KadOH Kademlia over HTTP a Javascript framework bringing DHT to - - PowerPoint PPT Presentation

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KadOH Kademlia over HTTP a Javascript framework bringing DHT to - - PowerPoint PPT Presentation

Jun 10, 2023 773 likes •1.19k views

Alexandre Lachze Pierre Guilleminot KadOH Kademlia over HTTP a Javascript framework bringing DHT to mobile applications What have been done so far in the DHT landscape ? * * Distributed Hash Table Theoretical resuts Chord Kademlia

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Kademlia over HTTP

a Javascript framework bringing DHT to mobile applications

Alexandre Lachèze Pierre Guilleminot

KadOH

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What have been done so far in the DHT landscape ?

* * Distributed Hash Table

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Theoretical resuts

Chord Kademlia Improvement proposals

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Public large scale implementations

File sharing eMule BitTorrent’s Mainline

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What is missing ?

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Mobiles

Ignored by DHTs Huge and growing audience Private data

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Web Applications

taking advantage of DHTs scalability

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Beyond file sharing...

  • verlay networks

improving privacy protections

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What have we done ?

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A Javascript framework implementing Kademlia in browsers using XMPP over HTTP

a.k.a. KadOH

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Why Javascript ?

  • improved portability vs. native
  • good performance
  • event-driven asynchronous I/O
  • simplified distribution process
  • automated backward compatibility
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Why XMPP ?

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How to establish peer to peer connections ?

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Common problem on obstrusive cellular networks

highly restrictive firewalls technicaly impossible need a for third party router

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Develop our own router ?

Router

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Develop our own routers ?

Router Router

s2s

distributed

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Develop our own routers ?

heavy does not scale against the end-to-end principle

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Unsing the XMPP infrastructures

GTalk

Jabber.com

peer to peer messaging distributed – already scaled

  • pen
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XMPPprotocol

eXtensible Messaging and Presence Protocol

  • pen and standard

based on XML made for instant messaging and extensible

<message from='juliet@jabber.org’ to='romeo@jabber.org' xml:lang='en'> <body>Art thou not Romeo, and a Montague? &lt;3</body> </message>

TCP

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But in the browser ?

bosh bosh

GTalk

Jabber.com

Bidirectional-streams Over Synchronous HTTP XHR long polling XMPP in browser

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Good news : It works !

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How does it work ?

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ValueManagement

Node RoutingTable

Reactor

KBucket

*

1 1 1 1 1 1

Transport

(XMPP, UDP, ..)

1 1 1

RPC

*

1

FindNodeRPC StoreRPC FindValueRPC PingRPC

IterativeFind

1

*

Architecture

modular extensible independant parts highly hackable

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How to use it ?

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node = new KadOH.Node(id, options)

Instantation

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node.connect(function() { node.join(); });

Connection and joining

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node.put('0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33', 'Hello world !');

Store

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node.get('62cdb7020ff920e5aa642c3d4066950dd1f01f4d', function(value) { alert(value); });

Retrieve

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That’s it !

...but possibility to access to lower level functions

  • r totally rewrite the logic
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Some extra sugar ?

  • runs in Node.js
  • supports various transports :
  • UDP
  • raw XMPP
  • WebSocket
  • connects to the Mainline DHT
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DEMO Proxy to Mainline

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How to test a DHT from scratch ?

  • instantiate a large number of peers
  • automatic behavior – bots
  • heavy computing capacity

Amazon EC2

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EC2 instance

elastic ip

EC2 instance EC2 instance

bot

fork process

bootstraps

XMPP server

bosh

Bar.com

testing device

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DEMO XMPP & DHT simulation

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Benchmarking

  • sequence of iterative look ups
  • 5 non reaching
  • 5 reaching
  • collected relevant metrics on multiple devices
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Benchmarking

5000 10000 15000 20000 250 500 750 1000 1500 2000 3000 3500

Non resolved Iterative find - time (ms)

5000 10000 15000 20000 250 500 750 1000 1500 2000 3000 3500

Resolved Iterative find - time (ms) chrome firefox iphone-wifi iphone-3g

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Let’s sum up.

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A Javascript framework implementing Kademlia in browsers using XMPP over HTTP

< 5s (even in3G)

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KadOH

https://github.com/jinroh/kadoh http://jinroh.github.com/kadoh/

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And now ?

  • still lots of features to implement
  • focus on new promising technologies