We should create a section for these topics in the wiki in some sort of design
space.
~Michael
On Jun 21, 2013, at 6:06 AM, John Blossom <jblos...@gmail.com> wrote:
> Bruno,
>
> Thanks, this is an excellent summary. It helps me to get the gist of things
> more clearly.
>
> On the P2P latency, I don't think that it would be unacceptable to draw a
> line and say that P2P provides limited, non-guaranteed realtime OT or that
> it's not realtime OT and more of a syncing mode than a conversation mode.
> That would probably be sufficient for what needs to be done, especially
> since in some instances P2P-enabled Wave sessions may be using MESH
> networks for transport - a key factor in how a lot of experimental
> communications services are being deployed in developing nations (not just
> the Project Loon concept). In the MESH model, you're likely to have one
> node within range of another temporarily, which may sync with it, and then
> pass along data to another node when it comes in range of it. That's the
> most probable scenario for P2P in many instances, I would think. The other
> potential scenario: two people in a remote location, for the sake of
> argument two movie script-writers who have holed themselves up in a remote
> location to collaborate on a common script. They're on two devices that are
> very proximate to one another, so perhaps the latency issues will not be so
> severe.
>
> Things to think about, I will look at this more carefully later today.
>
> All the best,
>
> John Blossom
>
> On Fri, Jun 21, 2013 at 8:05 AM, Bruno Gonzalez (aka stenyak) <
> sten...@gmail.com> wrote:
>
>> Following Joseph's "A Very Wavey Plan (P2P!)" thread, a couple of
>> discussions have taken place at the irc.freenode.net #wiab channel, all
>> related to P2P.
>>
>> I've taken the liberty to restructure the IRC logs, remove some chitchat,
>> and divide it into sub-discussions. Feel free to reply to any part of this
>> email to continue a discussion.
>>
>>
>> *Summary of discussions:*
>> *====================*
>> *1) Underlying protocol for P2P federation*
>> Currently XMPP is used. HTTP and raw TCP are two suggested candidates (HTTP
>> allowing to much more easily reach restricted networks).
>>
>> *2) Message/event types needed for P2P federation to work*
>> We'd need something similar in concept to certain git operations (git
>> clone, git push...). All will be based on hashes (not incremental
>> integers).
>>
>> *3) Routing p2p messages/events in a server-aided network*
>> One option is to somehow detect server clusters, send data to one of them,
>> and let the rest of the cluster servers synchronize to it (locally).
>> Alternatively, the originator server can naively send stuff to all possible
>> destination servers, regardless of the cost.
>>
>> *4) Routing p2p messages/events in a pure P2P system (5 parts)*
>> How to manage to route all wave-stuff if we want to completely get rid of
>> servers completely, and only use peers.
>> The closest way would be to use a DHT, but huge latency is an unsolved
>> problem, and makes it impossible to use for real-time waving.
>> No other solution has been proposed.
>>
>> *5) Implementing "undo": invertibility, tombstones, edge cases, TP2*
>> No server means no canonical order of commits, which means that undo is
>> hard to do correctly.
>> (uhm... not sure if that's a good summary, some stuff went over my head
>> :-D, please read the log instead)
>>
>> *6) Usability of a pure p2p system in Real Life (tm)*
>> Being pragmatic, pure P2P is probably only usable in peers with good
>> connectivity. Rest of peers will need to rely on a server/proxy that *does*
>> have good connectivity.
>>
>> *7) Comparison with BitTorrent and P2P-TV technologies*
>> Both technologies are much less restricted than wave with regards to
>> real-time responsiveness. So none are really a good reference for our
>> purposes.
>>
>> *8) Identifying participants (3 parts)*
>> Pure p2p means many peers don't have a n...@centralized-server.com user
>> handle, so an alternative has to be used.
>> However, it's easy to provide a traditional friendly handle, if the user
>> prefers the tradeoff of having to often rely on a permanent server. This
>> tradeoff can be mitigated by using a sort of userhandle cache.
>>
>> *9) P2P anonymity (lurking in a wave) (2 parts)*
>> In a pure p2p wave network, anonymous peers may want to read a public wave,
>> without other peers knowing. A solution could be to make private the
>> required wavelets (where the anonymous participants IDs are stored).
>>
>> *10) Encryption of waves*
>> It's been proposed to use an AES key to encrypt all the wave data, and only
>> allow participants to decrypt it.
>>
>> *11) Addition and removal of participants, and their ability to read past
>> and future wave versions/deltas*
>> The aforementioned AES key can change over time, allowing a finer-grained
>> restriction of what deltas new/removed participants can read.
>>
>>
>> *
>> *
>>
>> *Actual conversations:*
>> *====================*
>> *
>> *
>> *1) Underlying protocol for P2P federation:*
>> [in response to Joseph's email]
>> [23:42] <alown> I [...] agree with option 2 (make every root a JSON blob)
>> [23:43] <alown> You haven't really detailed (at all) how the P2P federation
>> is actually going to work (beyond 'not like IRC')
>> [23:44] <josephg> Personally, I'd love some raw TCP action
>> [23:44] <alown> I agree using KISS principle.
