Tung-Wei Kuo | A New 2-step Consensus Algorithm | CrossLink Taipei 2019

okay since for coming to the last track and we don't have to professor to send their latest book so the plus one is from Asian University province of war and today we present the top care about a consensus that always said it's for tomorrow your table is so it's more common to this presentation I think you've learned reduction so I've noticed that you guys just mark this talk as a best talk so when I say talking backs house assume that this will be boring and there's lots of pros medics patients weird rotations the good news is that is talked mostly improves you are sending a patient so yeah hopefully after we stop your fantasies intuitive software interest well I'm gonna start off by explaining the title as a believe that most of you have some consensus awesome style mistake so today again the talk is a pharmacist a surgeon but we're gonna consider different safety and so you're not a trooper world or prove a stack for popping pop chick in this talk we're going to focus public option would you be invention one so so let me stop you can imagine that with high production and this project we have formulas and we already have four graphs on the run chain and the question now is how to produce and here we only have four months and it's first part dead and they all have their own tender part now the question is which track should be the fifth function and what makes this part difficult is in we all know that imagine we have some forty notes so for the note suggests of not that may not follow protocols or news okay so yes today this is our goal to reach consensus to reach consensus and yeah because with the presence of forty knots we cannot guarantee that all nodes who have to say about you so instead we're going to focus just on the good ones and we want to make sure that all of us care received a setback and as I mentioned earlier how we consider private projects so this just means that best appeared not everyone into the system okay only special ones enjoy the system and in program options we can reach consensus by exchanging masters and usually we design concepts ourselves and for park attractions we have two requirements the first one is called set so in the world of proxy and this just means that you cannot have for interruption and the second is likeness so this is just that you can guaranteed to receive do not okay it's not necessary by phone alone so if a system does not says by blackness for simple this means you may be stuck in substrate like deadlock that prevents your progress if Democrats hey stop next I'm going to divide consensus assets into several groups or into how they form or reach consensus in the normal case so the first group I call in the four-step thousand so these are Arizona selectively reach consensus by just changing message formats in a normal case so same pose includes half-staff so they only need to stretch messages four times in the normal has to copy the problem so we also have some free step houses and here you see some very famous consensus option like ppfd TV ok so now we have four and three so why not - so indeed in nature Ethier trip where we have some to step out comes this velocity of a hyper train and our solution also goes to this ok so if you can somehow lower the number of steps you need to reach consensus this usually implies that the dancing or a response time is smaller so this usually priced at your solution has a good performance so this they are already some two-step consensus Elsa so next I'm going to compare our solution with our two-step process ourselves ok so here I'm just going to these some drawbacks or downside of the other consensus essence and this strength advantage of oscillation so for the first three ourselves the drawback is that cannot guarantee both set the Americas and for the second one SPRT they can guarantee for selfie and likeness but the downside is that when some normal condition habits they need to trust on this we tend to freeze that out so this will increase the response time so this is stuck with so our solution should have a surprise that we can guarantee for safety and lightness and we never use a three-step hours and not an interesting property about our solution is that even if novita so leader is just a note that is responsible for proposing path which I'll get discussed you know what so even if they know that post-party is 40 we still have a chance to reach consensus okay so again it is not stupid you stir that right so next I'm going to just give you some basic ideas that you're going to see investing every consensus helps us for private options so I think every consensus also needs to address the following two questions so the first one is who can propose about so recall that we consider permit projects so this means the set of nodes that are in the proxy is fixed is known in advance so usually were just going to choose one thing frog the nodes the set of nodes and in the nature literature we should refer to this known as the leader so the leader will podcasts that blog post and normally in the future we're going to change the leader multiple times so a more precise question to ask is at this moment who is the leader who can make the proper post so in the first question you can imagine the system follows a miss Debbie and the question is who can post up so in our solution we got a very simple mechanism to determine the leader that is just you suffer occupation so in other words only notes take turnips to peel a teacher well now we've just solved the first question so in the region and it's assumed that now any study now the next question is after I've done that X video how to know whether a is 40 or not trust the detail so we know that some not like a 30 40 so an is or may not power broker or some not like t maybe just be senator pharmacist so cannot trust me so next I'm going to if you're acceptable to show that what may happen if the deal is for okay so in this example you see that alice is 40 bitter and what she did is to say different plants to different users or two different ways okay so you can see that and it's just an orange fact about every prop to death okay