International Committee for Future Accelerators (ICFA)

Standing Committee on Inter-Regional Connectivity (SCIC)

Chairperson: Professor Harvey Newman, Caltech








ICFA SCIC Network Monitoring Report









Prepared by the ICFA SCIC Monitoring Working Group

On behalf of the Working Group:
Les Cottrell



January 2007 Report of the ICFA-SCIC Monitoring Working Group

Edited by R. Les Cottrell and Shahryar Khan on behalf of the ICFA-SCIC Monitoring WG

Created January 7, 2007, last update January 15, 2007

ICFA-SCIC Home Page | Monitoring WG Home Page

This report is available from


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January 2007 Report of the ICFA-SCIC Monitoring Working Group. 2

Executive Overview.. 4

Introduction. 5

ICFA/SCIC Network Monitoring Working Group. 5

Goals of the Working Group. 6

Methodology. 6

PingER Results. 7

Deployment 7

Metric Meanings. 8

Loss. 9

RTTs. 14

Throughput 16

View from Europe. 17

Yearly Throughput Trends. 18

Variability of performance between and within regions. 19

Comparisons with Economic and Development Indicators. 21

Case Study on NIIT, Pakistan. 25

Conclusions for Pakistan. 27

Africa and South Asia: Comparison between Min and Avg. RTTs. 28

Case Study for Africa. 29

High Performance Network Monitoring. 34

IEPM-BW Results. 34

New Monitoring and Diagnostic Efforts in HEP.. 35

LHC-OPN Monitoring. 37

Related HEP Network Research. 37

Comparison with HEP Needs. 37

Accomplishments since last report 38

Efforts to Improve PingER Management 39

TULIP- IP Locator Using Triangulation. 39

PingER Host Searching Tool 39

PingER Validation Toolkit 40

PingER Executive Plots. 40

ViPER (Visualization for PingER) 41

Digital Divide Publications/Presentations: 43

Talks (Most recent first) 43

Recommendations. 43

Appendix: Countries in PingER Database. 44

Acknowledgements. 45

References. 45

Executive Overview

Internet performance is improving each year with througputs typically improving by 40-50% per year and losses by 25%-45% per year, and for some regions such as S. E. Europe, even more. Geosynchronous satellite connections are still important to countries with poor telecommunications infrastructure and for outlying areas. However, the number of countries with fiber connectivity has and continues to increase and in most cases, satellite links are used as backup or redundant links. In general for HEP countries satellite links are being replaced with land-line links with improved performance (in particular for RTT). On the other side of the coin Internet usage is increasing (see, the application demands (see for example [bcr]) are growing and the expected reliability is increasing, so we cannot be complacent.

In general, throughput measured from within a region is much higher than when measured from outside. Links between the more developed regions including N. America[1], Japan and Europe are much better than elsewhere (3 - 10 times more throughput achievable). Regions such as Russia, S.E. Asia, S.E. Europe and Latin America are 3-6 years behind. Russia and S.E. Asia are catching up slowly. However, Africa, S. Asia and C. Asia are 8-10 years behind and even worse appear to be falling further behind. Looking forward ten years to 2016, if the current rates of progress continue, then performance from N. America to Africa will be 1000 time worse than to Europe,  to S. Asia and C. Asia will be 100 times worse than to Europe.

Africa and South Asia are two regions where the internet has seen phenomenal growth, especially in terms of usage. However, it appears that network capacity is not keeping up with demand in these regions.  In fact many sites in Africa and India appear to have throughputs less that that of a well connected (cable, DSL or ISDN) home in Europe or Anglo America. Further the end-to-end networking is often very fragile both due to last mile effects and poor infrastructure (e.g. power) at the end sites, and also due to lack of adequate network backup routes. Africa is a big target of opportunity with 915 million people and a 625% growth in number of Internet users from 2000-2006. However, there are many challenges including lack of power, import duties, lack of skills, disease and protectionist policies. In almost all measurements Africa stands out as having the poorest performance and even worse is falling behind much faster than any other region. Further Africa is a vast region and there are great differences in performance between different countries and regions within Africa.

There is a strong positive correlation between the Internet performance metrics and various economic and development indices available from the UN and ITU. Besides being useful in their own right these correlations are an excellent way to illustrate anomalies and for pointing out measurement/analysis problems. The large variations between sites within a given country illustrate the need for careful checking of the results and the need for multiple sites/country to identify anomalies. Also given the difficulty of developing the human and technical indicators (at best they are updated once a year and usually much less frequently), having indicators such as PingER that are constantly and automatically updated is a useful complement.

For modern HEP collaborations and Grids there is an increasing need for high-performance monitoring to set expectations, provide planning and trouble-shooting information, and to provide steering for applications.

To quantify and help bridge the Digital Divide, enable world-wide collaborations, and reach-out to scientists world-wide, it is imperative to continue and extend the PingER monitoring coverage to all countries with HEP programs and significant scientific enterprises.


This report may be regarded as a follow on to the May 1998 Report of the ICFA-NTF Monitoring Working Group [icfa-98], the January 2003 Report of the ICFA-SCIC Monitoring Working Group [icfa-03], the January 2004 Report of the ICFA-SCIC Monitoring Working Group [icfa-04], the January 2005 Report of the ICFA-SCIC Monitoring Working Group [icfa-05] and the the January 2006 Report of the ICFA-SCIC Monitoring Working Group [icfa-06].

The current report updates the January 2006 report, but is complete in its own right in that it includes the tutorial information from the previous reports.  The main changes in this year’s reports are:

·        Figures 1-6, 8-10 and 13 and Tables 1, 2, 4 and 6 have all been updated

·        The text related to all the above tables and figures has been updated.

·        Sections have been added on:

o       A Case Study for Africa

o       LHC-OPN Monitoring

o       Related HEP research

o       Tools to manage, analyze and visualize the PingER data

§         PingER Host search tool

§         PingER Executive plots

§         ViPER visualization

§         PingER data validation and management

§         Tools to validate the PingER data

·        Figures 22-25 are new.

·        We have updated the section on PingER publications and talks.

ICFA/SCIC Network Monitoring Working Group

The formation of this working group was requested at the ICFA/SCIC meeting at CERN in March 2002 [icfa-mar02]. The mission is to: Provide a quantitative/technical view of inter-regional network performance to enable understanding the current situation and making recommendations for improved inter-regional connectivity.

The lead person for the monitoring working group was identified as Les Cottrell. The lead person was requested to gather a team of people to assist in preparing the report and to prepare the current ICFA report for the end of 2002. The team membership consists of:

Table 1: Members of the ICFA/SCIC Network Monitoring team

Les Cottrell



Richard Hughes-Jones

University of Manchester


Sergei Berezhnev

RUHEP, Moscow State.Univ.


Sergio F. Novaes


S. America

Fukuko Yuasa


Japan and E. Asia

Shawn McKee


I2 HEP Net Mon WG

Goals of the Working Group

·         Obtain as uniform picture as possible of the present performance of the connectivity used by the ICFA community

·         Prepare reports on the performance of HEP connectivity, including, where possible, the identification of any key bottlenecks or problem areas.


There are two complementary types of Internet monitoring reported on in this report.

1.      In the first we use PingER [pinger] which uses the ubiquitous "ping" utility available standard on most modern hosts. Details of the PingER methodology can be found in the May 1998 Report of the ICFA-NTF Monitoring Working Group [icfa-98] and [ejds-pinger]. PingER provides low intrusiveness (~ 100bits/s per host pair monitored[2]) Round Trip Time (RTT), loss, reachability (if a host does not respond to a set of 21 pings it is presumed to be non-reachable). The low intrusiveness enables the method to be very effective for measuring regions and hosts with poor connectivity. Since the ping server is pre-installed on all remote hosts of interest, minimal support is needed for the remote host (no software to install, no account needed etc.) 

2.      The second method (IEPM-BW [iepm], perfSONAR [perfSONAR] etc.) is for measuring high network and application throughput between hosts with excellent connections. Examples of such hosts are to be found at HEP accelerator sites and tier 1 and 2 sites, major Grid sites, and major academic and research sites in N. America2, Japan and Europe. The method can be quite intrusive (for each remote host being monitored from a monitoring host, it can utilize hundreds of Mbits/s for ten seconds to a minute each hour). It also requires more support from the remote host. In particular either various services must be installed and run by the local administrator or an account is required, software (servers) must be installed, disk space, compute cycles etc. are consumed, and there are security issues. The method provides expectations of throughput achievable at the network and application levels, as well as information on how to achieve it, and trouble-shooting information.

PingER Results


The PingER data and results extend back to the start of 1995. They thus provide a valuable history of Internet performance. PingER has over 30 monitoring nodes in 14 countries, that monitor over 700 remote nodes at over 600 sites in around 120 countries (see PingER Deployment [pinger-deploy]). These countries contain over 89% of the world's population (see Table 2) and over 99% of the online users of the Internet. Most of the hosts monitored are at educational or research sites. We try and get at least 2 hosts per country to help identify and avoid anomalies at a single host, although we are making efforts to increase the number of monitoring hosts to as many as we can. The requirements for the remote host can be found in [host-req]. Fig. 1 below shows the locations of the monitoring and remote (monitored sites).

Figure 1: Locations of PingER monitoring and remote sites as of Jan 2007.