>> [23:44] <josephg> a few years ago (not long after wave was cancelled) there
>> was a 'wave summit'
>> [23:45] <josephg> - and a few of us chatted about how we could make the
>> federation protocol simpler
>> [23:45] <josephg> we ended up (somehow) deciding that doing it over http
>> woul dbe a good idea
>> [23:45] <josephg> because then we could sneak it into companies past their
>> corporate HTTP firewalls, etc
>> [23:45] <josephg> but in any case, I'd like to figure out the protocol and
>> (at least) have a TCP version
>> [23:46] <josephg> it should be pretty easy to wrap the same messages in
>> websockets if we want
>>
>>
>> *2) **Message/event types needed for P2P federation to work:*
>> [23:46] <alown> Do we need anything more complicated than the
>> waveletSubmit/Commit messages used currently?
>> [23:46] <alown> (Replace wavelet with 'abstract p2p ot container name)
>> [23:46] <josephg> um, yeah.
>> [23:47] <josephg> we'll also be able to rip out all the code that deals
>> with managing the tree of servers per wave
>> [23:47] <josephg> but yeah - the protocol will get a bit more complicated
>> [23:47] <josephg> ... because we'll lose our beautiful integer version
>> numbers
>> [23:47] <josephg> so we'll need a protocol for syncronizing ops
>> [23:48] <josephg> yeah - ops will each have a hash
>> [23:48] <josephg> and two servers could each have ops the other server
>> doesn't have
>> [23:48] <josephg> so we have to be able to deal with that
>> [23:47] <alown> What other 'events' are cared about by any particular
>> server?
>> [23:47] <alown> For a SHA hash?
>> [23:48] <josephg> -> we'll need something like git's sync protocol
>> [23:48] <alown> So, initial server contact is 'git clone', and then some
>> form of 'git push' on changes?
>> [23:49] <josephg> yep.
>> [23:49] <josephg> push on changes is easy - its basically the same thing we
>> have now
>> [23:49] <josephg> just instead of saying "This should be applied at version
>> 10" we say "This op has parents [abc123, def456]"
>>
>>
>> *3) **Routing **p2p **messages/events in a server-aided network:*
>> [23:49] <alown> With P2P do we have to broadcast to all peers? How do we
>> coordinate that between them?
>> [23:50] <josephg> between servers? I dunno.
>> [23:50] <alown> How does BT handle this?
>> [23:50] <josephg> should we just connect every server to every other
>> server? That'd work fine...
>> [23:50] <josephg> I guess every server can address every other server
>> [23:50] <josephg> beacuse the wave will have al...@a.com and
>> josephg@b.comand so on on it
>> [23:50] <alown> This feels very inefficent...
>> [23:51] <josephg> so if you submit an op to your server, your server can go
>> "Oh, I need to tell b.com about this too"
>> [23:51] <josephg> well, if there's 10 servers, presumably all 10 servers
>> need to find out about ops somehow.
>> [23:51] <josephg> - assuming we stick with the current model of having
>> servers store all your operations
>> [23:51] <josephg> .. and documents for all the users at their domain
>> [23:51] <alown> But server 'b' and 'c' might both be part of a wave, but
>> also know each other, and know that they are 'closer' to each other than
>> 'a' is. So, we would want a->b/c then b<->c
>> [23:52] <josephg> so actually, having the server which originates an
>> operation send it to all the other servers on that wave is actually close
>> to ideal.
>> [23:52] <josephg> yeah maybe.
>>
>>
>> *4) **Routing **p2p **messages/events in a pure P2P system (part 1):*
>> [23:54] <alown> BT uses DHT for its P2P stuff...
>> [23:54] <josephg> ...I guess we could use a DHT storing all the ops, but
>> thats pretty slow
>> [23:55] <josephg> and you still need to notify all servers with users on
>> the wave that the wave was updated.
>> [23:55] <alown> Maybe, or perhaps only notify those within a certain
>> 'distance', with each server doing that. (Though could mean some servers
>> are never updated)
>> [23:58] <alown> Perhaps we could make the network setup 'SuperWaves' which
>> broadcast to all peers, and carry all information, but normal wave servers
>> do not reach this status?
>> [23:58] <alown> By having it decide itself based on how 'connected' a
>> server is, this could find the most efficent ways to route it.
>> [00:01] <josephg> Do you think it'll really be a problem?
>> [00:01] <josephg> I mean, thinking about it - how many servers will be on a
>> given wave?
>> [00:01] <alown> Depends.
>> [00:01] <alown> No idea.
>> [00:01] <josephg> If it were a public wave, I can imagine clients just
>> connecting to one (or more) centralized servers
>> [00:01] * josephg nods
>> [00:02] <josephg> ... But say if we were having a conversation on
>> wave-dev@apache, there's like, at most 20 people in a discussion from 5 or
>> so domains
>> [00:03] <josephg> ... I think we can deal with that kind of load.
>> [00:04] <josephg> but if the protocol lets any server tell any other server
>> about an operation, then it should be pretty easy to set up something like
>> that.
>> [00:04] <josephg> maybe.
>> [00:04] * josephg thinks
>> [00:05] <josephg> hm - you're right. I think I've just gotten used to the
>> crappy state of doing routing for broadcasting messages to a network
>> [00:05] <josephg> if you can find / think of a better solution, I'm in.
