Transcript User-Perceived Performance Measurement on the Internet

User-Perceived Performance
Measurement on the Internet
Bill Tice
Thomas Hildebrandt
CS 6255
November 6, 2003
Introduction
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The Internet is different from LANs
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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
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Why user-perceived performance
measurement is important and also difficult
Existing solutions to the global network
measurement problem
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NIMI
E2E piPEs
Client-side proxies and other solutions
Performance Measurement on the
Internet
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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
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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
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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
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DNS queries
HTTP requests
Performance Measurement
Architectures
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There have been projects to create
measurement architectures either by
deployment at nodes within domains or at
the users
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NIMI
E2E pIPEs
AMP, Medusa Proxy, Liston Proxy, Network
Weather Service …
NIMI
(National Internet Measurement Infrastructure)
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Software system for building network measurement
infrastructures
Diversely administered
Facilitate many kinds of measurements
Extensible and Modular
NIMI Architecture
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Measurement servers (probes)
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2 daemons: nimid and scheduled
Measurement Modules
NIMI Architecture
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Configuration Point of Contact (CPOC)
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Configuration and Control Servers
Several per domain
Delegation of configuration access
NIMI Architecture
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Measurement Client (MC)
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Only ‘user’ point of contact with NIMI system
Measurement requests
NIMI Architecture
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Data Analysis Client (DAC)
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Data Collection
Post-Processing
Run at central location or at MC
NIMI Measurement Modules
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NIMI has no knowledge of measurements
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Plug-ins
Wrapped for a standard API
Current Modules
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traceroute, treno, zing, mflect, traffic, ftp
NIMI Measurements
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Request Received from MC
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Access Control List
scheduled creates pending measurement
Results sent to DAC by nimid
All communications encrypted
NIMI Deployment
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35 hosts (as of 2001)
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Research laboratories and Universities
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Georgia Tech
Dead?
NIMI Difficulties
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Laboratory Conditions
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High bandwidth
Dedicated Resources
Not representative of Internet as a whole
NIMI Difficulties
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Meaningful data for User Perceived
measurements
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Not widely distributed
NIMI Difficulties
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Hosts administration difficulties
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Tools requiring privileged access
Updates
NIMI Difficulties
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Difficult to distribute
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What’s in it for me?
Not attractive to average user
E2E piPEs
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End-to-end Performance Improvement
Performance Environment System
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A framework to indicate performance capabilities
and locate performance problems along the path
between two computers connected by the Abilene
network
E2E piPEs Architecture
E2E piPEs Architecture
OWAMP
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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
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E2E piPEs Status
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“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
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Liston Proxy
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Between browser and the Web
Handles DNS resolution and content requests
Logs information of interest
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DNS responsiveness
Response time
Proxy-Based Tools
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Medusa Proxy
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Cool name
Monitors performance
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DNS
Akamai edge servers vs. origin servers
Proxy-Based Disadvantages
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Privacy issues
Overhead
Limited Scope
Distributed Tools
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AMP Network
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Distributed physical nodes
High Performance Computing (HPC)
Network measurement, not user-perceived
Distributed Tools Disadvantages
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Wide Distribution
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Need large amounts of diverse data
How to do it
Updates
Security
Applications
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Network Weather Service
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Predicting network performance for
applications
Can be run by user to predict their
performance
Applications
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Lots
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Zing
Ping
IPerf
Traceroute
NM Applications Disadvantages
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Limited Scope
Generally Stateless
User-Perceived Performance
Measurement: Why?
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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?
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The infrastructure
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NIMI-like plug-in measurement modules
Standardized communication between
components
User-Perceived Measurement: How?
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Distribution
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Have to make it something users want to run
User-Perceived Measurement: How?
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Processing
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Centralized data collection and post-processing
References
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[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