There are over two thousand monitoring/monitored-remote-host pairs, so it is important to provide aggregation of data by hosts from a variety of "affinity groups". PingER provides aggregation by affinity groups such as HEP experiment collaborator sites, Top Level Domain (TLD), Internet Service Provider (ISP), or by world region etc. The world regions, as defined for PingER, and countries monitored are shown below in Fig. 2. The regions are chosen starting from the U.N. definitions [un]. We modify the region definitions to take into account which countries have HEP interests and to try and ensure the countries in a region have similar performance.

Figure 2: Major regions of the world for PingER aggregation by regions

More details on the regions are provided in Table 2 that highlights the number of countries monitored in each of these regions, and the distribution of population in these regions.

Table 2: PingER Monitored Countries and populations by region Jul-Dec 2006


# of Countries

% of World Population




Central Asia






Latin America



North America



East Asia



South East Asia



South East Europe



South Asia



Middle East












Metric Meanings

To assist in interpreting the results in terms of their impact on well-known applications, we categorize the losses into quality ranges.  These are shown below in Table 3.

Table 3: Quality ranges used for loss






Very Poor




>=0.1% &  
< 1%

> =1%
& < 2.5%

>= 2.5%
& < 5%

>= 5%
& < 12%

>= 12%

More on the effects of packet loss and RTT can be found in the Tutorial on Internet Monitoring & PingER at SLAC [tutorial], briefly:

·         At losses of 4-6% or more video-conferencing becomes irritating and non-native language speakers become unable to communicate. The occurrence of long delays of 4 seconds (such as may be caused by timeouts in recovering from packet loss) or more at a frequency of 4-5% or more is also irritating for interactive activities such as telnet and X windows. Conventional wisdom among TCP researchers holds that a loss rate of 5% has a significant adverse effect on TCP performance, because it will greatly limit the size of the congestion window and hence the transfer rate, while 3% is often substantially less serious, Vern Paxson. A random loss of 2.5% will result in Voice Over Internet Protocols (VOIP) becoming slightly annoying every 30 seconds or so. A more realistic burst loss pattern will result in VOIP distortion going from not annoying to slightly annoying when the loss goes from 0 to 1%. Since TCP throughput for the standard (Reno based) TCP stack goes as 1/(sqrt(loss) [mathis]) (see M. Mathis, J. Semke, J. Mahdavi, T. Ott, "The Macroscopic Behavior of the TCP Congestion Avoidance Algorithm",Computer Communication Review, volume 27, number 3, pp. 67-82, July 1997), it is important to keep losses low for achieving high throughput.

·         For RTTs, studies in the late 1970s and early 1980s showed that one needs < 400ms for high productivity interactive use. VOIP requires a RTT of < 250ms or it is hard for the listener to know when to speak.

It must be understood that these quality designations apply to normal Internet use. For high performance, and thus access to data samples and effective partnership in distributed data analysis, much lower packet loss rates may be required.


Of the two metrics loss & RTT, loss is more critical since a loss of a packet will typically cause timeouts that can last for several seconds, moreover, RTT increases with increase in distance between any two nodes and also, with the increase in the number of hops, whereas loss is less distance dependent. For instance RTT between a node at SLAC and somewhere in Europe is expected to be around 160ms.

Figure 3: Jul-Dec ’06 median average monthly packet loss seen from SLAC to the world.

Fig. 3 shows a snapshot of the median average monthly losses from SLAC to the world between July and December 2006. We observe that most countries have low (< 1%) losses, with most of the poor or worse performance being confined to Africa..

Another way of looking at the losses is to see how many hosts fall in the various loss quality categories defined above as a function of time. An example of such a plot is seen in Fig 4.


Figure 4: Number of hosts measured from SLAC for each quality category from February 1998 through December 2006.

It can be seen that recently most sites fall in the good quality category. The numbers at the bottom indicate the percentage of total sites that see good or better packet loss at the start of the year. Also the number of sites with good quality has increased from about 55% to about 75% in the 9 years displayed. The plot also shows the increase in the total number of sites monitored from SLAC over the years. The improvements are particularly encouraging since most of the new sites are added in developing regions.

Towards the end of 2001 the number of sites monitored started dropping as sites blocked pings due to security concerns. The rate of blocking was such that out of 214 hosts that were pingable in July 2003, 33 (~15%) were no longer pingable in December 2003.

The increases in monitored sites towards the end of 2002 and early 2003 was due to help from the Abdus Salam Institute of Theoretical Physics (ICTP). The ICTP held a Round Table meeting on Developing Country Access to On-Line Scientific Publishing: Sustainable Alternatives [ictp] in Trieste in November 2002 that included a Proposal for Real time monitoring in Africa [africa-rtmon]. Following the meeting a formal declaration was made on RECOMMDENDATIONS OF the Round Table held in Trieste to help bridge the digital divide [icfa-rec]. The PingER project is collaborating with the ICTP to develop a monitoring project aimed at better understanding and quantifying the Digital Divide. On December 4th the ICTP electronic Journal Distribution Service (eJDS) sent an email entitled Internet Monitoring of Universities and Research Centers in Developing Countries [ejds-email] to their collaborators informing them of the launch of the monitoring project and requesting participation. By January 14th 2003, with the help of ICTP, we added about 23 hosts in about 17 countries including: Bangladesh, Brazil, China, Columbia, Ghana, Guatemala, India (Hyderabad and Kerala), Indonesia, Iran, Jordan, Korea, Mexico, Moldova, Nigeria, Pakistan, Slovakia and the Ukraine. The increase towards the end of 2003 was spurred by preparations for the second Open Round Table on Developing Countries Access to Scientific Knowledge: Quantifying the Digital Divide 23-24 November Trieste, Italy and the WSIS conference and associated activities in Geneva December 2003.

The increases in 2004 were due to adding new sites especially in Africa, S. America, Russia and several outlying islands. See Fig. 1 and section “Accomplishments since last report”.

In 2005, the Pakistan Ministry Of Science and Technology (MOST) and the US State Department funded SLAC and the National University of Sciences and Technology’s (NUST) Institute of Information Technology (NIIT) to collaborate on a project to improve and extend PingER. As part of this project and the increased interest from Internet2 in “Hard to Reach Network Places” many new sites in the South Asia and Africa were added to increase the coverage in these regions and also to replace sites that were blocking pings. For instance we can find no sites in Angola that are pingable in Dec 2005. Also as part of this project we started to integrate PingER with the NLANR/AMP project and as a result a number of the AMP nodes were added as PingER remote hosts in the developing regions. With help of Duncan Martin and the South Africa Tertiary Education Network (TENET) (, we successfully set up a monitoring node in South Africa, which should be a great help in viewing the Digital Divide from within the Divide. With the help of NIIT (, a monitoring node was set up at NIIT and in Nov’ 05 another one at NTC (National Telecommunication Corporation, which is the service provider for the PERN (Pakistan Educational and Research Network Although it is too early to provide any long terms predictions, more than almost two months of data gathered indicate certain interesting results which will be discussed later in more detail.

Again in 2006 in preparation for a conference on Sharing Knowledge Across the Mediterranean at ICTP Trieste Nov 6-8, 2006, we added many new sites especially in Africa.

Fig. 5 below shows the long term trends for the various regions as seen from N. America.

Figure 5: Packets loss trends from N. America to various regions of the world.

The following general observations can be made for the losses:

·         For most regions the improvement in losses is typically between 25% and 45% per year.

·         The better regions (N. America, Europe, E. Asia and Oceania) are achieving better than 1% packet for most of their sites seen from N. America

·         Africa has the highest loss rates and is falling further behind other regions..

Fig. 6 shows the world's connected population fractions obtained by dividing countries up by loss quality seen from the US, and adding the connected populations for the countries (we obtained the population/country figures from "How many Online" [nua] for 2001 and from CIA World Factbook for 2006 [cia-pop-figures]).

Figure 6: Fraction of the world's connected population in countries with measured loss performance in 2001 and Dec 2006

It can be seen that in 2001, <20% of the population lived in countries with acceptable or better packet loss. By December 2006 this had risen to 53%. The coverage of PingER has also increased from about 50 countries at the start of Jan 2001 to over 120 in December 2006. This in turn reduced the fraction of the connected population for which PingER has no measurements from 49% to 10%. The results are even more encouraging when one bears in mind that the newer countries being added typically are from regions that have traditionally poorer connectivity.

It is interesting to compare the packet losses seen by various regions with those seen by residential DSL customers in the San Francisco Bay Area. This is shown in Fig. 7 below.

Figure 7: Losses from SLAC to various world regions compared with that for residential customers in the San Francisco Bay Area.


There are limits to the minimum RTT due to the speed of light in fibers or electricity in copper. Typically today, the minimum RTTs for terrestrial circuits are about 2 * distance / ( 0.6 * c), or roughly 100km/ms (RTT time,) where c is the velocity of light, the factor of 2 accounts for the round-trip, 0.6*c is roughly the speed of light in fibre. For geostationary satellites links, the minima are between 500 and 600ms. For U.S. cross country links (e.g. from SLAC to BNL) the typical minimum RTT (i.e. a packet sees no queuing delays) is about 70 msec.

Fig. 8 below shows the trends of the min-RTT measured from ESnet sites in the US to the various regions of the world. The straight lines are exponential fits to the data (straight lines on a log-linear plot), and the wiggly lines are the monthly rolling averages.