>> [00:12] <alown> Heh, anyway replacing the network layer code SHOULD be
>> easy, since it SHOULD be cleanly seperated.
>> [00:13] <alown> Getting an initial implementation up using broadcast is
>> fine.
>> [00:13] <alown> (I was thinking of Wave's use in other apps as a reason you
>> could have a lot of different participant domains)
>> *...4) Routing **p2p **messages/events in a pure P2P system (part 2):*
>> [08:53] <stenyak> as for the "how to *really* do p2p", i see two options:
>> a) use a dht-like algorithm and/or b) use a helper server to route stuff
>> for you
>> [08:54] <stenyak> a) can be pretty slow if you want all OPs to reach all
>> peers (if I'm not mistaken)
>> [08:54] <stenyak> and b) is essentially makes it not-p2p
>> [08:55] <stenyak> additionally, using p2p, how are we going to deal with
>> routing problems (such as firewalls on both sides, etc)?
>> [08:56] <stenyak> in my mind, the only universal solution is to have a
>> third party server available to go through if we want speed or if we want
>> to work on all edge cases
>> [08:56] <stenyak> and wave being advertised as realtime, i don't see how
>> something like dht can ever fly
>> [11:20] <alown> stenyak: This is why I was wondering about a DHT system
>> with 'Superwave' servers (to act as a first point of contact).
>> [11:59] <stenyak> that would be like skype dynamic supernode list?
>> [11:59] <alown> The original system, yes.
>> [12:02] <stenyak> so we would devise a method to identify candidates to
>> being a supernode, in order to prevent cellphone wave peers from becoming
>> one, and in order to promot certain other nodes (like major peers that have
>> 99% uptime, e.g. wave.google.com or whatever) to become one
>> [12:03] <stenyak> bandwidth, latency, open ports, uptime...
>> [12:04] <alown> Once a network has been bootstrapped using something, it is
>> relatively easy to identify the hosts which are most densely connected (and
>> would be good supernode candidates)
>> [12:05] <stenyak> what do you mean with "using something"?
>> [12:06] <alown> Somehow the network has to initially be able to make
>> contact with other nodes (before it knows anything about them)
>> [12:07] <alown> For a LAN you could get away with a broadcast 'announce',
>> but it is a bit less clear on an internet-sized scale.
>> [12:08] <stenyak> bittorrent sync uses a broadcast for LAN. for internet it
>> uses a tracker server for fast discovery of peers, or you can disable that
>> and force to use DHT (with the long wait that means)
>> [12:09] <stenyak> the tracker can also act as a meeting-point for
>> firewalled peer pairs (which in my experience is a lot of them)
>> [12:09] <alown> Precisely the problem, because we don't really want long
>> waits or trackers.
>> *...4) Routing **p2p **messages/events in a pure P2P system (part 3):*
>> [12:42] <stenyak> hmmm... i'm not sure how a peer gets a list of waves in
>> which he's a participant of
>> [12:43] <alown> Having a canonical source makes it all so much easier. :P
>> [12:44] <stenyak> for pure p2p peers to "receive" new waves, either the
>> FROM or the TO peer (or both) would need to try to find their way to the
>> other
>> [12:44] <stenyak> and we're assumign here that each person only runs one
>> peer
>> [12:45] <stenyak> e.g. my privatekey may be used by 5 wave peers at the
>> same time, and we must make sure the new wave reaches all of them
>> [12:46] <alown> Looks like we may need to have mulitple DHTs then (one for
>> ops, one for waves)
>> [12:46] <stenyak> in BT, it's the receiver end who actively looks for peers
>> to receive from. in wave, it's not like that..
>> [12:46] <alown> Or could we have a pubkey->wave mapping in one?
>> [12:46] <stenyak> and in BT, you can assume *many* people has the data you
>> want
>> [12:46] <stenyak> in wave, its possible and probably that only one other
>> peer in the universe has the wave
>> [12:46] <stenyak> (because it's a personal wave sent to you)
>> [12:47] <alown> I would expect any long-running supernodes to be implicitly
>> part of all waves they know about.
>> [12:47] <alown> Though on second thought, this seems like it would add its
>> own problems to authentication, storage, promotion of supernodes etc.
>> *...4) Routing **p2p **messages/events in a pure P2P system (part 4):*
>> [12:51] <alown> Does it make sense for a peer to have your privkey, since
>> you could be logged in anywhere, so it would be down to the place you are
>> logged in, to 'subscribe' to that wave on the network, and attempt to
>> retrieve all data from it...
>> [12:55] <alown> I was expecting the network as a whole to act like a
>> WaveBus pubsub system, whereby once 'logged in' at some server (which means
>> it gets your privkey from the authentication system), that server then
>> 'subscribes' to your waves on the 'network'. If somebody else at some other
>> server changes it, then that server would be announcing to the network of a
>> change (doesn't necesserily have to be a broadcast), which your server
>> would 'hear'.
>> [12:56] <alown> You could do this from any server where you logged in
>> (hence the concept of a domain is lost).
>> [12:57] <stenyak> by "server" you mean supernodes?
