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description
PingER: Actively measuring the worldwide Internet’s end-to-end performance
Les CottrellSLAC
Workshop at the University of Malaya in Kuala Lumpur , June 24-25, 2013
AgendaUsing PingER measurements going back to 1998 and covering 168 countries, this talk will illustrate, Internet performance worldwide.
•Brief history
•How can the Internet help development?
•How does PingER measure Internet performance?
•What do we measure, what does it tell us?
•What do we find?
•Case studies illustrating PingER
•Managing PingER
History• Story of Ping
• Early PingER
• Extension to Developing Regions
• Extension to Pakistan
• Extension to Malaysia
The start• Ping tool invented by Mike Muuss
– “a little thousand-line hack” during a single evening to troubleshoot “odd behavior” on the computer network at the U.S. Army’s Ballistic Research Laboratory in Maryland.
– sent a small data packet known as an echo request to an IP address, typically a remote server or network node. If the target address was reachable, it echoed back the same data, and the program recorded the time it took for the round-trip journey.
– Reminded Muuss of the percussive sound pulse sonar systems use to detect objects underwater, he named it after that sound—ping
• Now defined by RFC 792
5 Joint Techs: I2 & ESnet,Stanford
Measurement Mechanism: PingER
Internet
10 ping request packets each 30 mins
RemoteHost(typicallyweb server)
>ping remhost
Ping response packets
Measure Round Trip Time & Loss
Monitor Host
6
Early PingER• As the head of networking at SLAC, I set up the
system using ping simply to test connections between the laboratory and several dozen research institutions in about a dozen countries that were collaborating on a physics experiment known as BaBar to study properties of subatomic particles.
• Over the next half-decade, as word of PingER’s value spread, I extended monitoring to hundreds more physics laboratories and science centers across the globe. But the project didn’t take a humanitarian turn until 2001.
•UNIMAS
Workshop, Sarawak, Dec 2012
7
Extension to the Developing regions• In 2001 I visited ICTP in Italy.• Driven by ICTP’s goals of bringing first-class science
and technology to developing countries they wanted to know how well the networks were working.
• The simple PingER project was the perfect tool for the job. Ubiquitous ping so nothing to install at remote targets.
• They offered to help expand the project to those parts of the world that needed it most.
• Within the next year, we began establishing monitoring and target hosts in countries as diverse as Ecuador, Rwanda, Jordan, and Bhutan.
UNIMASWorkshop, Sarawak, Dec 2012
8
Extension to Pakistan• In 2004 set up joint agreement with NUST in Pakistan• Soon got my first real glimpse of just how much of a
difference PingER can make. – Set up a PingER monitoring site in the country to
assess performance on the then year-old Pakistan Educational Research Network (PERN).
– The network’s providers touted its bandwidth of 155 Mbps, impressive at the time. But PingER revealed that the “last mile” links to universities were dreadful. These bottleneck connections funneled data at no more than 1 Mbps, causing long delays and high packet loss.
UNIMASWorkshop, Sarawak, Dec 2012
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Extension to Pakistan
• He clearly took PingER’s lessons to heart. When construction of PERN2 began in 2009, its plans included extending high-speed, 1-Gbps data links all the way to university data centers
UNIMASWorkshop, Sarawak, Dec 2012
• During a visit to the university, I presented our findings to the chairman of Pakistan’s higher education commission, Atta-ur-Rehman, who was preparing to fund the next major upgrade to PERN.
10
Extension to Malaysia
• Have set up an official signed MoU between SLAC & U of Malaysia in Sarawak (UNIMAS)
• Idea was to replicate the NUST project
• Fortnightly meetings by Skype
• Just getting started, no students yet
• Met with Vice Chancellor (VC) at one meeting
• This workshop is a follow up.
