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How is the Internet Performing?

How is the Internet Performing?. Les Cottrell – SLAC Lecture # 2 presented at the Workshop on Scientific Information in the Digital Age: Access and Dissemination ICTP, Trieste, Italy October , 2009 www.slac.stanford.edu/grp/scs/net/talk09/ictp-perform.ptt. Overview.

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How is the Internet Performing?

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  1. How is the Internet Performing? Les Cottrell – SLAC Lecture # 2 presented at the Workshop on Scientific Information in the Digital Age: Access and Dissemination ICTP, Trieste, Italy October , 2009 www.slac.stanford.edu/grp/scs/net/talk09/ictp-perform.ptt

  2. Overview • Internet characteristics • Users, capacities, satellites, packet sizes, protocols, routing, flows • How is it used apps etc. • How the Internet worldwide is performing as seen by various measurements and metrics • Application requirements • Comparisons with Development Indices

  3. USERS

  4. Internet Usage growth ‘95-’10 1500 1000 500 Asia Europe N Amer L Amer Africa M East Austrlasia Millions of Users 0 200 400 600 Millions of users N America Australia Europe L America M East Asia Africa World Penetration % Year 0 20% 50% 80% 95 00 05 09

  5. Example: China • China not connected to the Internet until May 1994 • 1st permanent IHEP/Beijing used satellite via SLAC • www.computerworld.com.au/article/128099/china_celebrates_10_years_being_connected_internet

  6. Internet city connections Where are they 2.8% growth/year ~¼ world pop uses Internet Developed world saturating Developing catching up 73% penetration US 43% users from Asia Internet Users 2002

  7. Capacities

  8. What have they got? Capacity Capacity From Telegeography

  9. Who is still on Satellite GEOS • GEOS (Geostationary Earth Orbit Satellite) • good coverage, but expensive in $/Mbps • broadband costs 50 times that in US, >800% of monthly salary c.f. 20% in US • AND long delays min RTT > 450ms, usually much larger due to congestion Min RTT (ms) Terrestrial Easy to spot Clear signature

  10. Packet sizes & types

  11. Packet size • primarily 3 sizes: WHY? • close to minimum=telnet and ACKs, 1500 (max Ethernet payload, e.g. FTP, HTTP); ~ 560Bytes for TCP implementations not using max transmission unit discovery Mean ~ 420Bytes, median ~ 80Bytes Measured Feb 2000 at Ames Internet eXchange Packets ~ 84M packets, < 0.05% fragmented Cu,mulative probability % Bytes Packet size (bytes)

  12. Internet protocol use • There are 3 main protocols in use on the Internet: • UDP (connectionless datagrams, best effort delivery), • TCP (Connection oriented, “guaranteed” delivery in order) • ICMP (Control Message protocol) TCP dominates today SLAC protocol flows ICMP In TCP Flows/10min UDP Out Time Feb-May 2001

  13. Routing

  14. Hops • Hop counts seen from 4 Skitter sites (Japan, S. Cal, N. Cal, E. Canada, i.e. 10-15 hops on average Weak RTT dependence on hop count 95% RTT 50% 5% Hops Hop Count

  15. Richness of connectivity • Angle = longitude of AS HQ in whois records • Radius=1-log(outdegree(AS)+1)/(maxoutdegree + 1) • Outdegree = number of next Hops As’ accepting traffic • Deeper blue & red more connections • All except 1 of top 15 AS’ are in US, exception in Canada • Few links between ISPs in Europe and Asia

  16. Today’s routing less via US www.nytimes.com/2008/08/30/business/30pipes.html • Invented in US • 1st 30 yrs most traffic thru US • 70%=>20% in 10yrs • No central control • Patriot act=>store info outside US • China, India, Japan making larger investments • More level playing field • Harder for CIA!