>> [12:57] <alown> Not necessarily.
>> [12:59] <stenyak> this pubsub network must be aware of nodes that are in
>> it, in order to directly route wave updates to them, correct?
>> [12:59] <stenyak> and also, this network wouldn't be very volatile, but
>> would rather ideally be long-lived peers?
>> [13:00] <alown> It has no reason to have to directly route updates, (though
>> it would hopefully be able to identify the best routes automatically).
>> [13:00] <alown> Yes it would require a few long-lived peers (which would be
>> part of the requirement to be a supernode).
>> [13:01] <stenyak> so let's say i connect my laptop wave peer to the
>> "server" in the living room, at my firewalled home. this "server" would be
>> already subscribed to the pubsub network, and in this specific case it
>> would route all wave updates to me
>> [13:02] <stenyak> in other cases (let's say, ipv6-enabled nodes everywhere,
>> no firewall at home), the living room server could simply notify the
>> original "FROM" peer to send stuff to my laptop ipv6 ip, right?
>> [13:03] <alown> That sounds right. Supernodes are really only needed for
>> getting the routing right.
>> [13:05] <stenyak> ok. in both these theoretical cases, the "server" hasn't
>> necessarily been a wave node per se (nor a supernode either), but rather a
>> second type of wave node that helps get stuff quickly wherever it's needed
>> [13:05] <alown> Yes.
>> [13:05] <alown> I am not even sure where OT should be happening in this
>> picture...
>> [13:05] <stenyak> if OT happens, the "server" is a blind proxy i think
>> [13:06] <stenyak> so does not need the privkey to work
>> [13:07] <stenyak> unless we're also using OT in the wavebus pubusb network
>> for some reason?
>> [13:07] <alown> Supernodes can be blind (though they might also just be
>> normal well-connected wave servers). I would expect normal servers to still
>> be doing OT. The question is whether the 'client' (whatever that means)
>> should be doing it also.
>> [13:08] <alown> The network shouldn't need OT. (Algorithms exist that allow
>> the incoming ops to be arbitarily queued and only processed when needed).
>> [...]
>> [21:21] <josephg> alown: the client always needs to do OT because otherwise
>> they can't both edit a document live and receive operations from people who
>> didn't have their ops.
>> [21:22] <josephg> the server doesn't need to do OT, although if it doesn't
>> do OT, it'll punt the OT work to its clients - which will result in a
>> higher CPU utilization on mobile devices.
>> [...]
>> [13:08] <stenyak> i pictured this "server" as being an optional item that
>> shortcuts the long waits of DHT, rather than something necessary for
>> "clients"?
>> [13:08] <alown> Hmm.
>> [13:08] <alown> I suppose we should define what a 'client' is then...
>> [13:09] <alown> We have at least 2 layers of stuff going on here: 1) Wave
>> OT/operation layer 2) Network routing/P2P layer
>> [13:13] <alown> But it is quite plausible something might be doing both of
>> those
>> [13:10] <stenyak> with your pubsub net suggestion, i was picturing 2 kinds:
>> a regular pure p2p peer, and a helper kind of node to route stuff quickly
>> when a peer is connected to it
>> [13:13] <stenyak> so with that picture in mind, layer 1 stuff could go
>> directly from peer to peer (if connectivity/firewalls allows), or through
>> the "helper node" if available
>> [...]
>> [13:20] <stenyak> [...] all this discussion looks very similar to
>> discussing how to design internet+dns, i think the problems are the same
>> really
>> [13:20] <stenyak> or at least we could take some inspiration from it maybe
>> [13:20] <alown> This was my conclusion last night with josephg. ('The
>> problmes should already be solved (see The Internet)')
>> [14:09] <stenyak> and The Internets solved the problem how? By having a
>> large set of supernodes (dns servers), that may take a whole day to
>> propagate updates. The alternative being having the actual IP address in
>> the first place, or to centralize stuff
>> [14:10] <stenyak> (aka use servers everywhere)
>> [14:22] <alown> Maybe, but the internet's design is X (where X > 20) years
>> old, so may not represent the most modern thinking of how to make
>> distributed networks.
>> [14:59] <alown> (Don't forget that our aim for Wave is at the cutting-edge
>> of academic research also).
>> [...]
>> [14:50] <stenyak> i just threw the question at some friends who should be
>> more up-to-date with networking technologies than me... hopefully they
>> comeback with some revolutionary dns-2 design or something that we can copy
>> [15:18] <stenyak> could give as some ideas: http://openpeer.org/
>> [15:18] <stenyak> (it's not a solution, but maybe they did the same
>> reasoning we're going through)
>> [15:46] <stenyak> another response i got goes along the lines of... hard as
>> fuck, but if you manage to do it, you are a hero
>> [...]
>> [15:02] <stenyak> looking at it from a wider perspective, what we want is
>> similar to having each peer shout at the whole world "here i am, anything
>> got something for meeee?" in some way that doesn't clog the internet tubes,
>> and that is so fast as shouting would be. i start to think it's not
>> physically possible to do that...