so in this I'm going to use different colors to group set different props so now Bob and David is a different life five so problem is if the consensus is not designed well then it may need to afford because it is a different content in abruption okay so that's a fault so obviously we want a port for interruption so best every consensus on some nice new dress decision and it will decide in some sense mechanism to determine whether the diva is 40 or not and the basic idea is to do so what do I mean by peer review so peer review is just the process of knowledge exchange of messages new job so the message of contained information about a drug that he or she just received so based on this information on an audience starts to evaluate the video determine whatever it is for your mat so there you see some examples but first I want to decompose the last cycle by a private option into two parts so in the first part on the Left can see that the leader should generate a back and then we'll cast a black tube ornaments okay so that concludes the first part and the second part we're going to do the clarity so this just we all know starting strange matters yeah so based on this information we're going to appear okay and after the peer review is done inside is remaining to change the video for example the D is 40 so interchanging and then you'll see that if you want to change the even usually this involves some additional message complication so next I'm going to give you two samples so one good example and now that shows what happens we had the biggest fault okay so this is the normal case so here the leader is a good guy so you just said segment two ornaments so see that all aprox okay so this is the first part of the lifecycle and in a single part we're going to start to purely sukira not see since he just received an already proper give just Jeremy knows that she just received an order secretly for not D again you just receive acknowledgement so you're just here on events that you just received and so so after a while after this informations exchanged almost well not that every obviously the same block in other words to Bremen census so that they can commit this original to adoption and that's it let's see what happens in the case where the DJ's portal and that's our period sawfish okay so yeah the beat is funky so he sent different parts to different notes so is the three different colors representing different blocks so in the process of peer review not see what notes that you just receive a green block and of the it just received an orange one and not be just receiving so after a while after this information are propagated that are protested every note would know that basically everyone receives a different one so there's not women so this means in this life cycle this mob rock community okay so this is we need to move forward to the next life cycle so we need to change the heater and a new video so the basic idea of doing peer review is to make sure that whenever you want to come in about if you first make sure that most of the notes have to save them and after that you okay so so far with what if you see I just spend our tricks and ideas that you're going to see basically every consensus hours so next I'm going to give you some more details power outside right so first of all again I want to stress that in some case you need more life cycles to come in at all or to reach consensus and if in in the researcher we also referred to this life cycle as well okay so you know go through many more promised to reach consensus okay so to give you more details about our design okay in fact first I'm going to give you more details about that either about here so you can't think about this question so when can I compete abroad okay so the answer and the magic number here is that when I know that's more than 87 now it's every citizen up then I can come to the problem okay so the other magic number you say you're saying okay so after the peer-review process if you know that wanna exit every citizen table that you can so if you just have this version just provide this version of consensus salesman then actually in some case you will fail okay so next I'm going to give you a fair scenario which are referred to as turbulent River scenario so judging from a name you know that they are two notes to rabbit and again to slow is fast my theory of course sterno is still in terms of the transmission speed or a working speed the rabbit is fast okay and as follows that the turtle and rabbit that both have three runs and three brats only are they about you and what they want to do not is to produce the fourth product and let's see what happens so in the first lifecycle filter is still so best you cannot receive any message and so yeah so since it cannot receive any message so you cannot commit the block however because gram is fast so you can receive messages commits the block and that's a monopolist so for ready the fourth part is speak for other notes well they haven't decided is the fourth part okay so this means turtle and other notes they need to move move forward to the next half cycle so now consider what happens in a second round or Signet life cycle because that we were going to change the leader from my son or occupation so let's assume that service leader and let's assume that sister's leader so he is to send a proposal and thus assume that Chernabog has become which is a prop that is different from the as a piece about community partner event as the fourth point and it's full of that in this life cycle the network condition is fabulous best thing everyone can receive messages to come in around so all modes including natural they can come into this party because the neighbor condition is good and they can receive and our messengers so it short we have four wide curves for the rabbit the Philippine speak for the turtle and animals the fourth part is beautiful so again we have evolved and we don't want to talk analysis so let's try to find the due course of this issue so the reason that we have a forum is because the trailer it has a different okay so the drug caused by the turtle is different which is different from me which I told you committee