UNIMASWorkshop, Sarawak, Dec 2012
11
Why do measurements of the Internet matter
UNIMASWorkshop, Sarawak, Dec 2012
Why does it matter
• African scientists isolated
• Lack critical mass
• Need network to collaborate but it is terrible
• Brain drain
• Brain gain, tap diaspora
• Blend in distance learning
• Provide leadership, train trainers
12
Internet Users 2002
Cartograms from:www.geog.qmw.ac.uk/gbhgis/conference/cartogram.html
Tertiary Education fromhttp://www.worldmapper.org/
13 eGY Africa 2012Workshop, Nairobi Oct 2012
How does the Internet help• Investment in information technology plays the role of
a "facilitator" that allows other innovations to take place. http://findarticles.com/p/articles/mi_m1093/is_3_45/ai_86517828/
• World Bank / IFC report: for every 10% increase in high-speed Internet connections there is an increase in economic growth of 1.3 percentage points. April 2010. http://www.infodev.org/en/Article.522.html
• Example: Uganda 15% increase in price of maize based on improved farmer bargaining power. www.itu.int/ITU-D/.../S1-01-NG-ICT_Indicators-Tim_Kelly.pptx
14
How does PingER work
• Mechanism
• Coverage
UNIMASWorkshop, Sarawak, Dec 2012
15 Joint Techs: I2 & ESnet,Stanford
Measurement Mechanism: PingER
Internet
10 ping request packets each 30 mins
RemoteHost(typicallyweb server)
>ping remhost
Ping response packets
Measure Round Trip Time & Loss
On
ce a Day
Uses ubiquitous ping
Monitor Host
Repositories
NUST
16
Deployment• Monitors > 90 in 23 countries, 4 in Africa
Summer Joint TechsStanford, July 2012
• Beacons monitored by most monitors (~100)• Remote sites monitored by some monitors (~750)
17
Metrics Available from PingER• UnReachability
• Minimum RTT
• Average RTT
• Jitter
• Loss
• Derived throughput
• MOS
• Directness of Connection
• OthersUNIMAS
Workshop, Sarawak, Dec 2012
18 eGY Africa 2012Workshop, Nairobi Oct 2012
Unreachability
Summer Joint TechsStanford, July 2012
Unreachability: e.g. N. African uprisings Jan ‘11
NARSS (Cairo)
Helwan (Cairo)
EUN (Cairo)
23:59 Jan 28
23:59 Jan 27
12:00 Jan 27
• Impact varied: start time, recovery time, after effects• Egypt University Network (EUN) down least time
– NARSS via AlterNet->Italy->Egypt, Helwan &EUN via PCCW Global
• Libya first went dark 06:00 Feb 19 for 3 days, then again on Mar 4th more permanently
• Algeria, Morocco, Tripoli not noticeable
=No pings respond
19
Average Round Trip Time (RTT)• Mainly a distance related, but also congestion (i.e. at
the edge)
• For real-time multimedia (H.323) traffic RTT: 0-300ms =Good, 300-600ms=Acceptable, and > 600ms= poor.
UNIMASWorkshop, Sarawak, Dec 2012
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Minimum RTT history by region• Minimize effects of congestion and queuing
UNIMASWorkshop, Sarawak, Dec 2012
21 UNIMASWorkshop, Sarawak, Dec 2012
•GEOS (Geostationary Earth Orbit Satellite)–Good coverage, but expensive in $/Mbps–& long delays min RTT >450ms easy to spot
N.b. RTTs > 250 ms bad for VoIP
Impact of GEOS vs. TerrestrialGEOSGEOS
Demo
22 UNIMASWorkshop, Sarawak, Dec 2012
Conversion history by country seen by min-RTT
Demo
23
Jitter• Mainly at edges, critical for real time: VoIP, gaming• Exponential improvement (factor 10 in 6 yrs.)• The optimum amount of one way latency is 11 ms for keeping time in
music. – Above that delay and they tend to slow down. – >50-70 ms performances tended to completely fall apart.
UNIMASWorkshop, Sarawak, Dec 2012
• For real time haptic control and feedback for medical operations <=80ms is needed.