>> [15:03] <stenyak> if publickeys were handed to people based on the
>> location, then we could have routing tables similar to how internet
>> currently works
>> [15:03] <stenyak> but pubkeys are... well, random. so that kind of routing
>> that allows anyone to connect to an arbitrary IP in a matter of
>> milliseconds is impossible, i believe
>> [15:04] <alown> So, we end up with DNS for public keys?
>> [15:04] <stenyak> something like dns, but much faster [wrt. propagation
>> times]
>> [15:05] <stenyak> so in essence, a tree of servers or whatever (which is
>> similar to how wave currently works, right?)
>> [15:05] <alown> Heh. But the whole point was to avoid the tree system
>> currently (since it is susceptible to netsplits)
>> [...]
>> [15:56] <stenyak> maybe the real question could be: how do we make DHT much
>> faster?
>> [16:14] <stenyak> once the initial discovery process is finished, the
>> transmission of data will not have the lag associated with DHT, so even if
>> DHT takes 10 seconds, that could be acceptable
>> [16:15] <stenyak> i.e. a new peer takes 10 seconds to be discovered by the
>> rest of participants collaborating in a wave
>> [16:16] <stenyak> (or viceversa.. the new peer takes 10 seconds to discover
>> the participants)
>> [...]
>> [16:25] <stenyak> this could shed some light:
>>
>> http://en.wikipedia.org/wiki/Distributed_hash_table#Algorithms_for_overlay_networks
>> [19:06] <stenyak> http://dsn.tm.kit.edu/english/2936.php
>> *...4) Routing **p2p **messages/events in a pure P2P system (part 5):*
>> [21:03] <josephg> [...] For now, I want wave to be p2p in the same way that
>> git is p2p.
>> [21:04] <josephg> that is, I want the core algorithms & data structures to
>> use P2P-capable algorithms, and probably the wave servers will do p2p
>> between themselves (this is easy because they'll all be both named and
>> accessable)
>> [21:06] <josephg> as for client-to-client p2p, there's a few options
>> depending on what kind of use cases we want to support - but I want to
>> worry about getting the algorithms p2p-capable first. If you're keen to set
>> up an anonymous, distributed wave system over a DHT - well, I want to first
>> make that possible
>> [21:15] <josephg> .... and as for ipv6, network admins _love_ NAT now that
>> we have it
>>
>>
>> *5) Implementing "undo": invertibility, tombstones, edge cases, TP2:*
>> [00:17] <alown> I am not sure how an 'undo stack' is going to work (at all)
>> with federation...
>> [00:18] <josephg> well, you just do undo at the application level
>> [00:19] <josephg> "submit op which inserts text" ... later "submit op which
>> removes text"
>> [00:19] <josephg> you don't need OT for that.
>> [00:20] <josephg> I imagine like, a semantic undo. In the client you can
>> imagine making an undo op (which might not necessarily rollback an
>> operation (because of tombstones and all that))
>> [00:20] <josephg> ... but would seem that way as far as the user is
>> concerned
>> [00:21] <josephg> then if the user hits ctrl+z, you can transform that
>> operation up to the current version and apply it
>> [00:21] <josephg> - the fact that its an undo isn't really relevant.
>> [00:21] <josephg> the bad thing about losing invertability is doing
>> playback
>> [00:21] <josephg> - because you can't scrub back through time
>> [00:21] <alown> But you have all the operations since the start, so you can
>> play forward at least?
>> [00:23] <josephg> yeah exactly.
>> [00:23] <josephg> ... and make like, keyframes of the document
>> [00:23] <josephg> - and play forward from them or something.
>> [00:23] <alown> Hmm, so you can do the step-back without recalculating the
>> entire document?
>> [00:24] <alown> I don't really like the idea of then having another
>> datastructure to have to pass around...
>> [00:24] <josephg> right - if you have a snapshot at version 1000, and the
>> user is looking at 1010 and they try to step back to 1009, you can just
>> replay ops 1001-1009 on that version 1000 snapshot
>> [00:24] <alown> What was the problem with invertible operations (I don't
>> understand OT enough yet to be able to properly comment on that side).
>> [00:25] <alown> (Other than it confuses people?)
>> [00:25] <josephg> hahaha actually people seem to love invertability
>> [00:25] <josephg> I don't know why.
>> [00:25] <josephg> I've been trying to remove it from sharejs, and everyone
>> gets sad.
>> [00:26] <josephg> the problem is that if I make an op which deletes the
>> whole document (version 100, say) then I undo that operation
>> [00:26] <josephg> and you insert in the middle of the document at version
>> 100, then your op gets transformed to do that insert at the start of the
>> document instead at version 101 (because the content has disappeared)
>> [00:26] <josephg> and it never goes back to the middle of the document.
>> [00:27] <josephg> so, with tombstones you can get around that by having a
>> 'resurrect' operation
>> [00:27] <josephg> (so deleting the whole document turns the whole document
>> into tombstones, then we can resurrect them all again in the inverse)
>> [00:28] <josephg> but you can't invert an insert - because deleting leaves
>> the tombstone there
>> [00:28] <josephg> and if you have a 'real delete' operation, then yeah,
>> you're back in the hole
>> [00:28] <josephg> also, with wave in particular, inverting is really
>> complicated
>> [00:29] <josephg> - see, if the wave says "<annotation bold:true>blah
>> blah<annotation bold:false> not bolded"
>> [00:29] <josephg> then if you insert at the end of the "blah blah", it'll
>> automatically get bolded.