  17. Routes are not symmetric Advanced to U. Chicago • Min, 50% & 90% RTT measured by Surveyor • Notice big differences in RTTs • May be due to different paths in the 2 directions or to different loading RTT ms U. Chicago to Advanced RTT ms

  18. Flows

  19. Flow sizes SNMP Real A/V AFS file server Heavy tailed, in ~ out, UDP flows shorter than TCP, packet~bytes 75% TCP-in < 5kBytes, 75% TCP-out < 1.5kBytes (<10pkts) UDP 80% < 600Bytes (75% < 3 pkts), ~10 * more TCP than UDP Top UDP = AFS (>55%), Real(~25%), SNMP(~1.4%) Can roughly characterize as power law with slope & intercept

  20. Flow lengths • 60% of TCP flows less than 1 second • Would expect TCP streams longer lived • But 60% of UDP flows over 10 seconds, maybe due to heavy use of AFS at SLAC • Another (CAIDA) study indicates UDP flows are shorter than TCP flows Measured by Netflow flows tied off at 30 mins TCP outbound flows Active time in secs

  21. Applications

  22. Usage • P2p hit by RIAA law suits • Moving to video, social networking • Video on demand double/2 years ’08-’13 • iPhones (only peripherally a phone) • Mobile traffic doubles each year Yahoo YouTube Google Facebook

  23. How it is used & when asert.arbornetworks.com/2009/08/the-internet-after-dark Enterprise & tier 1

  24. Web use characteristics • Size of web objects varies from site to site, server to server and by time of day. • Typical medians in 2000 varied from 1500 to 4000 bytes • Also varies by object type, e.g. medians for • movies few 100KB to MBs, postscript & audio few 100KB, text, html, applets and images few thousand KB • Size of average web page tripled in 5 years 2003-2008 • www.websiteoptimization.com/speed/tweak/average-web-page/ Bytes

  25. Why increasing • New users (easier for user, more coverage) • New apps: You-Tube, climate modeling … • New tools: manual(hand tuned) Automatic generation • Web 2: Ajax, Javascript, CSS • Broadband more elaborate/attractive designs possible • desktop to web apps • e.g. mail, calendars, photo albums, games...

  26. Impact on backbones: e.g. Current and Historical ESnet Traffic Patterns • ESnet Traffic Increases by10X Every 47 Months, on Average Apr 2006 1 PBy/mo. Nov 2001 100 TBy/mo. July 2010 10 PBy/mo. Jul 1998 10 TBy/mo. 53 months Oct 1993 1 TBy/mo. Terabytes / month Aug 1990 100 MBy/mo. 40 months 57 months 38 months Log Plot of ESnet Monthly Accepted Traffic, January 1990 – December 2008

  27. Performance by Metric

  28. What does performance depend on? • End-to end internet performance seen by applications depends on: • round trip times • packet loss • jitter • reachability • bottleneck bandwidth • implementation/configurations • application requirements • Data transmitted in packets

  29. RTT from SLAC to the World RTT ~ distance/(0.6*c) + hops * router delay Router delay = queuing + clocking in & out + processing msec. ITU G.114 300 ms RTT limit for voice 2/3 countries of world Ok for voice, rest mainly in Africa What is the problem with > 300ms?

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

  31. Jitter • Variability of RTT, many ways to measure • “Jitter” = IQR(ipdv); ipdv(i) =RTT(i) – RTT(i-1) • Usually at edges, so ~distance independent • Impacts smooth flows e.g. VoIP, video, real-time • Haptics (surgery) < 1ms; H.323 <40ms with buffer Can improve voice with de-jitter buffer, e.g. 70ms to smooth the flow But…. Internet Jitter seen from SLAC to World Sep’08

  32. Losses • On good lines usually congestion • Wireless dB loss, net devices • Usually last mile • Distance independent • Big effect • Realtime, games, Voice, typing echo • 1% loss VoIP annoying