N. America, Europe, E Asia & Oceania < 1msAfrica, S. Asia & S.E. Asia worst off
24 Summer Joint TechsStanford, July 2012
• Low (<1%) losses are good.• Huge impact on data transfer times (due to timeouts)• Real time impact due to recovery timeouts, e.g. echoing typing• Losses are mainly at the edge, so often distance independent• Losses improving roughly exponentially, ~factor 100 in 12 years
24
Loss has Similar
behavior to thruput
• Best <0.1%: N. America, E. Asia, Europe, Australasia
• Worst> 1%:• Africa & C. Asia
Loss
25 UNIMASWorkshop, Sarawak, Dec 2012
Summer Joint TechsStanford, July 2012
Derived ThroughputDerived throughput ~ 8*1460/(RTT*sqrt(loss))
Mathis et. al
Europe, E. Asia & Australasia merging
Behind Europe:
4 yrs: Russia, 7 yrs:L America,
M East, SE Asia
11 yrs.: India, C. Asia
13 yrs.: Africa
26
• ITU metric, based on quality of a conversation– Originally people listen and give quality 1-5– Can derive from RTT, jitter and loss
UNIMASWorkshop, Sarawak, Dec 2012
MOSMean Opinion Score MOS)
• >=4 is good,
• 3-4 is fair,
• 2-3 is poor.
Important for VoIP
Usa
ble
From the PingER project http://www-iepm.slac.stanford.edu/pinger
27 UNIMASWorkshop, Sarawak, Dec 2012
Directness of connection (Alpha)• Alpha to allow for delays in network equipment &
indirectness of actual route. D = 1 way distance• Distance=D(km)=Alpha*[RTT(msec)*100(km/msec)]– Alpha = D(km) / (min_RTT[msec] * 100 [km/msec])
• If know lat/long of monitor and remote host then know D, so with min-RTT can estimate Alpha– Max(Alpha) =1 = direct (great circle) route and no
network delays– Alpha > 1 probably identifies bad lat/long
coordinates for hosts.– Low values typically mean very indirect route, or
satellite or slow connection (e.g. wireless)– Alpha typically ~ 0.45
28 UNIMASWorkshop, Sarawak, Dec 2012
S.E. Asia Directivity
UNIMASWorkshop, Sarawak, Dec 2012
UNIMAS to …W MY A~0.45
•->PH via JP A~0.22
•->ID via HK A~0.17
•->TH via SG A~0.3
•->BR via ? A~0.07
•->KH via HK-VN A~0.16
•->SG A~0.23
Need measurements from W MY + routing info
TEIN3Trans Eurasia Info Net
29 UNIMASWorkshop, Sarawak, Dec 2012
Alpha worldwide
• Interest in Polar route with Global warming
Summer Joint TechsStanford, July 2012
Alpha=0.71A
lpha
=0.7
3
Alpha
=0.7
3SLAC
JP
AU
NZ
NSK.RU
TW0.180.16IN
DE
EG0.34
JP0.32
o.41
AU0.53
30
• Big improvements for C Asia, S Asia & Australasia
UNIMASWorkshop, Sarawak, Dec 2012
Directivity (Alpha) from SLAC to world
Summer Joint TechsStanford, July 2012
More stable year to year as add more hosts
31
Other metrics• Duplicate packets (try ping www.cern.ch, load
balancing?)
• Out of order packets (parallel paths)
• Conditional Loss Probability (non-random loss)
– one packet is lost the following packet is also lost– route change, loss of sync, spanning tree
reconfiguration
• Maximum packet loss (useful for buffer bloat?)
32
S.E. Asia
• Just started mining early data
• Where does Malaysia sit
• How much variation in SE Asia
• Variation in Malaysia
• Troubles at UNIMAS
• Top and bottom 3 sites monitored in Malaysia
UNIMASWorkshop, Sarawak, Dec 2012
33
Malaysia vs. Other Regions
UNIMASWorkshop, Sarawak, Dec 2012
34
Variation between SE Asian countries
• Factor of 10 between Singapore and Laos
• Singapore 4x better than next countries
• Exponentially improving with time
• On its ownSingaporeapproachesE Asia.