Figure 8: Minimum RTT measured from the US to sites in regions of the world

South Asia has made substantial improvments in particular moving from satellite to land lines as can be seen in Fig. 9 below. Africa and S. E. Asia are improving. Central Asia on the other hand has been stuck with geo-stationary satellites and so little change is seen for it. Latin America took a huge step down in RTT at the end of 1999 going from mainly satellite (>500ms) to 200ms (i.e. mainly landlines). S.E. Asia looks like a gradual improvement. For most of the other regions the improvemnts are marginal. This is at least partially since upgrading high speed links from say 45 to 155, 622 or 2400 or 10,000 Mbps has a small effect on the minimum RTT, the main effect being the distance.

Fig. 9 shows the RTT from the U.S. to the world in January 2000, December 2003 and December 2006. It also indicates which countries of the world contain sites that were monitored countries not monitored from the US are shown in white).


Figure 9: December 06 comparison of Minimum RTT with 2003 and 2000 results


It is seen that countries such as Argentina and China with satellite links (> 600ms RTT or dark red) in January 2000 have moved to land lines and now have good minimum RTT. Today satellite links are used in places where it is hard or unprofitable to pull terrestrial-lines (typically fibers) to. Barring a few countries in Central and Eastern Africa, Central Asia (Armenia, Azerbaijan, Kazakhstan, Kyrgistan, Tajikistan, Turkmenistan all of which are served by the Silk Road project geostationary satellite link), Cuba and Nepal most of the countries being monitored by PingER now have optical fiber connectivity. The Eastern Africa Submarine Cable System (EASSy [EASSy]) Project has been established to develop and implement a submarine cable system to provide fibre optic telecommunications facilities to the Eastern coast of Africa. The partners include Botswana, Burundi, Djibouti, Ethiopia, Kenya, Madagascar, Mozambique, Rwanda, Somalia, South Africa, Sudan, Zanzibar, Tanzania and Uganda so this could make a big improvement for this area. This cable will also link Northern and Southern African international gateways to the system.


We also combine the loss and RTT measurements using throughput = 1460Bytes[Max Transmission Unit]/(RTT * sqrt(loss)) from [mathis]. The results are shown in Fig. 10. The orange line shows a ~40% improvement/year or about a factor of 10 in < 7 years.

Figure 10: Derived throughput as a function of time seen from ESnet sites to various regions of the world. The numbers in parentheses are the number of monitoring/remote host pairs contributing to the data. The lines are exponential fits to the data.

The data for several of the developing countries only extends back for only about five years so some care must be taken in interpreting the long term trends. With this caveat, it can be seen that links between the more developed regions including N. America, Japan and Europe are much better than elsewhere (3 - 10 times more throughput achievable). Regions such as Russia, S.E. Asia, S.E. Europe and Latin America are 3-6 years behind. Russia and S.E. Asia are catching up slowly. However, Africa, S. Asia and C. Asia are 8-10 years behind and even worse appear to be falling further behind. Looking forward ten years to 2015, if the current rates of progress continue, then performance from N. America to Africa will be 1000 time worse than to Europe,  to S. Asia and C. Asia will be 100 times worse than to Europe.

View from Europe

To assist is developing a less N. American view of the Digital Divide; we added many more hosts in developing countries to the list of hosts monitored from CERN in Geneva Switzerland. We now have data going back for eight years that enables us to make some statements about performance as seen from Europe. Fig. 11 shows the data from CERN as of September 2005. In order to reduce the effect of the 1/RTT in the Mathis formula for derived throughput, we normalize the throughputs by using norm_throughput = throughput * min_RTT(remote region) / min_rtt(monitoring_region). The lines are exponential fits to the data.

Figure 11: Derived throughputs to various regions as seen from CERN. The open square points are the monthly averages for E. Asia and the plus signs (+) are for N. America.

The slow increases for North America and Europe are partially an artifact of the difficulty of accurately measuring loss with a relatively small number of pings (14,400 pings/month at 10 pings/30 minute interval, i.e. a loss of one packet ~ 1/10,000 loss rate). Looking at the data points one can see that the East Asian trend crossing Europe and North America is mainly a result of East Asia starting from a lower throughput which gives a steeper slope to its trendline. Looking at the data points they are seen to overlap for the last two years. Russia, S. E. Europe (Balkans) and Oceania are catching up with Europe, East Asia and North America; the Middle East, Central Asia, Latin America and S. E. Asia are falling behind. Africa on the other hand is falling behind.

Yearly Throughput Trends

The exponential trendline fits to the monthly averages, though useful for guiding the eye and showing long term trends, can hide changes such as network upgrades etc. which tend to happen in a stepwise fashion. To better visualize such major changes in performance we added the capability to average the data into yearly intervals. This is shown in Fig. 12 where the data is normalized as in Fig. 11 and there is one point/year. The lines simply are to assist the eye and are smoothed lines to join the points. By comparing with Fig. 9 it can be seen that there are several instances of step changes in performance not seen in Fig. 9. In particular note the improved performance as parts of Latin America moved from satellite to fibre in 2001, and the impact of the ESnet routing E. Asian (in particular Japanese academic and research networks) to the US via New York in 1999 and 2000.

Figure 12: Yearly averaged normalized derived TCP throughputs from the US to various regions of the world.

Variability of performance between and within regions  

The throughput results, so far presented in this report, have been measured from North America or to a lesser extent from Europe. This is partially since there is more data for a longer period available for the North America monitoring hosts. Table 4 shows the throughputs seen between monitoring and remote/monitored hosts in the major regions of the world. Each column is for monitoring hosts in a given region, each row is for monitored hosts in a given region. The cells are colored according to the median quality for the monitoring region/monitored region pair. White is for derived throughputs > 5000 kbits/s (good), blue for <= 5000 kbits/s and >1000kbits/s (acceptable), yellow for <= 100kbits/s and > 500 kbits/s, orange for <= 500kbits/s (very poor to bad), and magenta for no measurements. The table is column ordered by decreasing median performance. The Monitoring countries are identified by the Internet two-character Top Level Domain (TLD). Just for the record CH=Switzerland, DE=Denmark, HU=Hungary, CA=Canada, RU=Russia, JP=Japan, BR=Brazil, BO=Bolivia, IN=India, PK=Pakistan and ZA=South Africa. S. Asia is the Indian sub-continent; S.E. Asia is composed of measurements to Indonesia, Malaysia, Singapore, Thailand and Vietnam

Table 4: Derived throughputs in kbits/s from monitoring hosts to monitored hosts by region of the world for December 2006

As expected it can be seen that within regions (the circled cells) performance is generally better than between regions. Also performance is better between closely located regions such as Europe and S. E. Europe, Russia and E. Asia (the Russian monitoring site is in Novosibirsk)..  

To provide further insight into the variability in performance for various regions of the world seen from SLAC Fig. 13 shows various statistical measures of the losses and derived throughputs. The regions are sorted by the median of the measurement type displayed. Note the throughput graph uses a log y-scale to enable one to see the regions with poor throughput.  The countries comprising a region can be seen in Fig. 2.

Figure 13: 25 percentile, median and 75 percentile derived throughputs and losses for various regions measured from SLAC for Oct-Dec '05

The difference in throughput for N. America and Europe is an artifact of the measurements being made from N. America (SLAC) which has a much shorter RTT (roughly between a factor of  2 and 20 times or for the average sites close to 3 to 4) to N. American than to European sites. Since the derived throughput goes as 1/RTT  this favors N. America by about a factor of 3 to 4 times. The most uniform region (in terms of Inter-Quartile-Range/median for both derived throughput and loss) is Central Asia, probably since all the paths use a geo-stationary satellite.  The most diverse are N. America and Europe. For Europe, Belorussia stands out with poor performance. Hopefully the Porta-Optica project ( will improve this situation.  

Comparisons with Economic and Development Indicators

Various economic indicators have been developed by the U.N. and the International Telecommunications Union (ITU). It is interesting to see how well the PingER performance indicators correlate with the economic indicators. The comparisons are particularly interesting in cases where the agreement is poor, and may point to some interesting anomalies or suspect data. Also given the difficulty of developing the human and technical indicators (at best they are updated once a year and usually much less frequently), having indicators such as PingER that are constantly and automatically updated is a useful complement.

One such Index that covers many countries and is reasonably up-to-date is the UNDP Human Development Indicator ((see ). This is a summary measure of human development). It measures the average achievements in a country in three basic dimensions of human development:

·         A long and healthy life, as measured by life expectancy at birth

·         Knowledge, as measured by the adult literacy rate (with two-thirds weight) and the combined primary, secondary and tertiary gross enrolment ratio (with one-third weight)

·         A decent standard of living, as measured by GDP per capita (PPP US$).

Fig. 14 shows a scatter plot of the HDI versus the PingER Derived Throughput for July 2006. Each point is colored according to the country’s region. A logarithmic fit is also shown. Logarithmic is probably appropriate since Internet performance is increasing exponentially in time and the differences between the countries can be related to number of years they are behind the developing countries, while human development is more linear. Since the PingER Derived TCP Throughput is linearly proportional to RTT, countries close to the U.S. (i.e. the U.S., Canada and Central America) may be expected to have elevated throughputs compared to their HDI. We thus do not plot or use these countries in the correlation fit between HDI and throughput. It is seen that there is a strong correlation (R2 > 0.6) between the HDI and throughput. As expected countries in Africa generally occupy the lower values in x and y, and European countries together with Australia, New Zealand, Korea and Japan occupy the higher values of x and y.