by rabbit as a fourth now why did the turtle decides to cast people instead of me but the reason is that is topical is generally span Teresa nice time the reason that the ternary system has in front is because he is not aware of anything happens in the first round because of our condition is back for a checkup anniversary so to solve this issue first of all yeah so that's the new clothes so form happens because the leader does not know what happened or in the first room in this except so to solve this issue our idea is to pass down that knowledge in a task to a future ok so more precisely we're going to pass out the results or some partial results of peer review to the future agents so the future eaters and not what happened in the past and based on this information even can produce a correct post and so that let me show you the final person so if you are the leader and if you want to propose a block then you need to first make sure that you have collected more than any set of messages in a previous part these are messages for peer review in the previous one so after you have collectively not enough information to generate the block next when you want to design a content of the bath again you need to determine the content according to the received messages okay so you cannot just make it after a block okay you have to decide content for interesting recipes so I think to this point you may discover that there's a small issue here because here the rule says that if the reader wants to make a post then the dealer must have collect enough information in the previous round and what happens if the reader just analysis and not masters on this if administered in submode we may not have any practical so the question is in this case if you cannot receive any proposal what should you do in the process of you well obvious but obvious option is to say that we haven't receive any profit then you just get us just irrelevant states well I have anticipated Proctor that's it but the question is because that's the intuition of our solutions to best test how the information the habits a path to the future so if you just said that well I have a recipient but then it's like the information propagation just stopped so to further help get the information from the past to the future what we do here is to resend the message that is set in a previous room okay so we're going to set it again in this room so this is like we can keep propagate propagating the information in past to the future okay okay so we have done some preliminary tests and we've written our solution of Gath and construct production position of 100 notes and this 100 nodes are deployed five different data centers each one of them has 20 notes and this results are where we serve access to 500 researchers per second and notice that just by upgrading the VM spec from T to small to large almost double the filament and moreover in this experiment we haven't adopt any of my social skills like message or signification or a thorough signature so a future moment apart these automatic spheres to further improve the performance of house so that's it [Applause] any person the Viper 21 I'm talking it was I went out west I know today enterprise works in services or trivia may I can't happy that dog or your deity Chandra egalitarianism okay so the question is about the disadvantage of our solution and why the magic number is 80% well so it has been shown that if you want to clearly separate happiness using a to step out sir then you need to assume let more than 80 percent of the notes at 40 in other words number of 40 knots is less than 20 percent that's the assumption that you must have to guarantee safety - so you can consider this essay with such reform of our section so in interest of that number 40 notice nest entrance so in other words we can say i under arrest or Tex and if it's like we're able to attend be better suitable like whatever any chance of life because like based on the fact that many of the son of the most of the nose hon as they are goodness so in that case whoever that is is this better you pay us with this condition right been talking to what kind of other other time of efforts that needs to be spent on force - yes in a normal case okay oh wait Don champion turn on ha JA one not all know what cause you get to arriving at Isola the block right so he even saw 80% there in hiding $10 block 5 to internalize don't work I think it's a song block fire right I mean Todd just what I see is a buck for when will gets up the fourth path say homicides will be soon eternity domina so he turn into it turn directly publish on to this haven't ECT so now in eighty percent okay so it took a look what he sounds you should do go rabid I can't really come into the rock okay magic I got already time here so about half of my pasta because it defies pastas it's a higher pronounced it's all students or for some time so it's a by the possible yes so it defines positive time young alpha subunit Arabia to 90 so I certify the positives or directed to sort all talking points about very slowly dinitrogen does anything the God that we demystified Apostle Thomas what's your check that's anywhere okay bye cheers hallelujah so it's not me not you it's just all had to pay about 2,000 apostles that really that's all she showed me that so much as possible until I saw she had to possibly object text so necessary energy assault leader my employee buzzer source event was a regional out of Fort Knox so which is chances X you saw that matter cuz it sounds about audience that's the political community of this out recently reflection of things you know offense every review ever known me to check that all I don't know except for itself so yes as I mentioned in the conclusion in the future would want to get this information initially neuroscientists may not be classified coordinates but if you use a pencil back to aggregate this information I send in this information first to somehow and then the farmer will make this information that has to the government's this will refuse their communication complexity so if I had said okay if there is no question then there's things for professor the most efficient [Applause] you