UNIMASWorkshop, Sarawak, Dec 2012
35
Avg-RTT, jitter & loss by Malay State• Need low values of all 3 metrics
• RTTs similar, big diffs in jitter & loss
• Allianze UniColl looks bad
• UTP next worst loss
UNIMASWorkshop, Sarawak, Dec 2012
Seen from SLAC, Nov 2012
36
Non lossy Malaysian hosts seen from SLAC Nov 2012
UNIMASWorkshop, Sarawak, Dec 2012
UNIMAS
MIMOS
MIMOS
UNISZA
Note monitoring host (SLAC) down
37
OCESB
Lo
ssy
ho
st s
een
fro
m S
LA
C N
ov
2012
UPSI
UTEM
MIU
AIU
Sabah
38
Diving deeper: packet loss Nov 27-28• Allianze University College unreachable• UTEM, MIU, UPSI, OCESB, AIU, SABAH experienced loss Nov
26• No PingER loss from the rest on Nov 26: Johor, Kelantan, KL,
Nigeri Sembilan, Sarawak, Terengganu
UNIMASWorkshop, Sarawak, Dec 2012
1930-midnight MST, backup?
UTEMLosses isolated, not correlated with large RTT
39
Another host, large RTTs correlate with time of day
UNIMASWorkshop, Sarawak, Dec 2012
40
UNIMAS Jitter
UNIMASWorkshop, Sarawak, Dec 2012
UNIMAS to
MalaysiaJitter
AllianzeUniversity
College
Universiti TechnologiPetronas
41
Why not show UNIMAS to Malaysia more
• Big changes in RTT affect throughput especially for Kuching
• UNIMAS was seeing congestion – This would be seen everywhere– Turn on shaping– Removes loss &
day-night variations
UNIMASWorkshop, Sarawak, Dec 2012
2
1RT
T m
s
Background loss colors
SLAC to UNIMAS Oct-Nov 2012
42 UNIMASWorkshop, Sarawak, Dec 2012
Increase of capacity to UNIMAS from 200Mbps to 500Mps
UNIMASWorkshop, Sarawak, Dec 2012
Huge spikes removed
43 UNIMASWorkshop, Sarawak, Dec 2012
UNIMASWorkshop, Sarawak, Dec 2012
Improvement
44
Unreachable Malaysian hosts
• Unreachable from SLAC Nov 1-26, 2012:1. 92% Allianze University College
2. 20% www.ocesb.com.my (Speedtest)
3. 17% Universiti Teknologi Petronas, Bandar Seri Iskandar
4. 4% University Malaysia Kelantan
• 100% Reachable– MIMOS, UNIMAS, Sultan Zainal Abidin University,
USIM, University Teknologi Malaysia, Sultan Idris University of Education
UNIMASWorkshop, Sarawak, Dec 2012
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Case Study Africa
UNIMASWorkshop, Sarawak, Dec 2012
46
Submarine Cables
2012
1 cable, W Coast only, No competition (340Gb/s)
World Cup S Africa 2008 led to many submarine cables connecting Africa to rest of the worldCapacity, shorter RTT, competitionMost cables are now activeFuture Cables promise connectivity:
ACE Q3 2012: France-Spain-Morocco & many African countries
SAex 2014: Brazil-Angola-SA WASACE 2014: France-US-Brazil-Nigeria-
Angola-SABRICS 2014: Brazil-SA-Mauritius-India-
China-RussiaCable capacity increase from 0.34Tb/s in
2008 to 87.5 Tb/s by 2014 (factor ~3000)http://manypossibilities.net/african-undersea-cables
/
2008
47 Summer Joint TechsStanford, July 2012
Min-RTT satellite vs. fibre
2010
2009
2008
OK
to
US
48
Comparison in minimum from SLAC to African Countries in 2008 and 2012.