>> [00:30] <josephg> ... so if the text isn't bolded, and then you bold it
>> while I insert at the end of the text, you need to make sure my text
>> _isn't_ bolded or something
>> [00:31] <josephg> .... and yeah, I can't remember - but there's these
>> horror cases that I remember kept me from sleeping when I tried to
>> reimplement wave's OT code in C
>> [00:31] <alown> hmm
>> [00:31] <josephg> and it would have been fine if it wasn't invertible.
>> Well, at least it would have been tollerable.
>> [00:33] <josephg> So yeah. Conclusion: You can make invertability work, but
>> its kind of a bitch, and you can't make it work for TP2
>> [00:33] <josephg> which means it won't work if we're federating
>> [00:33] <alown> How are we hacking around that currently then?
>> [00:33] <josephg> well, we don't do TP2
>> [00:34] <josephg> remember, federation just uses a bad version of the
>> current client-server protocol
>> [00:34] <josephg> - arranged in a tree of servers
>> [00:34] * alown goes and looks up which one TP2 was again
>> [00:35] <josephg> ... its the one that says you don't need a canonical
>> ordering of operations
>> [00:35] <josephg> sharejs and wave both use the server to pick the order of
>> operations (based on which order they reach the server)
>> [00:35] <josephg> and then they use incrementing version numbers based on
>> that order
>> [00:35] <alown> ah yep.
>> [00:35] <josephg> -> for p2p, that doesn't work because you don't have a
>> centralized server, and anyone can send messages to anyone
>> [00:36] <josephg> and yeah, you need TP2 for that (which sort of says you
>> can apply ops from 3 different sites in any order and it still works)
>> [00:37] <josephg> - and apparently someone proved that if you make it work
>> for 3 sites, it works for any number of sites
>> [00:43] <alown> Anyhow, I can see leaving inversion out for simplicity, but
>> don't yet understand why it can't be made to work with TP2.
>> [00:59] <alown> Hmm. Seen 'A Sequence Transformation Algorithm for
>> Supporting Cooperative work on Mobile Devices'?
>> [01:02] <josephg>
>>
>> http://research.microsoft.com/en-us/um/redmond/groups/connect/cscw_10/docs/p159.pdf
>> ?
>> [01:15] <alown> The main feature is its use of storing local/remote
>> operations and processing them much later than receipt time.
>> [01:17] <alown> ABT satisfies TP1+2, so looks like this should(?)
>> [01:19] <josephg> need to read it
>> [01:19] <josephg> ... I'll go through it later
>>
>>
>> *6) Usability of a pure p2p system in Real Life (tm):*
>> [12:13] <alown> We also don't know if storing ops in a DHT is efficent
>> enough for our use case...
>> [12:14] <stenyak> in any case, let's say i fire up my wavep2p android
>> client and want to check for any new waves
>> [12:14] <stenyak> i definitely won't put up with a wait of 30 seconds when
>> i have "this damn fast 4g connection!" in my cellphone
>> [12:14] <stenyak> i mean, that's the point of view of six pack joe
>> [12:14] <stenyak> and joe is definitely right..
>> [12:15] * alown thinks of the hours it took to download the bitcoin
>> blockchain from the p2p system
>> [12:15] <stenyak> or browse through freenet, or whatever... its painly slow
>> [12:16] <stenyak> in the end, i think that most users won't be running a
>> full blown peer, but will be relying on an external server instead
>> [12:16] <stenyak> i.e. nobody runs their own email servers nowadays
>> [12:16] <stenyak> and the same can happen with wave
>> [12:16] <alown> Should a mobile client be doing the full p2p federation, or
>> simply talking to a server which does it...
>> [12:16] <stenyak> the few who decide to run a full-blown wave peer, should
>> be aware of the problems
>> [12:17] <alown> So, this should be less of a problem since the only nodes
>> doing p2p will be proper full-time connected servers?
>> [12:17] <stenyak> the thing is, we can assume most people wont fire up
>> their own xmpp server, but go for jabber.org account
>> [12:17] <stenyak> and the same thing will presumably happen for wave,
>> simply because it's easier to do
>> [12:18] <stenyak> which doesn't pervent me from running my own full-blown
>> wave server
>> [12:18] <stenyak> but that's a use case in which the user knows the
>> limitations
>> [12:19] <stenyak> [...] you and i will run several full-blown wave peers at
>> home, at our parent's house, or whatever, but we'll know and accept the
>> problems
>> [12:19] <stenyak> i think that's the way to think about the problem
>> [12:19] <stenyak> heck, most people use github for permanent [git]
>> connectivity ;-)
>> [12:19] <stenyak> instead of opening ports to their laptop in their lan
>> [12:19] <stenyak> and those are the tech-savvy people...
>> [12:20] <alown> So, we have a p2p system between wave servers and superwave
>> servers, with clients connecting to the server rather than doing the p2p
>> itself...
