and Content Distribution Workshop, Boston, MA, June 1999. http://www.cc.gatech.edu/~liston/pubs/proxy_wcw01.ps.gz
Network Weather Service http://www.npaci.edu/envision/v15.2/nws.html