Figure 14: Comparison of PingER derived throughputs seen from N. America to various countries and regions versus the U.N. Development Programme (UNDP) Human Development Indicator (HDI).

The Network Readiness Index (NRI) from the Center for International Development, Harvard University (see ) is a major international assessment of countries’ capacity to exploit the opportunities offered by Information and Communications Technologies (ICTs), i.e. a community’s potential to participate in the Networked World of the future. The goal is to construct a network use component that measures the extent of current network connectivity, and an enabling factors component that measures a country’s capacity to exploit existing networks and create new ones. Network use is defined by 5 variables related to the quantity and quality of ICT use. Enabling factors are based on Network access, network policy, networked society and the networked economy.

Figure 15: PingER throughputs measured from N. America vs. the Network Readiness Index.

Some of the outlying countries are identified by name. Countries at the bottom right of the right hand graph may be concentrating on Internet access for all, while countries in the upper right may be focusing on excellent academic & research networks.

The Digital Access Index (DAI) created by the ITU combines eight variables, covering five areas, to provide an overall country score. The areas are availability of infrastructure, affordability of access, educational level, quality of ICT services, and Internet usage. The results of the Index point to potential stumbling blocks in ICT adoption and can help countries identify their relative strengths and weaknesses.

Figure 16: PingER derived throughput vs. the ITU Digital Access Index for PingER countries monitored from the U.S.

Since the PingER Derived Throughput is linearly proportional to RTT, countries close to the U.S. (i.e. the U.S., Canada and Mexico) may be expected to have elevated Derived Throughputs compared to their DAI. We thus do not use the U.S. and Canada in the correlation fit, and they are also off-scale in Fig. 16. Mexico is included in the fit, however it is also seen to have an elevated Derived Throughput. Less easy to explain is India's elevated Derived Throughput. This maybe due to the fact that we monitor university and research sites which may have much better connectivity than India in general. Belarus on the other hand apparently has poorer Derived Throughput than would be expected from its DAI. This could be an anomaly for the one host currently monitored in Belarus and thus illustrates the need to monitor multiple sites in a developing country.

The United Nations Development Programme (UNDP) introduced the Technology Achievement Index (TAI) to reflects a country's capacity to participate in the technological innovations of the network age. The TAI aims to capture how well a country is creating and diffusing technology and building a human skill base. It includes the following dimensions: Creation of technology (e.g. patents, royalty receipts); diffusion of recent innovations (Internet hosts/capita, high & medium tech exports as share of all exports); Diffusion of old innovations (log phones/capita, log of electric consumption/capita); Human skills (mean years of schooling, gross enrollment in tertiary level in science, math & engineering). Fig. 17 shows December 2003's derived throughput measured from the U.S. vs. the TAI. The correlation is seen to be positive and medium to good. The US and Canada are excluded since the losses are not accurately measurable by PingER and the RTT is small. Hosts in well connected countries such as Finland, Sweden, Japan also have their losses poorly measured by PingER and  since they have long RTTs the derived throughput is likely to be low using the Mathis formula and if no packets are lost then assuming a loss of 0.5 packets in the 14,400 sent to a host in a month.

Figure 17: PingER derived throughputs vs. the UNDP Technology Achievement Index (TAI)

Case Study on NIIT, Pakistan

With NIIT being an important collaborator with SLAC, Caltech and CERN, we prepared a small case study with 3 PingER monitoring sites in Pakistan to provide a brief overview and a measure of the issues at NIIT in particular and Pakistan in general.

The Pakistan Education and Research Network (PERN) is a nationwide educational intranet connecting premiere educational and research institutions of the country. PERN focuses on collaborative research, knowledge sharing, resource sharing, and distance learning by connecting people through the use of Intranet and Internet resources”.

PERN uses the services of NTC (National Telecommunication Corporation), which is the national telecommunication carrier for all official/government services in Pakistan, for the provision of infrastructure and bandwidth to the universities in Pakistan. The PingER project worked with NTC install a PingER monitoring site at NTC headquarters in Islamabad, to monitor the performance of various universities connected to PERN. This data was compared with that from two PingER monitoring hosts at NIIT. One of the hosts uses NTC/PERN to provide external connectivity at 1-1.5Mbits/s, the second uses Micronet, a commercial network with a 512kbits/s connection to NIIT. We analyzed the data to compare the results from the three monitoring hosts to a common set of  sites in Pakistan, for seven weeks, from 7th Dec 2005 thru 28th Jan 06. All the sites were connected to PERN/NTC and information about them is provided in Table 5.


Table 5: Remote sites in Pakistan monitored from NIIT


Remote Node

University Location

Service Provider

Traffic Enters the Country Via

End host location

















































The minimum RTT from NTC is about 5ms versus about 10-12 ms from NIIT via NTC/PERN. Presumably the extra ~5 ms is a last mile effect. From NIIT via Micronet the minimum RTT is closer to 60ms. This may be partially due to slower backbone links (it takes longer to clock the packets onto the network links) and different routes. Unfortunately we are currently unable to make traceroute measurements from the NTC host.  

Looking at the average RTT results seen in Fig.18, there is a lot of variability, typically ranging from 150-400ms for the NIIT NTC/PERN host and 80-180ms for the NIIT Micronet host, and the data points for each remote host track one another closely. This indicates a common point of congestion. The NTC host results are fairly flat for each remote host, thus indicating little congestion. One can also see that the performance to the NIIT NTC/PERN connected host from NTC and from NIIT via Micronet is more variable and poorer than for the other Pakistani sites. This would appear to indicate that the congestion is located close to or at the NIIT site.

Figure 18: Average RTT from three hosts in Rawalpindi to Pakistani sites

The loss results shown in Fig.19 indicate that NTC has a low loss network with the packet loss percentage being less than 1% from the NTC monitoring host to the Pakistan university sites. The NIIT Micronet link though having less bandwidth and a higher minimum RTT is found to have roughly a factor five lower packet loss (1-2%) than the NIIT NTC/PERN link (5-10%). This is believed to be since the NTC/PERN link is used by default for all NIIT’s traffic with Micronet being reserved for a few select projects/faculty. The drop in loss during the Eids holidays (red circle), for the NTC/PERN link when students typically are not present, confirms this. The missing NIIT measurements around Eids (red ellipse) are due to a power outage at NIIT.


Figure19: Median packet loss from 3 hosts in Rawalpindi to Pakistani sites

We also prepared a case study on the internet outage in Pakistan during the month of July-05 [pak-fibre] which disconnected the only submarine fibre link (SEAMEW3) for the whole nation of 150 Million for almost a fortnight. Officials of the Internet Service Provider Association of Pakistan (ISPAK) said “the entire country was facing an Internet blackout after a problem occurred at the end of the only Internet backbone provider – PTCL”. The backup satellite links were inadequate to handle the country’s internet traffic. As a result many sites had no international Internet access at all and the few lucky ones (priority was given to call centers) experienced high packet loss and unacceptable performance. There have been several such extended fibre outage incidents (March, June-July, September) in the last year.

Conclusions for Pakistan

It appears that the NTC has an un-congested infrastructure and the minimum RTT from NTC to the PERN connected institutes is good. Adding another hop, the minimum RTT from NIIT being slightly higher is also understandable. However, the minimum RTT for the Micronet link suggests that the traffic, even if going to the same city adds around 45-50 ms to the RTT value as the service provider changes from NTC to Micronet. It also appears that the NIIT default link via NTC/PERN is heavily congested. Recent attempts to upgrade the link from 1 to 1.5Mbits/s have met with limited success.

International connectivity for Pakistan is extremely fragile with inadequate backup for the only fibre link.  With focus of the existing government on the development of telecommunications infrastructure in the country [pak-develop-news], efforts are being made in this direction and once the SEAMEWE4 cable is active, the international bandwidth available to the country should get a huge boost. Another area that needs to be taken care of, especially for NIIT, is the power problem, and efforts need to be made to ensure that machines are up 24/7. Proper power backup mechanisms need to be designed for better and more effective collaborative initiatives with the international community and better learning environment for the people within.

It is encouraging to know that NTC and Micronet appear to provide good backbone Internet services in Pakistan. However, with the increasing usage especially in the academic institutes, initiatives for even more rapid development are required. PERN has been fairly active in upgrading its infrastructure. Efforts to shift from copper to fiber over the last mile are underway [Pernprop], however, in order to catch up with the rest of the world, the pace of development needs to be more aggressive.

Africa and South Asia: Comparison between Min and Avg. RTTs

In Fig. 20, the main influence on the min-RTT (blue bar) should be the physical distance between the monitor and the monitored site. Min-RTTs of over 600ms usually indicate that a geo-stationary satellite link is in use. The shortest min RTTs (the red ellipses) are expected to be between hosts that are in the same country (e.g. an Indian host monitoring another Indian host). The difference in the min-RTT and avg-RTT (the red bars) is an indication of queuing delays or congestion.