>> [12:20] <stenyak> i'm not saying it's the way we should do it. i'm saying
>> that's the way it most probably will pan out, because it's already
>> hapennign in 100% of the existing p2p protocols i know of
>> [12:20] <alown> Hmm...
>> [12:21] <stenyak> so we should plan for that instead of a theoretical pure
>> p2p world
>> [12:21] <stenyak> if we assume there's servers like github, bitbucket and
>> sourceforge, then suddently most of the problems go away, while still not
>> preventing from people to run fully p2p if they want
>>
>>
>> *7) Comparison with BitTorrent and P2P-TV technologies:*
>> [12:21] <alown> BT doesn't have huge servers (and with magnet has actually
>> move in the opposite direction).
>> [12:21] <stenyak> BT has no real-time needs
>> [12:22] <stenyak> that's why they can afford DHT
>> [12:22] <stenyak> dht could be used for simulating a forum-like discussion
>> in wave. but we can't force that restriction from the server
>> [12:22] <stenyak> (i say forum-like, because people don't expect reaction
>> within seconds there)
>> [12:23] <alown> How did iplayer do its live p2p broadcastinºg?
>> [12:23] * stenyak googles what iplayer is
>> [12:23] <alown> Sorry, BBC iPlayer is their TV-over-the-internet system.
>> [12:24] <alown> Originally it used a p2p system, but got lots of negative
>> press (because of assosciation with BT since it used p2p), so it now uses a
>> centralized system instead. (And their bandwidth costs are much higher).
>> [...]
>> [12:25] <stenyak> i seem to recall other [p2p] tv clients
>> [12:25] <stenyak>
>>
>> http://wiki.xbmc.org/index.php?title=HOW-TO:Play_free_P2P_(peer-to-peer)_online_streaming_TV
>> [...]
>> [12:26] <alown> Found a paper titled "RT-P2P: A Scalable Real-Time
>> Peer-to-Peer System with Probabilistic Timing Assurances" (google for it)
>> [12:28] <alown> Lookt at the paper I mentioned. It relies on 'super nodes'
>> to enable it to keep low latencies...
>> [...]
>> [12:27] <stenyak> but i'd be wary of using this (p2p tv) as an inspiration.
>> i know there's delay of 10-30 seconds from my TV Formula1 image to the
>> telemetry that comes through HTTP from formula1.com website. this is
>> regular TV, and they don't care about 30 seconds of lag
>> [12:27] <stenyak> the only real problem of p2p tv is avoiding much jitter
>> [12:27] <stenyak> as long as the stream arrives and is viewable, a delay of
>> a minute doesn't matter that much
>> [12:28] <alown> True.
>>
>>
>> *8) Identifying participants (part 1):*
>> [12:09] <alown> I am also no longer sure what an 'account' should look
>> like, since it has no reason to be stuck to a domain...
>> [12:10] <stenyak> current wave discovery works by using the domain name of
>> the email-address-like list of participants
>> [12:10] <stenyak> but here we're talking about hashes, public keys or
>> whatever
>> [12:10] <stenyak> which do not (necessarily) point to an particular IP:PORT
>> or whatever
>> [12:10] <alown> Exactly the problem...
>> *...8) Identifying participants (part 2):*
>> [12:33] <stenyak> would it make sense that, while some participants are
>> identified by a pubkey (or whatever), many of them could be identified by a
>> user@domain address, with which any peer can quickly locate supernodes?
>> [12:33] <stenyak> i mean some kind of dual "pubkey and optional domain
>> email-like addr" for the participants list
>> [12:34] <stenyak> the optional part being essential in the broader internet
>> [12:34] <alown> Isn't that exactly what using Mozilla Persona would do (map
>> user@domain to some public-key we can use)
>> [12:34] <alown> Removing the need for us to have to roll yet-another
>> authentication system.
>> [...]
>> [12:38] <stenyak> the idea would be that, for a person to be a participant
>> in a wave, you *require* his pubkey. optionally, you may have acquired ths
>> pubkey by asking "wave.google.com" about the user "joe", getting his
>> pubkey
>> as a result.
>> [12:39] <stenyak> and now that you have the pubkey and one of many possible
>> email-like addresses (in this case j...@wave.google.com), then you can use
>> the email-like address for displaying in the UI
>> [12:39] <stenyak> this means that, whoever wants to run pure p2p peers,
>> will have to give his pubkey
>> [12:39] <stenyak> and whoever uses the more traditional style, can simply
>> give his email-like addr
>> [12:39] <stenyak> and the participants list will show a simple email-like
>> address most of the time
>> [12:40] <alown> Do we then allow anyone to 'log in' to any wave server
>> running at any domain, since it should no-longer make any difference where
>> they are in the network...
>> [12:41] <stenyak> yes, that's needed for world-wide-public waves, which is
>> equivalent to a read-only forum on the net
>> [12:41] <stenyak> then there could be server-public waves, which is
>> equivalent to requiring sign-in to view a forum (and coincidentally the
>> current implementation of public waves in WiaB, right?)