UNIMASWorkshop, Sarawak, Dec 2012
2008 2012800
600
400
200
0
800
600
400
200
0TerrestrialTerrestrial
GEOS GEOS
Minimum RTT from SLAC to African Countries 2008 vs.. 2012
Min
RT
T (
ms)
Note the countries that have gone from GEOS to terrestrial
49
RTT
Summer Joint TechsStanford, July 2012
• Angola step mid-May, more stable
• Zambia one direction reduce 720>550ms– Unstable, still
trying?• Tanzania, also
dramatic reduction in losses
• Uganda inland via Kenya, 2 step process
• Rwanda Sep 25• Many sites still
to connect
750ms750ms 450ms450ms
Aug 20Aug 20
SLAC to AngolaSLAC to Angola
SLAC to ZambiaSLAC to Zambia
SLAC to TanzaniaSLAC to Tanzania
SLAC to UgandaSLAC to Uganda
1 direction1 direction
Both directionsBoth directions
Sep 27Sep 27
1 direction1 direction Both directions?Both directions?
RTT, e.g. changes in 2009
50
Intra Africa Optical Fibre Networkhttp://www.ubuntunet.net/fibre-map
Summer Joint TechsStanford, July 2012
Just as important as the submarine cables serving the coasts, are the tens if not hundreds of millions of dollars being invested in new terrestrial fiber to move this capacity inland.
51
Other 3 billion (O3b)• Refers to population of world without
broadband
• Constellation of 8 Medium Earth Orbit satellites at altitude 8000km
• Min RTTs factor of 4 less than GEOS – ~125ms, similar to inter-continent land lines
• Backed by SES World Skies, HSBC, Google…
• Launch 2013
eGY Africa WorkshopNairobi Oct 2012
52
Differences within Africa• Southern Africa now leads, caught North • Central is worst off• Notice improvement since 2008
– satellite=> terrestrial, competition
eGY Africa 2012Workshop, Nairobi Oct 2012
Derived throughput from SLAC to African regions
• Africa improving, catching up?
53
Africa was 16 yrs. behind Europe in 2009
UNIMASWorkshop, Sarawak, Dec 2012
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Africa is now 14 yrs. behind Europe in 2012
UNIMASWorkshop, Sarawak, Dec 201214 years
55
Africa might catch up with Europe in 20 years at current rate of improvement
UNIMASWorkshop, Sarawak, Dec 2012
Was falling further behind
70 times w
orse
26 years beh
ind
Eu
rop
e
56
• By 2011 prices had dropped only factor of 2– Alternative fibre often owned by electricity
companies, pipelines and not allowed to sell, lease or operate – needs deregulation and is happening
– Business model: ISPs sell to large corporations, gov, edu, NGOs=>small customer base to recover costs from =>high prices
• WiFI & Mobile to the rescue, overlay 3G with fibre net
• Alex Twinomugisha originally published |Why Are African Internet Access Prices Still High? on Africa Business Source
Prices
57 eGY Africa 2012Workshop, Nairobi Oct 2012
Then there is the cost
58
Africa Broadband costs vs. rest of the world
UNIMASWorkshop, Sarawak, Dec 2012
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NRENs in Africa
eGY Africa WorkshopNairobi Oct. 2012
With connection to GÉANT going live end 2012, UbuntuNet will provide sub-Saharan Africa with infrastructure for global, and regional research collaboration and e-learning
N. Africa connected via EUMED to Europe. Also Arab States REN formed 1 year ago
From PingER Project
60
Traceroutes from S Africa & Burkina Faso in 2009
UNIMASWorkshop, Sarawak, Dec 2012
Despite having NRENs & terrestrial fibres along both East & West coasts of Africa connecting to most maritime countries, still most inter-African routes went via Europe and N America
Not only did this add large delays, but also resulted in costly inter-continental rates
61
Setting up IXPs for better connectivity
UNIMASWorkshop, Sarawak, Dec 2012
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Opportunities: Square Kilometre Array (SKA)
Summer Joint TechsStanford, July 2012
• Build in in Sub-Saharan states with cores in South Africa and Australia,
• €1.5 billion, construction start 2016, initial observations 2019
“…equivalent to ten times the global internet traffic today”
“…equivalent to ten times the global internet traffic today”
63
Opportunities: Continued• Aug 30, 2012: 220 donated computer servers
from CERN, Switzerland, will start a journey to be delivered to the Kwame Nkrumah University of Science and Technology in Ghana.– This will provide a new computing center for
KNUST and boost African physics onto the international stage, helping African students, e.g. enable participation in simulations of LHC data.