It is seen that all sites monitored from Pakistan have significant congestion (> 150 ms). For this period we were only making measurements from the NIIT/NTC host/link which is heavily congested. If we take January 2006, when we had data from  NIIT/NTC, NIIT/Micronet and NTC hosts, then the minima are respectively 11s and 57ms and 5ms, and the averages 231ms and 114 ms and 49ms. So the measurements from Pakistan to Pakistan for Oct-Dec are misleading. It also turns out that the Pakistan measurements from Africa are only to the congested NIIT/NTC host/link. India measures to NIIT/NTC and also to NIIT/Micronet. The min-RTTs are similar (250ms for Micronet vs. 300ms for NIIT), however the average RTTs from India to NIIT/NTC (707ms) are roughly double those to Micronet (341ms). We have recently increased the number of Pakistani hosts monitored from S. Africa which should help avoid the NIIT/NTC anomaly.

For within country paths between monitoring and monitored sites, India is a larger country than Pakistan and thus, excluding the NIIT/NTC measurements, has longer minimum RTTs. However, the difference in average – minimum RTT is lower for India (20ms) than for Pakistan (40-50ms) even if one excludes the NIIT/NTC measurements.

Even though Botswana is adjacent to S. Africa (and thus has low min-RTT), it is seen that the path is heavily congested (over 400ms.). Other countries with heavy congestion seen from S. Africa are Argentina, Madagascar, Ghana and Burkina Faso.



Figure 20: Congestion seen from Africa, India and Pakistan to the different countries; Measurements for Oct-Dec 2005 of min-RTT and average RTT from India, Pakistan and S. Africa to various countries; Countries with monitored hosts common to all monitoring countries are shown in yellow.

Case Study for Africa

In August 05, with assistance from TENET, we deployed a monitoring node in South Africa to get a view of Africa from within Africa.  In Nov 2006 we made a case study on the end-to-end network connectivity of the Sub-Sahara region of Africa. Many parts of this region suffer from severe disadvantages including lack of electricity, skills, disease, protectionist policies and corruption. At the same time Africa has almost three times lower percentage of population using the Internet (3.6% [worldstats]) compared to any other world region. However, Africa has a huge potential, containing 14% of the world population, and its use of the Internet is growing more rapidly than any other region of the world (626% between 2000 and 2006). For more on Africa see Connectivity Mapping in Africa [ictp-jensen], African Internet Connectivity [africa] and Internet Performance to Africa [ejds-africa]).

The study was presented by Dr. Les Cottrell at Sharing Knowledge Across the Mediterranean Conference at ICTP Trieste, Italy in Nov 2006. First we looked at the traceroutes to these remote sites in African countries from South Africa. We summarize our results in Fig 21.

Figure 21: Routing to various countries in Africa. This data is typically based on 2 or 3 nodes per country

The data is typically based on 2 or 3 nodes per country. The initial analysis shows that the various countries in Africa have fairly diverse routing that is seldom very direct. A majority of the traffic going from South Africa to these countries goes via Europe or North America. Only Botswana and Zimbabwe have direct routing from South Africa. To Burkina Faso, the traffic first goes to Europe from South Africa, then USA and finally in to the country. Since international bandwidth prices are typically the biggest contributor to costs, African users are effectively subsidizing international transit providers. Unfortunately fibre optic links are few and expensive so there is still a high reliance on satellite connectivity with high round trip latencies, slow speeds and high prices. All this inhibits the growth of Internet businesses. One development that would help would be the creation of more African regional or national International eXchange Points (IXPs) that interconnect directly to the other IXPs in Africa. In 2003, 10 out of 53 African countries had IXPs, and in 2006 it had risen to 16. These should lead to lower latencies, lower costs[3] and increased usage.

Next we looked at the minimum RTTs to determine satellite usage.  Fig. 22 on the left shows the minimum RTTs measured from S. Africa to sites in other African countries, and on the right the current distribution of fibre links.

Figure 22: On the left are shown the minimum RTTs from S. Africa to African countries, and on the right are the current fibre links for Africa.

There is currently only one intercontinental fibre link to Sub-Saharan Africa (SAT-3) which provides connections to Europe and the Far East for eight countries along the West Coast of the Continent. Except for some onward links from South Africa to its neighbors, and from Sudan to Egypt and from Senegal to Mali, the remaining 33 African countries are unconnected to the global optical backbones, and depend on the much more limited and high-cost bandwidth from satellite links[4]. Even the few countries that have access to international fibre through SAT-3 are not seeing the benefits because it is operated as a consortium where connections are charged at monopoly prices by the state owned operators which still predominate in most of Africa, and in many other developing regions.

The East Africa Submarine Cable System (EASSy [EASSy]) Project is an initiative to connect countries of East Africa via fibre. It is planned to run from S. Africa to Sudan with landing points in six countries and connections to at least five landlocked countries and to be operation by the fourth quarter of 2007. The partners include Botswana, Burundi, Djibouti, Ethiopia, Kenya, Madagascar, Mozambique, Rwanda, Somalia, South Africa, Sudan, Zanzibar, Tanzania and Uganda so this could make a big improvement for this area. This cable will also link Northern and Southern African international gateways to the system. Still to be resolved issues of access make it unclear whether this will suffer from the monopolization issues that have plagued SAT-3 or whether the access will be more open and lead to dramatically improved cost/performance.   Fig. 23 shows plans for African connectivity including EASSy.

Figure 23: Medium Term Plans for African Connectivity

Looking at derived throughput, seen in Fig 24 it is seen that there are enormous differences between and within regions with over a factor of 30 difference between say Eritrea and Morocco. As might be expected, given its proximity to and strong ties with Europe, N. African countries typically have the best performance, followed by W. Africa, with E. Africa and Central Africa having the poorest performance.

Figure 24: Derived throughput from the US to Africa.

The longer term throughput trends for Africa are shown in Fig. 25 where the straight lines are exponential fits to the data, and the jagged lines join the individual points that are the monthly averages for all the sites in each region. The data covers 87 sites in 32 countries. It can be seen that apart from S Africa there is very little improvement and E. Africa has consistently the poorest performance.

Figure 25: Derived TCP throughput trends from the US to African regions

While analyzing the data for individual countries we observed some interesting trends as well. For instance Sudan shifted from a minimum RTT of approx. 685 ms to approx. 260 ms in Nov 2004, Botswana shifted from 600+ ms to 350 ms in Sep 2004, and Ghana shifted from 650ms to 450ms in Sep 2006. These are all classic cases of shifts from satellite to fiber. A more detailed version of the case study for the individual countries with accompanying charts, topology maps and analysis is available at ( ).

We also compared the throughputs for Africa, the Middle East and Europe with the UNDP HDI (see above). The results are seen in Fig. 26 where the dot sizes are proportional to the country’s population. It is seen that there is a strong correlation. N. Africa has 10 times poorer performance than Europe. Croatia has 13 times better performance than Albania.. Israel has 8 times better performance than rest of the Middle East. Once again the great diversity within (e.g. Senegal has over ten times the performance of Ghana) and between African regions (North Africa countries typically have a factor of ten performance better than East African countries) stands out.

Figure 26: Correlation plot between the UNDP HDI and the median average monthly derived TCP throughput (from Jan. through Sep. 2005) for Africa, Mediterranean Europe and the Middle East

High Performance Network Monitoring

IEPM-BW Results

The PingER method of measuring throughput breaks down for high speed networks due to the different nature of packet loss for ping compared to TCP, and also since PingER only measures about 14,400 pings of a given size/month between a given monitoring host/monitored host pair. Thus if the link has a loss rate of better than 1/14400 the loss measurements will be inaccurate. For a 100Byte packet, this is equivalent to a Bit Error Rate (BER) of 1 in 108, and leading networks are typically better than this today (Jan 2006). For example if the loss probability is < 1/14400 then we take the loss as being 0.5 packet to avoid a division by zero, so if the average RTT for ESnet is 50msec then the maximum throughput we can use PingER data to predict is ~ 1460Bytes*8bits/(0.050sec*sqrt(0.5/14400)) or ~ 40Mbits/s and for an RTT of 200ms this reduces to 10Mbits/s.

To address this challenge and to understand and provide monitoring of high performance throughput between major sites of interest to HEP and the Grid, we developed the IEPM-BW monitoring infrastructure and toolkit. There are about 5 major monitoring hosts and about 50 monitored hosts in 9 countries (CA, CH, CZ, FR, IT, JP, NL, UK, US). Both application (file copy and file transfer), TCP throughputs, available bandwidth, RTT, losses and traceroutes are measured.

These measurements indicate that throughputs of several hundreds of Mbits/s are regularly achievable on today's production academic and research networks, using common off the shelf hardware, standard network drivers, TCP stacks etc., standard packet sizes etc. Achieving these levels of throughput requires care in choosing the right configuration parameters. These include large TCP buffers and windows, multiple parallel streams, sufficiently powerful cpus (typically better than 1 GHz), fast enough interfaces and busses, and a fast enough link (> 100Mbits/s) to the Internet. In addition for file operations one needs well designed/configured disk and file sub-systems.

