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Martin Geddes - Lean Networking


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Keynote presentation by Martin Geddes on the future of networking.

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Martin Geddes - Lean Networking

  1. 1. This presentation was given as a keynote at the Illinois Institute of Technology Real Time Communications conference in Chicago on 11th September 2012Martin © 2012 Martin Geddes Consulting Ltd
  2. 2. Cosmologies This presentation is about belief systems – ‘cosmologies’ – and our most basic assumptions about the This is the motion of Marsnature of the (networking) universe. across the sky, as seen on successive nights. Do our models explain observed reality? If not, the model has scope to be improved.
  3. 3. Reality vs Model The ancient Greeks struggled to explain this retrograde motion.Indeed, the word ‘planet’ means ‘wanderer’.
  4. 4. Geocentric Their basic assumption was that the Earth is the centre of the universe. This is an anthropocentric viewpoint.
  5. 5. Everything revolved around theEarth, because that’s where we are, and what could be more important than us?
  6. 6. Geocentric So the explanation for the motion of planets was to appeal to Gods! unknown and unknowable forces.
  7. 7. Then this guy comes along with abetter idea in the 2nd century AD. Ptolemy
  8. 8. Geocentric The planets go in little loops as they go round the Earth.Epicycles! All is explained!
  9. 9. Except that didn’t really account for what we observed. There was a residual motion thatwasn’t explained by epicycles. Sothe basic assumptions had to be re-visited. Copernicus A mere one and a bit millennia later, Copernicus suggests that maybe we (and the Earth) aren’t the centre of the universe after all.
  10. 10. Geocentric Heliocentric His heresy was to say that the Sun was the centre of the solar system, and everything went around that. Which is a shift in the origin of how we reasoned about planetary motion, and required us to let go of the #fail assumption the whole universe revolves around us.
  11. 11. Isaac NewtonThis process of refinement continued.
  12. 12. Geocentric Heliocentric Gravity explained the elliptical motion. #fail Gravity
  13. 13. The Sun turned out not to be the centre either – as we understood galactic structures.
  14. 14. And there were still unexplained residual differences between observed reality and our models. So relativity fills that gap.You Know Who
  15. 15. Phantom Dark Energy Model (2007) This refinement of cosmological models continues to this day.
  16. 16. Networking CosmologiesI am proposing that we need to shift our ‘origin’ and adopt a better cosmology in order to make progress in networking. The existing A suggested dominant improved cosmology… cosmology… “Obese” “Lean”
  17. 17. The rest of this presentation involves Agenda comparing a lot of ‘obese’ and ‘lean’ cosmologies. “Lean Networking” Implications Lean WHAT WHY Conversations & (“Obese HOW Pipes”) Lean Future ofManufacturing Internet, Distributed WebRTC, Network policy Computing
  19. 19. This book introduced thebasic principles that we are interested in, and was a ‘cosmological shift’ in process manufacturing. Theory of Constraints
  20. 20. Bottleneck Every production system has stages of processing raw inputs into valued There is always a outputs. bottleneck somewhere in the system.Supply of Demand raw for finishedmaterials goods
  21. 21. Different Worldviews Batches make sure Cost Throughputthere’s no idle time.Variation just drives Accounting Accounting up unit cost. Focus on Utilisation (Cost) Flow (Throughput) Work unit Batch Single-piece Variation Bad Good Key metric Cost per Unit Lead Time Variation in quantity and quality of demand is ordinary.
  22. 22. Goldratt’s great Aha! Fallacy insight was toidentify this fallacy. A resource standingidle is a major waste. WRONG!
  23. 23. Journey to ‘Lean Anything’ HIGH But you can’t get flow Resource efficiency efficiency this way. Coping with variation requires slack, and you don’t have Are the any.machines busy? The natural tendency of managers seeing idle men and machinery is to make LOW it get busy. Is stuff LOW HIGH produced fast Flow efficiency enough?
  24. 24. Eliyahu M. Goldratt“A plant in which everyone is working all the time is very inefficient.” Busy machinery isn’t the same as creating value, which is from products delivered to customers on time.
  25. 25. Inventory Keeping machinery busy (WIP)upstream of a bottleneck just creates work-in-progress (WIP), which ties up capital,requires storage, and inhibits flexibility.
  26. 26. Journey to ‘Lean Anything’ HIGH So to get toResource efficiency production nirvana, you need to master flow efficiency (i.e. low lead time) first, then figure out resource efficiency. LOW LOW HIGH Flow efficiency
  27. 27. Key features of methodology1. Visualise yourworkflow2. Limit work-in-progress (WIP)3. ERR… THAT’S IT! Goldratt gave us a methodology, which I have grossly oversimplified to these two steps.
  28. 28. Key features of methodology1. Visualise yourworkflow2. Limit work-in-progress (WIP)3. ERR… THAT’S IT!
