ictp-oct02

Monitoring Internet connectivity of Researchand Educational Institutions : 

1 Monitoring Internet connectivity of Researchand Educational Institutions Les Cottrell – SLAC/Stanford University Prepared for the workshop on “Developing Country Access to On-line Scientific Publishing", 4-5 October 2002, Trieste, Italy http://www.slac.stanford.edu/grp/scs/net/talk/ictp-02.html Partially funded by DOE/MICS Field Work Proposal on Internet End-to-end Performance Monitoring (IEPM), also supported by IUPAP

Outline : 

2 Methodology Results Round trip times Loss Summary Outline

Measurement Architecture : 

3 Measurement Architecture Uses existing ubiquitous Internet ping infrastructure, no tools to install Hierarchical vs. full mesh, each monitoring site chooses remote sites Lightweight – low network impact (100bits/s/path) no special machines trivial to add monitored sites Runs continuously since 1995 WWW Archive Monitoring Monitoring Monitoring Remote Remote Remote Remote HEPNRC Reports & Data Cache Monitoring SLAC Ping HTTP Archive 1 monitor host remote host pair

PingER Measurement Methodology : 

4 PingER Measurement Methodology Measurement host admin choose remote hosts of interest sends 21 pings each 30 mins to each chosen remote host Records RTT, loss, jitter, unreachable, out of order … Records data in local cache Archive host gathers data from measurements hosts regularly (at least daily) Archives, analyzes and generates reports from data Make reports and data publicly available via the web Requirements: Remote host: need a host accessible to pings, and a contact in case host does not respond (almost no effort) Monitoring host: a low end host to make measurements, file space for cache, admin to install toolkit, choose remote hosts, build configuration file, respond to archivers in case unable to get data & keep it running (<<10% FTE) Archive site: probably about 20% of an FTE

PingER deployment : 

5 PingER deployment Measurements from 34 monitors in 14 countries Over 600 remote hosts Over 72 countries Over 3300 monitor-remote site pairs Measurements go back to Jan-95 Reports on RTT, loss, reachability, jitter, reorders, duplicates … Countries monitored Contain 78% of world population 99% of online users of Internet Mainly A&R sites Monitoring Sites Remote Sites

Results : 

6 Results

History - Round Trip Time (RTT) : 

7 History - Round Trip Time (RTT) Improving by 10-20% year More direct paths Replacing satellites with land lines Satellite >~550ms Faster lines & network equipment Lower limit speed of light in fiber Typical lower limit today ~ distance/(0.3 * (0.6 * c)) Speed of light in fiber

RTT to world from US : 

8 RTT to world from US Note large number of satellite links (> 600ms dark red) Note reduction by Aug 2002 Jan 2000 Aug 2002

Impact of loss on applications : 

9 Impact of loss on applications Email fairly insensitive to quality, may be delayed but keeps retrying for days and eventually gets through Web usually has human but expectations are low, performance often more limited by server, human present so can retry Bulk file transfer unattended, if > 10-12% loss connections can time out Interactive telnet, voice very time & loss sensitive E.g. telnet/ssh loss of > 3% severely impacts typing ability, voice sensitive at lower losses Importance of loss/performance

History - Loss : 

10 History - Loss Loss more critical than RTT Losses cause timeouts of typically seconds 40-50% improve/yr Best networks below 0.1% Russia, SE Europe, China several years behind

History – Loss Quality : 

11 History – Loss Quality Fewer sites have v. poor to dreadful performance More have good performance (< 1%)

Loss to world from US : 

12 Loss to world from US Using year 2000, fraction of world’s population/country from www.nua.ie/surveys/how_many_online/

Losses: World by region, Jan ‘02 : 

13 Losses: World by region, Jan ‘02 <1%=good, <2.5%=acceptable, < 5%=poor, >5%=bad Russia, S America bad Balkans, M East, Africa, S Asia, Caucasus poor

History - Throughput quality improvements from US : 

14 History - Throughput quality improvements from US TCPBW < MSS/(RTT*sqrt(loss)) (1) (1) Macroscopic Behavior of the TCP Congestion Avoidance Algorithm, Matthis, Semke, Mahdavi, Ott, Computer Communication Review 27(3), July 1997 80% annual improvement ~ factor 10/4yr ~Factor 100 improvement in 8 years

History – one Research ISP : 

15 History – one Research ISP 100% growth in traffic/yr for last 12 years Continuous upgrades Increase packet size (bulk throughput apps)

History – One large Research Site : 

16 History – One large Research Site

Detailed example of improvements : 

17 Detailed example of improvements Increase of bandwidth by factor of 460 in 6 years, more than kept pace - factor of 50 times improvement in loss Note valleys when students on vacation

Summary - results : 

18 Summary - results Internet A&R connectivity performance is improving RTT 10-20%/yr, loss 50%/yr, throughput 80%/yr Reduced use of satellites, mainly use for new hard to get to areas (e.g. S. Russian Republics) China, S.E. Europe, Russia rate of change keeps up but several years behind India, S. America performance is where N. America & W. Europe were 4 – 5 years ago Improvements need constant investments to understand & improve

Summary - PingER : 

19 Summary - PingER Lightweight (100bps/host pair, 21 pings/30mins per pair) Easy to deploy (uses ubiquitous Internet ping infrastructure) Very useful for inter-regional and poor links Easy to deploy for monitoring of sites in developing countries SLAC would be willing to assist Provide me (cottrell@slac.stanford.edu) with contact and name of host to be monitored

Help : 

20 Help Looking for better hosts to monitor & contacts in: Albania, Armenia, Austria, Azerbaijan Macedonia*, Turkey*, Yugoslavia Columbia*, Venezuela*, Cuba, Mexico* Pakistan Africa (apart from Egypt, Uganda & South Africa, n.b. all 54 countries in Africa now have Internet access in capitals) Note there are a few countries (about 5% of the world’s countries) that do not have full Internet connections and pay dearly by the byte. A couple of years ago these included: Afghanistan, Western Sahara, Christmas Island, S. Georgia, Marshall Islands, Myanmar, Montserrat, N. Korea, Pitcairn, St Vincente & Grenadines

More Information : 

21 More Information IEPM/PingER home site: www-iepm.slac.stanford.edu/ African connectivity http://www3.sn.apc.org/africa/afrmain.htm

RTT from California to world : 

22 RTT from California to world Longitude (degrees) 300ms 300ms RTT (ms.) Frequency RTT (ms) Source = Palo Alto CA, W. Coast E. Coast US W. Coast US Europe & S. America Europe 0.3*0.6c Brazil E. Coast Data from CAIDA Skitter project

Worldwide Connectivity 1997 : 

23 Worldwide Connectivity 1997

Growth in African & Mid E. connectivity 1993 - 1997 : 

24 Growth in African & Mid E. connectivity 1993 - 1997 Internet email None

Africa connectivity : 

25 Africa connectivity See http://www3.sn.apc.org/africa/afrmain.htm 1996 2001

Africa Internet Hosts Jan 1999 : 

26 Africa Internet Hosts Jan 1999 S. Africa Egypt