Though not strictly monitoring, there is currently much activity in understanding and improving the TCP stacks (e.g. [floyd], [low], [ravot]). In particular with high speed links (> 500Mbits/s) and long RTTs (e.g. trans-continental or trans-oceanic) today's standard TCP stacks respond poorly to congestion (back off too quickly and recover too slowly). To partially overcome this one can use multiple streams or in a few special cases large (>> 1500Bytes) packets. In addition new applications ([bbcp], [bbftp], [gridftp]) are being developed to allow use of larger windows and multiple streams as well as non TCP strategies ([tsnami], [udt]). Also there is work to understand how to improve the operating system configurations [os] to improve the throughput performance. As it becomes increasingly possible to utilize more of the available bandwidth, more attention will need to be paid to fairness and the impact on other users (see for example [coccetti] and [bullot]). Besides ensuring the fairness of TCP itself, we may need to deploy and use quality of service techniques such as QBSS [qbss] or TCP stacks that back-off prematurely hence enabling others to utilize the available bandwidth better [kuzmanovic]. These subjects will be covered in more detail in the companion ICFA-SCIC Advanced Technologies Report. We note here that monitoring infrastructures such as IEPM-BW can be effectively used to measure and compare the performance of TCP stacks, measurement tools, applications and sub-components such as disk and file systems and operating systems in a real world environment.

New Monitoring and Diagnostic Efforts in HEP

PingER and IEPM-BW are excellent systems for monitoring the general health and capability of the existing networks used worldwide in HEP. However, we need additional end-to-end tools to provide individuals with the capability to quantify their network connectivity along specific paths in the network and also easier to use top level navigation/drill-down tools. The former are needed to both ascertain the user's current network capability as well as to identify limitations which may be impeding the user’s ultimate (expected) network performance. The latter are needed to simplify finding the relevant data.

Most HEP users are not "network wizards" and don't wish to become one. In fact as pointed out by Mathis and illustrated in Fig. 27, the gap in throughput between what a network wizard and a typical user can achieve is growing.

Figure 27: Bandwidth achievable by a network wizard and a typical user as a function of time. Also shown are some recent network throughput achievements in the HEP community.

Because of HEP's critical dependence upon networks to enable their global collaborations and grid computing environments, it is extremely important that more user specific tools be developed to support these physicists.

Efforts are underway in the HEP community, in conjunction with the Internet2 End-to-End (E2E) Performance Initiative [E2Epi], to develop and deploy a network measurement and diagnostic infrastructure which includes end hosts as test points along end-to-end paths in the network. The E2E piPEs project [PiPES], the NLANR/DAST Advisor project [Advisor] and the LISA (Localhost Information Service Agent) [LISA] are all working together to help develop an infrastructure capable of making on demand or scheduled measurements along specific network paths and storing test results and host details for future reference in a common data architecture. The information format will utilize the GGF NMWG [NMWG] schema to provide portability for the results. This information could be immediately used to identify common problems and provide solutions as well as to acquire a body of results useful for baselining various combinations of hardware, firmware and software to define expectations for end users.

A primary goal is to provide as "lightweight" a client component as possible to enable widespread deployment of such a system. The LISA Java Web Start client is one example of such a client, and another is the Network Diagnostic Tester (NDT) tool [NDT]. By using Java and Java Web Start, the most current testing client can be provided to end users as easily as opening a web page. The current version supports both Linux and Windows clients.

Details of how the data is collected, stored, discovered and queried are being worked out. A demonstration of a preliminary system was shown at the Internet2 Joint-techs meeting in Hawaii on January 25th, 2004.

The goal of easier to use top level drill down navigation to the measurement data is being tackled by MonALISA [MonALISA] in collaboration with the IEPM project.

LHC-OPN Monitoring

During the last year there has been a concerted effort to deploy and monitor the central data distribution network for the Large Hadron Collider (LHC).  This network, dubbed the LHC-OPN (Optical Private Network), is being created to primarily support  the data distribution from the CERN Tier-0 to the various Tier-1’s worldwide.  In addition, traffic between Tier-1 sites is also allowed to traverse the OPN. 

Given the central role this network will play in the distribution of data it is critical that this network and its performance be well monitored.  A working group was convened in Fall of 2005 to study what type of monitoring might be appropriate for this network.  A number of possible solutions were examined including MonALISA, IEPM-BW/Pinger, various EGEE working group efforts and perfSONAR. 

By Spring of 2006 there was a consensus that LHC-OPN monitoring should build upon the perfSONAR effort which was already being deployed in some of the most important research networks. perfSONAR is a standardized framework for capturing and sharing monitoring information, other monitoring systems can be plugged into it with some interface “glue”.

Related HEP Network Research 

There is also a significant amount of research around managed networks for HEP that is ongoing.  There are efforts funded by the National Science Foundation (UltraLight) and Department of Energy (Terapaths, LambdaStation and OSCARS) which are strongly based in HEP.  These projects are not primarily focused upon monitoring but all have aspects of their efforts that do provide network information applications.  Some of the existing monitoring discussed in previous sections are either came out of these efforts or are being further developed by them.

Comparison with HEP Needs

Recent studies of HEP needs, for example the TAN Report ( have focused on communications between developed regions such as Europe and North America.  In such reports packet loss less than 1%, vital for unimpeded interactive log-in, is assumed and attention is focused on bandwidth needs and the impact of low, but non-zero, packet loss on the ability to exploit high-bandwidth links.  The PingER results show clearly that much of the world suffers packet loss impeding even very basic participation in HEP experiments and points to the need for urgent action.

The PingER throughput predictions based on the Mathis formula assume that throughput is mainly limited by packet loss.  The 40% per year growth curve in Fig. 10 is somewhat lower than the 79% per year growth in future needs that can be inferred from the tables in the TAN Report. True throughput measurements have not been in place for long enough to measure a growth trend.  Nevertheless, the throughput measurements, and the trends in predicted throughput, indicate that current attention to HEP needs between developed regions could result in needs being met.  In contrast, the measurements indicate that the throughput to less developed regions is likely to continue to be well below that needed for full participation in future experiments.

Accomplishments since last report

We have extended the measurements to cover more developing countries and to increase the number of hosts monitored in each developing country. We have carefully evaluated the routes and minimum ping RTTs to verify that hosts are where they are identified to be in our database. As a result we have worked with contacts in relevant countries and sites to find alternatives, and about 20-30 hosts have been replaced by more appropriate hosts. In addition (see Table 6) we have added over 120 new remote hosts, and added 10 new countries (AO, CY, LB, NL, PS, SI, ES, SY, VN, and ZM). At the same time in the last year we are no longer able to find hosts to monitor in 3 countries (BG, CO, SB), in the previous year we lost 10 countries (AU, BE, KY, MO, RE, SA, SC, SL, ES and VN), but recovered one last year (VN). The unreachability of these sites has mainly been caused by ping blocking.

The collaboration between SLAC and the NIIT in Rawalpindi Pakistan was funded by the Pakistan Ministry of Science and Technology and the US Department of State for one year starting September 2004. The funding is for travel only. The collaboration has successfully developed and populated a new PingER configuration database to keep track of location (city, country, region, latitude/longitude), contacts, site name, affinity groups etc. This data is already being used to provide online maps such as Fig. 1. Work has also been completed on automating the process of generating graphs of performance aggregated by region

We still spend much time working with contacts to unblock pings to their sites (for example ~15% of hosts pingable in July 2003 were no longer pingable in December 2003), to identify the locations of hosts and to find new hosts/sites to monitor. It is unclear how cost-effective this activity is. It can take many emails to explain the situation, sometimes requiring restarting when the problem is passed to a more technically knowledgeable person. Even then there are several unsuccessful cases where even after many months of emails and the best of intentions the pings remain blocked. One specific case was for all university sites in Vietnam were blocked for ping.  We have been working with James Whitlock of the Bethlehem Alliance Project people for several months to get sites to monitor, however the fragile political situation has delayed fruition.

Even finding knowledgeable contacts, explaining what is needed and following up to see if the recommended hosts are pingable, is quite labor intensive. To assist with this we have created a brochure for PingER describing its purposes, goals and requirements. More recently we have had some success by using Google to search for university web sites in specific TLDs and this year have automated this. The downside is that this way we do not have any contacts with specific people with whom we can deal in case of problems.

Efforts to Improve PingER Management

With the increase in the monitoring data of PingER, we initiated efforts to develop supporting systems for better management and installation of PingER. In all, several major initiatives have been taken, which are summarized below:

TULIP- IP Locator Using Triangulation

With the growth in the coverage of PingER arises the great difficulty of keeping track of the changes in the physical locations of the monitored sites. This might lead to mis-leading conclusions, for instance our sole monitoring node in Sweden had a minimum RTT of 59ms from SLAC. This is not possible as a node deployed at the East Coast in USA has a minimum RTT value greater than 70 ms.  Moreover, many nodes in the developing region often change their geographical locations for a variety of reasons. In order to detect and track changes in the physical locations of nodes, the PingER team launched a task to build a tool to give the latitude and longitude for a given IP address or URL. This tool will then be used to identify hosts whose located position is in conflict with the PingER database latitude and longitude by comparing the minimum RTT with that predicted from distance between the monitor and remote sites and making traceroute measurements to further vindicate the results. Anomalies will be reported so the PingER database can be corrected using values from the locator tool and/or new hosts can be chosen to be monitored.

The location of an IP address is being determined using the minimum RTT measured from multiple “landmark” sites at known locations, and triangulating the results to obtain an approximate location. The basic application, prototype deployed at is a java based jnlp application that takes RTT measurements from landmarks to a selected target host (typically at an unknown location) specified by the user and figures out the latitudes and longitudes of the target host. The application is under-development and its algorithm and the provision of landmark sites under constant improvement to make the process reasonably accurate.