• Strategic plan for a synchrotron light source in southern Africa – 2 day workshop Dec 2011, Pretoria– http://indico.saip.org.za/conferenceDisplay.py?ovw=True&confId=12
64
More Information
• Case Study– https://confluence.slac.stanford.edu/display/IEPM/N
ew+E.+Coast+of+Africa+Fibre
• Telegeography submarine cable map– http://www.submarinecablemap.com/
• Africa Undersea Cables– http://manypossibilities.net/african-undersea-cables/
• Ubuntunet– http://www.ubuntunet.net/fibre-map
eGY Africa WorkshopNairobi, Oct. 2012
65
Mediterranean Cable Cut
• See https://confluence.slac.stanford.edu/display/IEPM/Effects+of+Fibre+Outage+through+Mediterranean
UNIMASWorkshop, Sarawak, Dec 2012
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Mediterranean Fibre Cuts Jan 31, 2008• 2 major cables: SEAMEW4, FLAG cut off
Marseilles and Alexandria
• Traffic falls over to SEAMEW3
• SEAMEW3 congested, resulted in doubling RTTs, increased jitter & Loss
• Start between 6:47am and 7:16am GMT• Reduced bandwidth by over 50% to over 20 countries
UNIMASWorkshop, Sarawak, Dec 2012
200=>400msmsLost connectionSLAC to tanta.edu.eg800
6004002000
RT
T m
s
67
Affected many countries
UNIMASWorkshop, Sarawak, Dec 2012
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Impact on loss lasted several days
UNIMASWorkshop, Sarawak, Dec 2012
Afr
ica
M E
ast
S A
sia
SE
A
sia
69
World events Case studies
• Japanese Earthquake & Tsunami, 2011– https://confluence.slac.stanford.edu/display/IEPM/J
apanese+Earthquake+March+11th%2C+2011
• Chilean Earthquake 2010– https://confluence.slac.stanford.edu/display/IEPM/C
hilean+Earthquake+Feb+27th%2C+2010
• Syria Nov 29, 2012– https://confluence.slac.stanford.edu/display/IEPM/S
yria+shuts+down+its+Internet+connection UNIMAS
Workshop, Sarawak, Dec 2012
70
Effect of Japanese Earthquake & Tsunami March 11, 2011
UNIMASWorkshop, Sarawak, Dec 2012
2001000
RT
T (
ms)
SLAC to KEK
Traffic rerouted Eastwards
71
Chilean earthquake, Feb 27, 2010
• Telmex is an Internet service provider in Chile so it should have better connectivity than most organizations. The plot shows lack of connectivity (black), losses (colored background, see the legend below) and median RTT. The loss of connectivity following the earthquake at 6:34am UTC on February 27th is apparent. Connectivity was re-established at about 9:30pm (UTC) that evening followed by considerable instability.
UNIMASWorkshop, Sarawak, Dec 2012
72
Syria shuts down Internet, Nov-29-12• Renesys reported:
– Starting at 10:26 UTC on Thursday, 29 November (12:26pm in Damascus), Syria's international Internet connectivity shut down.