>> [12:43] * alown has never tested what happens with public waves in the
>> current federation system
>> *...8) Identifying participants (part 3):
>> *
>> [21:35] <josephg> - Who is a user? If a user is sten...@example.com, then
>> we can put a server at example.com and it can hold operations for you
>> [21:36] <josephg> ie, if I add you to a wave, my computer (or my wave
>> server or something) can send a message to example.com to say "Yo, here's
>> some ops you should know about"
>> [21:36] <josephg> that would be similar to a mailbox
>> [21:37] <josephg> ... and it would work pretty well. Bear in mind that
>> there's no reason operations have to go through the wave server at
>> example.com - if we're both on a LAN together, we could discover one
>> another through DNS service discovery and send ops directly
>> [21:37] <josephg> .. without going through our respective wave servers
>> [21:38] <josephg> However - if our identities aren't tied to a domain (eg
>> bitcoin), then we'll need to use a dht or something.
>> [21:42] <stenyak> the conclussion i've arrived at is that "users"
>> ultimately are a publickey (for which they have the privatekey). this is
>> inconvenient for people to "add you to a wave", so a possibility would be
>> to have a friendlyname=>pubkey server converter. this way people can add "
>> sten...@example.com", by first finding out what the pubkey for
>> sten...@example.com really is
>> [21:43] <stenyak> the friendlyname would be optional, and in LAN
>> environments you could directly use the pubkey (instead of the friendly
>> name)
>> [21:43] <josephg> I think people will be more than happy to use a frienly
>> name in a lan environment too
>> [21:43] <stenyak> discovery in a local network could be done with bonjour
>> or something too (not just dns)
>> [21:44] <josephg> I <3 dns-sd
>> [21:44] <stenyak> [...] maybe they already have a contact list (read, list
>> of friendlyname<>pubkey equivalences) they can use in the UI (even if the
>> underlying system will use pubkeys anyway)
>> [21:44] <stenyak> and by contact list, i really mean a cache of some sort
>> [21:45] <stenyak> (not some specific, complex roster system)
>> [21:45] <josephg> and you can do friendlyname -> pubkey really easily by
>> just storing the pubkey on the user's domain
>> [21:45] <josephg> so, have the example.com webserver host
>> https://example.com/.wellknown/stenyak
>> [21:46] <josephg> = your public key.
>>
>>
>> *9) P2P anonymity (peers that want to anonymously lurk in a wave) (part
>> 1):*
>> [12:48] <stenyak> by the way, what about non-participants that simply want
>> to lurk a wave?
>> [12:49] <stenyak> e.g. i'm given a wave uri
>> (wave://look_at_these_kittens_wave), and want to view it
>> [12:49] <alown> Whilst a wave is public, as soon as they 'read' the wave,
>> they would have a metadata wavelet created, so would become a participant
>> (if read-only).
>> [12:50] <stenyak> and from then on, whenever the wave changes, someone will
>> try to make the change reach the peers with my privkey
>> [12:50] <stenyak> supposedly..
>> *...9) P2P anonymity (peers that want to anonymously lurk in a wave) (part
>> 2):*
>> [21:18] <josephg> stenyak: interesting point about people who want to not
>> participate but follow a wave anyway - its really bad if other people can
>> tell that they're there (assuming the wave is public).
>> [21:18] <josephg> I guess we just need to make sure that the metadata wave
>> is invisible, and then its ok..
>> [21:21] <stenyak> invisible.. to what peer/s? surely those that are
>> transmitting deltas to the lurkers will need to know they exist?
>> [21:21] <stenyak> (maybe some of the algorithms behind freenet can help
>> with this)
>> [21:21] <stenyak> (or even TOR)
>>
>>
>> *10) Encryption of waves:*
>> [21:47] <josephg> for waves themselves, I'm imagining giving each wave an
>> AES key
>> [21:47] <josephg> then storing an encrypted version of the key for each
>> participant on the wave
>> [21:48] <josephg> .... anyway, that way anyone who has the AES key can read
>> all ops on the wave
>> [21:48] <josephg> and can participate (because they can encrypt ops for the
>> wave)
>>
>>
>> *11) Addition and removal of participants, and their ability to read past
>> and future wave versions/deltas:*
>> [21:48] <stenyak> what about removing a user from a wave?
>> [21:49] <josephg> worst case, we can just make a new key and re-add
>> everyone using the new key
>> [21:49] <josephg> and keep around the old key too
>> [21:49] <josephg> so people can still read the old ops as well
>> [21:49] <stenyak> the user can access their browser cache for all we care.
>> if you ever read it, there will be ways to do it. "download now wave-spy to
>> read waves you were removed from!"
>> [21:49] <stenyak> so providing an official way sounds better
>> [21:50] <stenyak> the AES key could change at any point in time, e.g.
>> whenever a new users is added (to prevent them accessing the history), or
>> deleting them (to prevent them from reading future history)
>> [22:32] <josephg> um - in wave, we let new users see the whole history
>> [22:40] <stenyak> but that use case could be desirable, right? and if we
>> support modification/versioning of the AES key, we might as well allow that
>> too? the equivalent in email world would be to forward an email, removing
>> the existing quotes
>> [23:17] <josephg> Yep definitely.
>>
>>
>> --
>> Saludos,
>> Bruno González
>>
>> _______________________________________________
>> Jabber: stenyak AT gmail.com
>> http://www.stenyak.com
>>