TULIP (IP Locator Using Triangulation) will also utilize the historical min-RTT PingER data in order to verify the locations of hosts/sites recorded in the PingER configuration database, and to optimize the choices of parameters used by TULIP.

PingER Host Searching Tool

Increasing the coverage of PingER in developing countries has been difficult historically because it is hard to find hosts which are geographically located within those countries and do not block pings. PingER host searching tool is an attempt to solve this problem. It completely automates the process of searching for hosts for monitoring within a country by doing the following:

1.      It downloads the search results for the required country from Google using its TLD(Top Level Domain).

2.      Using regular expressions and pattern matching it searches for hostnames in the results.

3.      After compiling a list of unique hostnames, it pings each hostname in turn and filters out those which block pings.

4.      Finally it checks the hosts in the filtered list on GeoIptool (, further sorting out the hosts which are not geographically located in the target country. It was found that Geoiptool geo-locates hosts with a high degree of accuracy.

5.      After going thorough the above steps the tool reports the final filtered list of hosts which are candidates for monitoring in the required country.

It was very helpful in improving the coverage of PingER in Africa where we now have 91 monitored hosts in 35 countries. It is also being used to improve coverage in South America.

PingER Validation Toolkit

Since its inception, the size of the PingER project has grown to where it is now monitoring hosts in over 120 countries from about 35 monitoring hosts in 14 countries. With growth in the number of monitoring as well as monitored (remote) nodes, it was perceived that automated mechanisms need to be developed for managing this project. We therefore developed a tool that runs daily and reports on the following:

·        Database errors such as invalid or missing IP addresses, all hosts have an associated region, each host only appears once in the database, all hosts have a latitude and longitude, the names of the monitoring hosts match the labeling of the data gathered from the monitoring host, each host has a unique IP address.

·        The list of beacons are now generated from the database, as is the list of sites to be monitored
·        We ping all hosts, those not responding are tested to see if the exist (i.e. they do not repond to a name service request), whether they respond to any of the common TCP ports, if so they are marked as blocking pings. If they do not ping with the IP address we try the name in case the IP address has changed.
·        We track how long a host pair (monitor host/remote host) has not successfully pinged and whether the remote host is blocked.
·        We keep track of how long we have been unable to gather data from each monitoring host.
·         We also compare the minimum RTT for sites within a region with one another and look to see whether any are outside 3-4 standard deviations. This is designed to help find hosts that are not really located in a region (e.g. a proxied elsewhere). 

PingER Executive Plots

As PingER grew in coverage and scope, a need was felt for software to provide a coherent way of quickly analyzing the trends in the data. PingER Executive Plots is a set of tools aimed at seamlessly integrating a high-level graphical analysis front-end to the raw data being generated. It was developed in Java as a jnlp application and can be run anywhere in the world over the web.

The two main analysis capabilities provided by this suite are:

1.      High-level trend analysis of data for metrics like TCP Throughput, Packet Loss, Min/Avg RTT etc for various regions from all PingER monitoring sites.

2.      Cumulative quality graphs showing breakup of sites with a particular loss quality within a region.

These analysis capabilities are supplemented by a wide-variety of features that make it a useful tool, including:

1.      It allows the user to dynamically download the current data available in the SLAC archives, over the web, for graphing. This means that as soon as the latest data is updated at the SLAC archives, it is available for analysis anywhere.

2.      Other features include:

a.       Ability to select logarithmic or exponential views of the trendlines.

b.      Zoom in/out on a particular time-interval.

c.       Adding/removing the lines/points corresponding to specific countries/regions.

d.      Dynamic tooltips on the entire chart area displaying information about specific datapoints.

e.       Saving a snapshot of the graphs as image files.

f.        Viewing and storing the goodness of fit parameters for trendlines in a file.

3.      The cumulative quality graphs application enables the user to form their own query consisting of a specific monitoring site, remote region and metric for graphing.

Fig. 28 shows a screen snapshot of exponential trendlines from SLAC to various regions (labeled continent) of the world together with the data points for two of the lines.

Figure 28: Snapshot of PingER Executive Plots in action

ViPER (Visualization for PingER)

With the wide deployment of PingER, ViPER provides an extremely valuable, eye-catching, overview of PingER's deployment and the performance between various regions of the world. Since PingER is focusing on mapping the Digital Divide, it desperately needs simple to use, graphically engaging tools such as ViPER to grab the attention of politicians, executives and upper management at funding agencies, and NGOs. ViPER also is valuable to the management of PingER since it quickly identifies PingER database errors (e.g. hosts with incorrect latitude/longitude) enabling better quality control.

ViPER has a user friendly interface that allows a user to perform interactive analysis on PingER data. It uses a world map to show the geographic location of all the PingER nodes. When the user selects a particular node, detailed information about that node is shown. Also the links are colored according to their performance so the user can compare the performance of various links.

The user can plot graphs of various metrics such as TCP throughput, minimum RTT and packet loss between a remote monitoring site pair. The graph will show the historical performance of the link. The user can save the analysis information for future reference.  A screen shot of ViPER is shown in Fig. 29.

Figure 29: Screen shot of ViPER showing the losses from CDAC India in Mumbai to CERN in Geneva Switzerland

At the bottom of the screen shot is shown the user selection for the monitoring site and remote site, and the metric, also shown on the map in red are the Monitoring sites and in green the remote sites. A colored line from the chosen monitoring site (CDAC in Mumbai) to the remote host (at CERN in Geneva) indicates the quality of the end-to-end path in terms of the chosen metric - loss (the legend of colors is given in the top right).  Moving the mouse over a site will pop up the name of the site or sites if there are multiple sites in the area. Clicking on the site will give detailed configuration information about the site(s). In the case of Fig. 29 the user has also requested to plot the losses for the last 60 days that is shown in the overlaid window.

ViPER is a Java application that has been deployed on JNLP (the Java Network Launching Protocol). Thus the application is launched through a simple mouse click and the users do not need to install the application. The application is deployed at

Digital Divide Publications/Presentations:

·         Bridging the Digital Divide, R. Les Cottrell and Harvey Newman, American Institute of Physics Forum on International Physics Newsletter.

·         Quantifying the Digital Divide: A Scientific Overview of the Connectivity of South Asian and African Countries, A. Rehmatullah, R. L. Cottrell, J. Williams, A. Ali, CHEP06.

·         January 2006 Report of the ICFA-SCIC Monitoring Working Group, edited by Les Cottrell for the ICFA SCIC Monitoring Working Group.

Talks (Most recent first)

·         Sub-Saharan Africa is a dark zone for World Internet: Sounding an Alarm, prepared by Les Cottrell, presented by Warren Matthews at the Internet2 Fall 2006 Members Meeting, Chicago Dec 2006

·         Sub-Saharan Africa is a dark zone for World Internet: Sounding an Alarm, presented by Les Cottrell at the Sharing Knowledge Across the Mediterranean conference at ICTP Trieste Nov 6-8, 2006.

·         Quantifying the Digital Divide from an Internet Point of View, R. Les Cottrell, Aziz Rehmatullah, Jerrod williams and Akbar Mehdi, Presented at the Reuters Digital Vision Program Stanford October 17, 2006.

·         Internet Monitoring and Results for the Digital Divide, R. Les Cottrell, Aziz Rehmatullah, Jerrod williams and Akbar Mehdi, presented at the "International ICFA Workshop on Grid Avtivities within Large Scale International Collaborations", Sinaia, Romania October 13-18, 2006.

·         Navigating PingER, R. Les Cottrell, presented at ICTP "Optimization Technologies for Low-Bandwidth Networks" workshop

·         Quantifying the Digital Divide from an Internet Point of View, R. Les Cottrell, Aziz Rehmatullah, Jerrod williams and Akbar Mehdi, presented at ICTP "Optimization Technologies for Low-Bandwidth Networks" workshop Trieste October 2006.

·         PingER: An Effort to Quantify the Digital Divide, presented by Aziz Rehmatullah, May 2006.

·         Stanford University, SLAC, NIIT, the Digital Divide and Bandwidth Challenge, Presented by Les Cottrell to the NUST/NIIT Faculty,Islamabad, Feb 2006.

·         Quantifying the Digital Divide: A scientific overview of the connectivity of South Asian and African Countries, presented by Les Cottrell at CHEP06.


There is interest from ICFA, ICTP and others to extend the monitoring further to countries with no formal HEP programs, but where there are needs to understand the Internet connectivity performance in order to aid the development of science. Africa is a region with many such countries. The idea is to provide performance within developing regions, between developing regions and between developing regions and developed regions.

We should ensure there are >=2 remote sites monitored in each Developing Country. All results should continue to be made available publicly via the web, and publicized to the HEP community and others. Typically HEP leads other sciences in its needs and developing an understanding and solutions. The outreach from HEP to other sciences is to be encouraged. The results should continue to be publicized widely.