  29. 29. Cumulative Flow Diagram There are flow visualisation techniques which emphasise the metrics we care about: lead time and WIP. Source:
  30. 30. Key features of methodology1. Visualise yourworkflow2. Limit work-in-progress (WIP)3. ERR… THAT’S IT!
  31. 31. RegulateLimit WIP by preventing more inflow into the Inflow system than thebottleneck can process.
  32. 32. Before we start on networking, let’s practise these techniques. How could we use lean principles to escape from email hell?WARM-UP EXAMPLELEAN CONVERSATIONS
  33. 33. We’re not alone in thinking about this problem in this way. “A lesson from leanmanufacturing”
  34. 34. Aha! Fallacy A human standingidle is a major waste. WRONG!
  35. 35. Bottleneck You really don’t want to spend your life doingemail. And even if you do,there’s a finite amount oftime resource to dedicate to the cause. 24
  36. 36. Journey to ‘Lean Conversations’ HIGH Resource efficiency So how can we lower lead time and WIP to create flow efficiency in our email handling? LOW LOW HIGH Flow efficiency
  37. 37. Key features of methodology1. Visualise yourworkflow2. Limit work-in-progress (WIP)3. ERR… THAT’S IT!
  38. 38. My inbox I don’t keep my emails staring at me from my inbox, as if it was a to-do list anyone can scribble Empty… on.(except new messages since I got off the plane)
  39. 39. I use a product to visualise and prioritise my work – and at a glace see what needs to be done next.Kanban visualisation system
  40. 40. An example ticket,linked back to theoriginal email thatmade the request.
  41. 41. Key features of methodology1. Visualise yourworkflow2. Limit work-in-progress (WIP)3. ERR… THAT’S IT!
  42. 42. Limited WIP My personal workflow I limit WIP to forceme to recognise my I also force myselffinite work capacity. to focus on a maximum of two activities at once. My attention is the bottleneck.
  43. 43. Regulate InflowHow can we do this for email? 24
  44. 44. End ‘inboxbloat’ by limiting WIP“Jane’s inbox has reached its limit of 30 unread items.To resubmit your message at a later time, click here.” “You have sent 3 messages to John.He has a limit of 2 messages outstanding per person. Which message do you want to delete?” Holiday hell: “You have 319 new messages.”– Just send them all back and ask people to re-submit!
  45. 45. That was the salad.INTRODUCING Now for the burger.LEAN NETWORKING
  46. 46. Three kinds of network Network of Network of Possibilities Promises Network of PROBABILITIES TDM circuit world, IMS world NON-DETERMINISTIC STOCHASTIC DETERMINISTIC Manage priority, Manage sessions, control loops Manage flow, admission contention and capacityInternet world and trade loss/delay
  47. 47. UK demo ISP running since 2007 My colleagues have built something that appears impossible in the existing cosmology.Bounded flow isolation Unconditionally stableAssured loss and delay Scavenger traffic The benefits of connections and connectionless… without needing circuits toreserve capacity or congestion control loops!
  48. 48. Aha! FallacyHow? Same as Goldratt – they saw the fallacy common to all networking. A network element standing idle is a major waste. WRONG!
  49. 49. Journey to ‘Lean Networking’ Stop making HIGH Resource efficiency networksmindlessly busy creating WIP Flow efficiency in networks means containing loss and delay to meet the bounds required by the application. LOW LOW HIGH Flow efficiency
  50. 50. Key features of methodology1. Visualise yourworkflow2. Limit work-in-progress (WIP)3. ERR… THAT’S IT!
  51. 51. Improper ProbabilityCumulative Distribution Function See how loss and delay accrue along the path, using a probability mass.
  52. 52. Key features of methodology1. Visualise yourworkflow2. Limit work-in-progress (WIP)3. ERR… THAT’S IT!
  53. 53. Queues areBottlenecks
  54. 54. Delay = WIP Waiting packets are the networking equivalent of WIP.
  55. 55. WIP, WIP, WIP Today’s networks maximise WIP, withTCP/IP being the worst offender.
  56. 56. We use the word ‘idle’ to mean ‘lazy’ as well as to describe a network link that is not transmitting. This gives us a clue we have made aninappropriate moral value judgement
  57. 57. Bertrand Russell “Immense harm is caused by the beliefthat work is virtuous.” What underpins this is a belief that it is morally wrong for links to be idle.
  58. 58. Limit WIP! Instead we should build networks so that theylimit packet ingress to the known downstreambottleneck, and minimise WIP.
  59. 59. Work-That means the most basic assumption built into every network router is wrong – or at least unhelpful and costly. Conserving Queues Work-conserving queues are ones which always transmit if the link is idle and a packet is waiting.
