Developing Web100 Based Network Configuration & Performance Measurement Tools Web-100 Workshop Aug 1, 2002 by Rich Carlson Argonne National Laboratory.

Developing Web100 Based Network Configuration &

Performance Measurement Tools

Web-100 Workshop

Aug 1, 2002

by

Rich Carlson

Argonne National Laboratory

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Motivation for work

• Develop “single shot” diagnostic tool that doesn’t us historical data

• Measure performance to users desktop

• Combine numerous Web100 variables to analyze connection

• Develop network signatures for ‘typical’ network problems

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ANL’s Web100 Based Approach

• Single test to gather end-to-end data

• Gather data from multiple variables

• Compare measured performance to analytical values

• Translate network values into plain text messages

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Different HW same Network port

• 10 Mbps NIC– Jan 25 09:30:45 146.137.160.253 6826 6781 Kbs

5840 16382 B 0 20 ms 25 3 2

• 100 Mbps NIC– Jan 25 10:05:57 146.137.160.252 84557 86514 Kbs

5792 63712 B 0 10 ms 0 0 0

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Sample results

100 Mbps FD

Ave Rtt %loss5.41 0.00

1.38 0.78

6.16 0.00

14.82 0.0010 Mbps

72.80 0.01

8.84 0.75

Speed94.09

22.50

82.66

33.61

6.99

7.15

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Sample results

100 Mbps FD

Ave Rtt %loss loss/sec5.41 0.00 0.03

1.38 0.78 15.11

6.16 0.00 0.03

14.82 0.00 0.1010 Mbps

72.80 0.01 0.03

8.84 0.75 4.65

Speed94.09 Good

22.50 Bad NIC

82.66 Bad reverse

33.61 Congestion

6.99 Good

7.15 Bad NIC

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ANL developed tools

• Web based tool– based on ORNL tool– modified analysis messages

• Command line based tool– modified version of NLANR’s Iperf ver 1.2– supports 2 new options

• -e (-ee) print Web100 derived details

• -R reverse direction of data flow

– modified analysis messages

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ANL developed tools

• Geared toward campus area network

• End-user based view of network

• Provides some ‘hard evidence’ to users and network administrators to reduce finger pointing

• Can be used to identify performance bottlenecks

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Web Based Performance tool

• Operates on Any client with a Java enabled Web browser

• What it can do– Positively state if Sender, Receiver, or Network

is operating properly– Provide accurate application tuning info– Suggest changes to improve performance

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Web base Performance tool

• What it can’t do– Tell you how a 3rd party is performing– Tell you where in the network the problem is– Tell you how other clients will perform

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Network Signatures

• Duplex Mismatch Detection– Connection is Congestion limited

• CWNDtime > 30%

– Have experienced packet loss• MaxSsthesh > 0

– Retransmitting packets• PktsRetrans/sec > 2

– Throughput is less than expected• estimate > 2

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Network Signatures

• Full/Half Duplex Detection– Connection is Receiver buffer limited

• RWINtime > 95%

– Connection transitions between Receiver limited and Sender limited

• RwinTrans/sec > 30

• SendTrans/sec > 30

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Current Deployment

• 3 servers at ANL– Miranda Externally visible– Ophelia, Cordelia ANL Internal only

• Servers support both Web based tool and Iperf based tool

• Tools available via anonymous ftp from: achilles.ctd.anl.gov/pub/web100-tools

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Usage Statistics (July 22, 2002)

Top Level Domain Names1500 entries

ccTLD9%

org 1%

net 31%

mil 0%

gov 23%

edu 13%

com 14%

noDNS9%

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Future plans

• Better estimate of path Bandwidth– receiver side packet pair arrivals– ACK packet timings

• Explore receiver side statistics

• Explore Gigabit Ethernet issues

• Identify partners/collaborators

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Caveats

• Server needs time between tests (~90 sec)

• Analysis messages need to be validated

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Demo

http://miranda.ctd.anl.gov:7123

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Obtaining the test results

• Runs 10 sec test from Client to Server– no diagnostic data collected

• Runs 10 sec test from Server to Client– Web100 diagnostic data collected at end of test

• Prints out summary status message– Link speed and duplex– Informational or Warning messages

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Analyzing the test results

• Statistics button– Send and Receive throughput achieved– Details for 5 configuration tests (link type,

duplex mode, congestion, excessive errors, duplex mismatch condition)

– Throughput limits section (%S-R-N limited, RTT, %loss, %out-of-order)

– ‘Tweakable’ settings (TCP modifications to improve performance)

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Analyzing the test results

• More Details button– Individual TCP counters collected by Web100– Conditional test parameters– Throughput analysis section including

theoretical limits, bandwidth*delay products, loss rate, and buffer sizes

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Analyzing the test results

• Report Problem button– Invokes local email client <mailto:>– Automatically inserts collected data into body

of email– Provides “comment” section for user feedback

• Server logs all counter variables used for condition tests