We need assistance from ICFA and others to find sites to monitor and contacts in the following countries:

·         Latin America: Panama, Paraguay (need > 1 site/country), Columbia (have none)

·         Belarush (need > 1), Bulgaria, Moldova (have none)

·          Africa: Burundi, Cameroon, Mali, Mauritania, Niger, Zimbabwe (all need > 1 site/country), Democratic Republic of the Congo, Libya,  Somalia, (have none)

·         Mid East and Central Asia: Afghanistan, Kazakhstan, Jordan, Uzbekistan (need > 1 site/country), Iraq, Kyrgyzstan, Saudi Arabia (have none)

Although not a recommendation per se, it would be disingenous to finish without noting the following. SLAC & FNAL are the leaders in the PingER project. The funding for the PingER effort came from the DoE MICS office since 1997, however it terminated at the end of the September 2003, since it was being funded as research and the development is no longer regarded as a research project. To continue the effort at a minimum level (maintain data collection, explain needs, reopen connections, open firewall blocks, find replacement hosts, make limited special analyses and case studies, prepare & make presentations, respond to questions) would probably require central funding at a level of about 50% of a Full Time Equivalent (FTE) person, plus travel. Extending and enhancing the project, fixing known non-critical bugs, improving visualization, automating reports generated by hand today, finding new country site contacts, adding route histories and visualization, automate alarms, updating the web site for better navigation, adding more Developing Country monitoring sites/countries, improve code portability) interestingly is currently being addressed by the  MAGGIE-NS project with NIIT in Pakistan funded for one year by the US Department of State and the Pakistani Ministry Of Science and Technology (MOST). However this funding has terminated and NIIT and SLAC are supporting PingER without funding. Without funding, for the operational side, the future of PingER and reports such as this one is unclear, and the level of effort sustained in 2003 and 2004, 2005 and 2006 will not be possible in 2007. Many agencies/organizations have expressed interest (e.g DoE, ESnet, NSF, ICFA, ICTP, IDRC, UNESCO) in this work but none can (or are allowed to) fund it. A recent proposal to the U.S. Department of State was not funded. We will submit a new proposal later this year.

Appendix: Countries in PingER Database

Table 6 lists the 124 countries currently (January 1st 2006) in the PingER database.  The number in the column to the right of the country name is the number of hosts monitored in that country. The number cell is colored magenta for if we have monitored no hosts in that country for the last 2 years, orange where we used to monitor a host in the country last year but this year no longer monitor any hosts in the country, and yellow where we currently monitor only one host. Countries marked in green have been added in the last year. The smallest country we monitor in terms of population is French Polynesia followed by Iceland. The largest countries we do not monitor in terms of population are the Philippines, followed by Vietnam, the Democratic Republic of the Congo, Myanmar and Colombia.

Table 6: PingER countries monitored from SLAC with the number of sites/country. Countries in green were added in 2006. We are unable to find any monitorable sites any longer in countries with <=0 sites.


We gratefully acknowledge the following: the assistance from NUST/NIIT in improving the PingER toolkit and management has been critical to keeping the project running, with respect to this we particularly acknowledge the support of their leader Arshad Ali; Akbar Khan of NIIT helped in updating some of the graphs and the case study on Africa; Shawn McKee of the University of Michigan kindly provided the sections on LHC-OPN Monitoring and Related Network Research; Mike Jensen provided much useful information on the status of networking in Africa, Alberto Santaro of UERJ provided very useful information on Latin America; Sergio Novaes of UNESP and Julio Ibarra of Florida International University provided useful contacts in Latin America. We received much encouragement from Marco Zennaro and Enrique Canessa of ICTP and from the ICFA/SCIC in particular from Harvey Newman the chairman. We must also not forget the help and support from the administrators of the PingER monitoring sites worldwide


[africa] Mike Jensen, "African Internet Connectivity". Available
[africa-rtm] Enrique Canessa, "Real time network monitoring in Africa - A proposal - (Quantifying the Digital; Divide)". Available
[bbcp] Andrew Hanushevsky, Artem Trunov, and Les Cottrell, "P2P Data Copy Program bbcp", CHEP01, Beijing 2002. Available at
[bbftp] "Bbftp". Available
[bcr] “Application Demands Outrun Internet Improvements”, P. Sevcik, Business Communications Review, January 2006.

[bullot] "TCP Stacks Testbed", Hadrien Bullot and R. Les Cottrell. Avialble at
[cia-pop-figures] Available at:

[coccetti] "TCP STacks on Production Links", Fabrizzio Coccetti and R. Les Cottrell. Available at
[eassy] The East African Submarine System

[ejds-email] Hilda Cerdeira and the eJDS Team, ICTP/TWAS Donation Programme, "Internet Monitoring of Universities and Research Centers in Developing Countries". Available
[ejds-africa] "Internet Performance to Africa" R. Les Cottrell and Enrique Canessa, Developing Countries Access to Scientific Knowledge: Quantifying the Digital Divide, ICTP Trieste, October 2003; also SLAC-PUB-10188. Available 
[ejds-pinger] "PingER History and Methodology", R. Les Cottrell, Connie Logg and Jerrod Williams. Developing Countries Access to Scientific Knowledge: Quantifying the Digital Divide, ICTP Trieste, October 2003; also SLAC-PUB-10187. Available
[floyd] S. Floyd, "HighSpeed TCP for Large Congestion Windows", Internet draft draft-floyd-tcp-highspeed-01.txt, work in progress, 2002. Available
[gridftp] "The GridFTP Protocol Protocol and Software". Available
[host-req] "Requirements for WAN Hosts being Monitored", Les Cottrell and Tom Glanzman. Available at
[icfa-98] "May 1998 Report of the ICFA NTF Monitoring Working Group". Available
[icfa-mar02] "ICFA/SCIC meeting at CERN in March 2002". Available
[icfa-jan03] "January 2003 Report of the ICFA-SCIC Monitoring Working Group". Available

[icfa-jan04] "January 2004 Report of the ICFA-SCIC Monitoring Working Group". Available

[icfa-jan05] "January 2005 Report of the ICFA-SCIC Monitoring Working Group". Available

[icfa-jan06] "January 2006 Report of the ICFA-SCIC Monitoring Working Group". Available
[iepm] "Internet End-to-end Performance Monitoring - Bandwidth to the World Project". Available
[ictp] Developing Country Access to On-Line Scientific Publishing: Sustainable Alternatives, Round Table meeting held at ICTP Trieste, Oct 2002. Available
[ictp-jensen] Mike Jensen, "Connectivity Mapping in Africa", presentation at the ICTP Round Table on Developing Country Access to On-Line Scientific Publishing: Sustainable Alternatives at ITCP, Trieste, October 2002. Available
[ictp-rec] RECOMMDENDATIONS OF the Round Table held in Trieste to help bridge the digital divide. Available
[kuzmanovic] "HSTCP-LP: A Protocol for Low-Priority Bulk Data Transfer in High-Speed High-RTT Networks", Alexander Kuzmanovic, Edward Knightly and R. Les Cottrell. Available at


[low] S. Low, "Duality model of TCP/AQM + Stabilized Vegas". Available
[mathis] M. Mathis, J. Semke, J. Mahdavi, T. Ott, "The Macroscopic Behavior of the TCP Congestion Avoidance Algorithm",Computer Communication Review, volume 27, number 3, pp. 67-82, July 1997
[nua] NUA Internet Surveys, "How many Online". Available
[os] "TCP Tuning Guide". Available

[pak-develop-news] News Article entitled “PM launches Seamewe-4 submarine cable” Available at
[pak-fibre] “Fiber Outage in Pakistan June 27th 2005 to July 8th 2005”, R. L. Cottrell, A. Rehmatullah, available at

[pinger] "PingER". Available; W. Matthews and R. L. Cottrell, "The PingER Project: Active Internet Performance Monitoring for the HEP Community", IEEE Communications Magazine Vol. 38 No. 5 pp 130-136, May 2002.

[perfSONAR] PERFormance Service Oriented Network monitoring Architecture , see

[Pernprop] PC-1 Documents: 1) “Last Mile Pakistan Education and Research Network Connectivity Model PC-1” and 2 ) “Conversion of last mile Pakistan Education and Research Network Connectivity to Fiber Optics Model” PC-1 Available at:

[pinger-deploy] "PingER Deployment". Available
[qbss] "SLAC QBSS Measurements". Available
[ravot] J. P. Martin-Flatin and S. Ravot, "TCP Congestion Control in Fast Long-Distance Networks", Technical Report CALT-68-2398, California Institute of Technology, July 2002. Available
[tsunami] "Tsunami". Available
[tutorial] R. L. Cottrell, "Tutorial on Internet Monitoring & PingER at SLAC". Available
[udt] Y Gu, R. L Grossman, “UDT: An Application Level Transport Protocol for Grid Computing”, submitted to the Second International Workshop on Protocols for Fast Long-Distance Networks.

[un] "United Nations Population Division World Population Prospects Population database". Available

h. These countries appear in the Particle Data Group diary and so would appear to have HEP programs.



[1] Since North America officially includes Mexico, the Encyclopedia Britannica recommendation is to use the terminology Anglo America (US + Canada).  However, in this document North  America is taken to mean the U.S. and Canada.

[2] In special cases, there is an option to reduce the network impact to ~ 10bits/s per monitor-remote host pair.

[3] Reducing costs is critical when one considers that 1 yr of Internet access > average annual income of most Africans (Survey by Paul Budde Communnications)

[4] Typically satellite links are 300-1000 more expensive in $/Mbits/s than fibre links.