  60. 60. Category Error This is a big deal. Networks don’t The clue seemed to do work! be in the name –‘net-work’ – but theyaren’t machines that do work.They do translocation.
  61. 61. ! Work metaphor !Putting stuff in the wrong place stops you doing something useful, i.e.moving packets can create negative value A lot of the ‘work’ routers do in fact destroys value.
  63. 63. Quality Bandwidth Attenuation Let’s give the old cosmology a Let’s give oursname – the ‘bandwidth’ model. a name too.
  64. 64. And abbreviate it.Bandwidth ΔQ
  65. 65. Shannon solved this‘noise’ stuff for single links; we’re doing it What is ΔQ? for completemultiplexed systems. An idea likeentropy or noise… …with many mathematical representations
  66. 66. Alan Turing assumed Zen of Netwrking this. An ideal network copies data instantly and perfectly Real networks instead create loss and delay And that’s it. All they do is degrade.
  67. 67. Zen of Netwrking Networks are trading spaces This is They aren’t pipes. They important. just allocate thePay attention. degradation compared to ‘instant and perfect’.
  68. 68. Zen of Netwrking Networks are Which can betraded (e.g. drop trading spaces more packetsmeans less delay for the rest) that allocate {loss-and-delay}
  69. 69. Zen of Netwrking Networks are trading spaces They allocate this that allocate disappointment (degradation) to different flows.disappointment
  70. 70. Zen of Netwrking Networks are trading spaces that allocateWhich we give a fancy name quality attenuation
  71. 71. Zen of Netwrking Networks aretrading spaces that allocate ΔQ And make it harder to type.
  72. 72. The Three Fundamental Laws of Networking If you offer a load to a network,1. ΔQ exists loss and delay will happen.2. ΔQ is conserved You can’t un-lose or un-delay stuff.3. ΔQ has two degrees of freedom (for mutable contention) These are the ‘thermodynamic’ laws we Rather like pressure-volume- have to work with and constrain the besttemperature you learnt in school outcome we can deliver.for a piston, networks have load- loss-delay.
  73. 73. So we are working with a different mental model that shifts our origin. Bandwidth ΔQ Networks aren’t about pushingpackets along one behind another. Instead, networks just do inter-That’s an anthropomorphic model process communications with that wrongly treats packets like added loss and delay. physical packages. Inter-process “Beads on a string” comms
  74. 74. Bandwidth ΔQ ∞ In the bandwidth model, a packet is 0 Our origin is ‘zero loss and delay’. That makes the mathematics tractable – assumed to stay at rest until we do rather like putting the sun at the centre‘work’ to push it along. The default is of elliptical orbits and forgetting it takes an infinite time to get there. epicycles.
  75. 75. People talk about ‘quality of service’, but what is this ‘quality’ they talk of? Bandwidth ΔQ Quality is the Quality is the presence of absence of something something positive negativeTheir quality is “priority over Our quality is “the absence of other packets to get work excessive disappointment”. done”.
  76. 76. Bandwidth ΔQ“Megabytes per second” Loss/delay probability distributions. Averages Instants
  77. 77. Bandwidth ΔQ Doing work that creates negative value is dumb. Stop doing it!Work-conserving Non-work queues conserving queues
  79. 79. Two kinds of obesity The Internet folk want you to Network of wildly overprovision networks Network of Possibilities to make quality-demanding Promises applications work. This is expensive. The traditional telco folk want to build lots and lots of parallel NON-DETERMINISTIC networks to DETERMINISTIC separate outOverprovision! different quality requirements. Overbuild! This is expensive. (This doesn’t actually work – but they haven’t figured it out yet, so let’s keep it a secret between you and me.)
  80. 80. Two kinds of obesity Network of HIGH YOU Possibilities Resource efficiency ARE HERE The Internet is stuck here. TCP is designed to saturate networks – i.e. create resource efficiency. It can’t create flow efficiency. LOW NON-DETERMINISTICOverprovision! LOW HIGH Flow efficiency
  81. 81. We have lost control over the customer experience Network PREDICTABLE CHAOTIC componentswithin-bounds quality often behave Transported load at HIGH The Internet is poorly under also unstable at high load all loads and suffers congestion Necessary to collapse effects. manage the load on the network to remain within LOW the predictable region of operation LOW HIGH Offered load
  82. 82. Two kinds of obesity But they’ve gone totally the wrong way since Network of HIGH PromisesResource efficiency then with IMS which creates a horribly Traditional bloated and inflexible telco folk were network. heading the right way with technologies like ATM. YOU LOW ARE HERE DETERMINISTIC LOW HIGH Overbuild! Flow efficiency
  83. 83. Network obesity means LIFESTYLE CHANGES! Nobody wants to Aspiration hear the lean Quantify desired outcomes e.g. how often is it OKnetworking doctor for YouTube to showtell them that their morbid obesity Expectation the “circle of death”? Define quality need Average time to first demands lifestyle frame? MOS score for changes. VoIP apps? Execution Match delivery to requirement How do aspirations map How to make to statistical bounds on loss and delay? Assurance applications fail in the Closing the loop right order when instantaneous demand Did it do what you exceeds supply? expected? How do you know?