• Prior to this working well
SLAC to Thawra Online
100
200
0
mse
c
12:00:0000:00:0012:00:0000:00:0012:00:00
SLAC to iNET
100
200
0
mse
c
Source: PingER
29 Nov ‘12
Damascus
iNET
73
Other uses
UNIMASWorkshop, Sarawak, Dec 2012
74
Trouble shooting
• Identify when RTT etc. changed (or did not)
• Has congestion increased (jitter, diurnal changes)
• Is it worse than similar paths
• Is it related to a route change?– Also keep daily traceroutes
• Identify that it is no longer a problem
• Identify problem sites to focus on
UNIMASWorkshop, Sarawak, Dec 2012
75
Choosing ISP
• Choosing a service provider given a choice:– For SLAC ESnet vs. Internet2
• Got ISP to change routing to keep our business
– Choice of a DSL provider for residential coverage in Bay Area
UNIMASWorkshop, Sarawak, Dec 2012
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Comparison to UN ITU ICT Development Index
UNIMASWorkshop, Sarawak, Dec 2012
100
1000
10000
ICT Development Index from the UN International Telecommunications Union
2 4 6 810
Pin
gER
Der
ived
thr
ough
put
(kbi
ts/s
ec)
Bubble size = Population
Demo
77
Malaysian and Brunei sites monitored from UNIMAS
eGY Africa 2012Workshop, Nairobi Oct 2012Demo
78
UNIMAS to SE. Asia
eGY Africa 2012Workshop, Nairobi Oct 2012
CambodiaThailand
Philippines
79
Viewing data
eGY Africa 2012Workshop, Nairobi Oct 2012
• Pingtable.pl– Select metric, tick, source, destination etc– Table downloadable for Excel– Details on hosts, and graphs of performance
• Table of country to country connections
• Map– See monitors, beacons, remotes– Select metric, src, dst, draw colored lines
connecting, colors = metric value– Graphs of metric and pinger hosts per country
• Maps of metric performance by Country
• Google Explorer and motion charts
80
Managing• Site map
– Introductions
• Meta database– Oracle database => perl require script and
pinger.xml files
• Data gathering status
• Measurements:– Run from cronjob each 30 mins
• Spotting anomalies, hosts with same IP addr, hosts with missing information (country, lat/lon
• Finding hostseGY Africa 2012
Workshop, Nairobi Oct 2012
81
Problems• Hosts change IP address
– Maybe v frequent, e.g. a cluster or slowly as host with same name is replaced with a new host with new IP address.
• Hosts not where you think they are
• No packet loss how to calculate Throughput ~ 1460(bytes)*8(bits)/(RTT*sqrt(loss))
• Throughput approx. only good for TCP Reno– OS’ such as Windows, Linux now allow other
congestion control algorithms
eGY Africa 2012Workshop, Nairobi Oct 2012
82
Joining • ~ 85 active monitors worldwide
– https://confluence.slac.stanford.edu/display/IEPM/Installation+Overview gives the state
• Invitation letter for monitoring sites– http://www-iepm.slac.stanford.edu/pinger/letters/invite-monit
or.doc
• Host requirements– http://www-iepm.slac.stanford.edu/pinger/tools/mon-req.html
• Download site for application etc.– Traceroute/ping server– Pinger2.pl measuring engine– https://confluence.slac.stanford.edu/display/IEPM/Installation
+Overview
83
Demo• Interactive demonstrations of the data mining
capabilities of public data sources provided by organizations such as the UN and ITU coupled with monitoring data from PingER
• http://www-iepm.slac.stanford.edu/pinger/explorer.html
Summer Joint TechsStanford, July 2012
84 UNIMASWorkshop, Sarawak, Dec 2012
More Information• PingER web home page
– http://www-iepm.slac.stanford.edu/pinger/
• Tutorial on network monitoring & PingER– http://www.slac.stanford.edu/comp/net/wan-mon/tutorial.html
• PingER data Explorer– www-iepm.slac.stanford.edu/pinger/explorer.html
• PingER Project site map– http://www-iepm.slac.stanford.edu/pinger/site.html
• Invitation to join– www-iepm.slac.stanford.edu/pinger/letters/invite-
monitor.doc
85 eGY Africa 2012Workshop, Nairobi Oct 2012