  33. Derived Throughput Derived throughput ~ 8 * 1460 /(RTT * sqrt(loss)) Mathis et. al Behind Europe 5 Yrs: Russia, Latin America, Mid East 6 Yrs: SE Asia 9 Yrs: South Asia 12 Yrs: Cent. Asia 16 Yrs: Africa Central Asia, and Africa are in Danger of Falling Even Farther behind In 10 years at the current rate Africa will be 1000 times worse than Europe 1993 33

  34. Where is best Throughput?

  35. Voice over IP • Affected by: • Loss, RTT, Jitter, • Quality measured by Mean Opinion Score (MOS) • Can convert from RTT, loss & jitter to MOS • MOS values: 1=bad; 2=poor; 3=fair; 4=good; 5=excellent. • Typical reasonable range for Voice over IP (VoIP) is 3.5 to 4.2. • Russia and L.America improved dramatically in 2000-2002 as moved from GEOS to terrestrial. • US, Europe, E. Asia, Russia and the M East (all above MOS = 3.5) good. S.E. Asia marginal, S. Asia need a lot of patience • C. Asia and Africa are pretty much out of the question in general.

  36. Application requirements • Based on ITU Y1541 & Stanford (Haptics) • The VoIP loss of 10^-3 used to be 0.25 but that assumed random flat loss • actual loss is often bursty • Tail drop in routers • Sync loss in circuits, bridge spanning tree reconfiguration, route changes

  37. Compare with Development Indices Choose most: up-to-date, countries, important factors HDI & DOI

  38. Human Development Index • 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 education gross enrollment ratio (with one-third weight) • A decent standard of living, as measured by GDP per capita (or Purchasing Power Parity (PPP) in US$). • http://www-iepm.slac.stanford.edu/pinger/pinger-metrics-motion-chart.html

  39. HDI vs Throughput • Dot size=population, color =region • Bottom left = bad (Africa, blue), top right=good 0.4 0.6 0.8 1 HDI 100 1000 10000 Throughput (kbps)

  40. Digital Opportunity Index • DOI tracks infrastructure, opportunity & utilization • Strong Correlation, less subjective • PingER throuphut Quicker/easier to update cf DOI R2 = 0.67 DOI 0 0.2 0.4 0.6 0.8 Throughput (kbps)

  41. What’s next • Mobile devices • 40G (transAtlantic, US) & 100Gb backbones • On demand dynamic dedicated services (layers 1 & 2) • Reserve a path at some bandwidth for some time • Use QoS to deliver • HEP, Radio Astronomy, climate research • IPv6

  42. Questions & more study • www.internetworld.stats.com • www-iepm.slac.stanford.edu/pinger • www.slac.stanford.edu/comp/net/wan-mon/tutorial.html • www.slac.stanford.edu/xorg/icfa/icfa-net-paper-jan09/report-jan09.doc • Question: why a Dolphin for a PingER Logo

  43. IP Addresses pingable June 2003 • From CAIDA, SDSC • Grey= not allocated • Black= not pingable • Companies own class A 43

  44. Growth 2003-2006 • More areas allocated, • Existing areas more colorful June 2003 Nov 2006 44

  45. Cumulative RTT distributions • Gives quality measure • Seen from San Diego, US Skitter • Steeper = less jitter, i.e. better • Small values better Cumulative % RTT ms

  46. Throughput also depends on window ACK • Optimal window size depends on: • Bandwidth end to end, i.e. min(BWlinks) AKA bottleneck bandwidth • Round Trip Time (RTT) • For TCP keep pipe full • Window (sometime called pipe) ~ RTT*BW • Can increase bandwidth by orders of magnitude • If no loss Throughput ~ Window/RTT Src Rcv t = bits in packet/link speed RTT

  47. Loss seen from US to groups of Sites 50% improvement / year ETSI DTR/TIPHON-05001 V1.2.5 threshold for good speech

  48. 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

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

  50. How are the U.S. Nets doing? In general performance is good (i.e. <= 1%) ESnet holding steady, still better than others Edu (vBNS/Abilene) & .com improving

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