  84. 84. This is a new technology to put real-time two-way voice and video into web browsers.SO WHAT?INTERNET, WEBRTC &POLICY
  85. 85. Bufferbloat The phenomenon that Internet This problem won’tengineers struggle to find a resolution explain and resolve without a change in in their current cosmology; attempts cosmology is called to fix it will spawn ‘bufferbloat’. new problems.
  86. 86. We’re not measuring The network the things that Hierarchy of Need actually matter, Applications needfinite bounds on loss Rapid variation in loss and delay to work. and delay cause application failure. 3. Uncontended: Low loss and delay ! 2. Stable: High stationarity ! 1. Feasible: High capacity The bandwidth school of thought Note: exact requirements are application-dependent focuses entirely on capacity. This is not enough.
  87. 87. The Internet has an inbuilt …because TCP breaks basic The Internet’s‘statistical noise’ problem… control theory principles. ‘Global Warming’ problem We’re multiplexing more Dropping flow isolation apps, devices and users together; and doing more real-time applications as + Rising peaks of failure well as bulk data. So bufferbloat-like effects + Loss of stationarity good. Not cause more problems. = More ‘extreme weather events’ (and poor for real-time comms) The Internet is intrinsically unsuitable for carrying all of society’s real-time communications needs.
  88. 88. The guiding ‘end-to-end principle’ onwhich Internet architecture is based is a post-rationalisation of bad design decisions from the 1970s. This has a cost our kids will carry. End-to-end principle
  89. 89. Network Neutrality is ‘beads on a string’ model Has broken philosophical foundations: Value comes from flows with bounded ΔQ – Not individual packets Loss is OK and delay can be good! – It’s not a fault or moral failure to avoid work System of two degrees of freedom (loss/delay) Network neutrality is – Not just one (delay) intellectual nonsense. Butonce most people thought it was obvious the Sun went round the Earth too.
  90. 90. ! Network Neutrality ! In man vs mathematics, the mathematics takes a really hard There are rigorous and meaningful ways of defining non-discrimination. negotiating stance Just not this way.Network neutrality as currently conceived puts regulators in conflictwith the mathematics of statistical multiplexing. The maths will win.
  92. 92. Technological Revolutions & Techno-economic Financial Capitalrevolutions go through Carlota Perez this predictable cycle. Electricity, Steel & Heavy Engineering IT & Telecoms Steam, Coal, Oil, Petrochemicals ? Biotech, Iron, Railways & Automobiles Nanotech 1770 2012
  93. 93. The Turning Point Networking becomes You are here! c.70 years embedded into after transistor everyday life, invisible invented. in the way electricity is. Amazing! Fit-for-purpose It works!We’re done inventingthe basic component technologies – datagrams, smartphones, etc.
  94. 94. The Turning Point ΔQ model fills the intellectual hole Turing Networking has been left behind when he done on a “try it and assumed translocation see” basis, without was instant and perfect.rigorous mathematical foundations. Networking Networking as alchemy as chemistry “Translocatability” now has intellectual foundations as solid as “computability”.
  95. 95. Obese monoservice networks Which means we can begin to treat network obesity caused by excessive consumption of monoservice (single class) networks.
  96. 96. End the Cycle of Failure Select new Build technology networkTweak it Because that really isn’t Tweak network to again working any more. get apps working Build it Get bigger complaints
  97. 97. What we need is… Ubiquitous data transport for a digital society And will be even lesssuitable for what we need in future.
  98. 98. Lean polyservice networks We need to go from ‘black andwhite’ to ‘colour’ networks. Each flow has a different quality (‘colour’) need.
  99. 99. Beyond cloud & internet: Distributed ComputingΔQ is only half of the puzzle. The Internet is mis-architected inother ways. Check out Recursive ΔQ RINAInternet Architecture for how it should be done.
  100. 100. Coming in 2013New book by Martin Geddes: “The Internet isJust a Prototype”
  101. 101. Free newsletter Congratulations, you havesurvived this intellectual assault course. For further intellectual assaults, read my newsletter.
  102. 102. Future of Voice & Telco-OTT workshops London, England October 23rd & 24th www.futureofcomms.comFor a more gentle re-shaping ofyour views on communications, come to a public workshop.
  103. 103. Get in touchMartin Geddes Pleased to hear from you.Founder, Martin Geddes Consulting Ltd Twitter: @martingeddes Email: Additional credits and thanks to: Neil Davies, Peter Thompson, John Day, Fred Goldstein
  104. 104. Thank You