147 lines
7.6 KiB
Markdown
147 lines
7.6 KiB
Markdown
---
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layout: post
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name: 'Waku Update'
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title: 'Waku Update'
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date: 2020-02-14 12:00:00 +0800
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author: oskarth
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published: true
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permalink: /waku-update
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category: research
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summary: A research log. What's the current state of Waku? How many users does it support? What are the bottlenecks? What's next?
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image: /assets/img/waku_infrastructure_sky.jpg
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discuss: https://forum.vac.dev/t/waku-update-where-are-we-at/34
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---
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Waku is our fork of Whisper where we address the shortcomings of Whisper in an iterative manner. We've seen a in [previous post](https://vac.dev/fixing-whisper-with-waku) that Whisper doesn't scale, and why. In this post we'll talk about what the current state of Waku is, how many users it can support, and future plans.
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## Current state
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**Specs:**
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We released [Waku spec v0.3](https://specs.vac.dev/specs/waku/waku.html) this week! You can see the full changelog [here](https://specs.vac.dev/specs/waku/waku.html#changelog).
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The main change from 0.2 is making the handshake more flexible. This enables us to communicate topic interest immediately without ambiguity. We also did the following:
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- added recommendation for DNS based discovery
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- added an upgradability and compatibility policy
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- cut the spec up into several components
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We cut the spec up in several components to make Vac as modular as possible. The components right now are:
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- Waku (main spec), currently in [version 0.3.0](https://specs.vac.dev/specs/waku/waku.html)
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- Waku envelope data field, currently in [version 0.1.0](https://specs.vac.dev/specs/waku/envelope-data-format.html)
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- Waku mailserver, currently in [version 0.2.0](https://specs.vac.dev/specs/waku/mailserver.html)
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We can probably factor these out further as the main spec is getting quite big, but this is good enough for now.
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**Clients:**
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There are currently two clients that implement Waku v0.3, these are [Nimbus](https://github.com/status-im/nimbus/tree/master/waku) in Nim and [status-go](https://github.com/status-im/status-go) in Go.
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For more details on what each client support and don't, you can follow the [work in progress checklist](https://github.com/vacp2p/pm/issues/7).
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Work is currently in progress to integrate it into the [Status core app](https://github.com/status-im/status-react/pull/9949). Waku is expected to be part of their upcoming 1.1 release (see [Status app roadmap](https://trello.com/b/DkxQd1ww/status-app-roadmap)).
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**Simulation:**
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We have a [simulation](https://github.com/status-im/nimbus/tree/master/waku#testing-waku-protocol) that verifies - or rather, fails to falsify - our [scalability model](https://vac.dev/fixing-whisper-with-waku). More on the simulation and what it shows below.
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## How many users does Waku support?
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This is our current understanding of how many users a network running Waku can support. Specifically in the context of the Status chat app, since that's the most immediate consumer of Waku. It should generalize fairly well to most deployments.
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**tl;dr (for Status app):**
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- beta: 100 DAU
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- v1: 1k DAU
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- v1.1 (waku only): 10k DAU (up to x10 with deployment hotfixes)
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- v1.2 (waku+dns): 100k DAU (can optionally be folded into v1.1)
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_Assuming 10 concurrent users = 100 DAU. Estimate uncertainty increases for each order of magnitude until real-world data is observed._
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As far as we know right now, these are the bottlenecks we have:
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- Immediate bottleneck - Receive bandwidth for end user clients (aka ‘Fixing Whisper with Waku’)
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- Very likely bottleneck - Nodes and cluster capacity (aka ‘DNS based node discovery’)
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- Conjecture but not unlikely to appear- Full node traffic (aka ‘the routing / partition problem’)
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We've already seen the first bottleneck being discussed in the initial post. Dean wrote a post on [DNS based discovery](https://vac.dev/dns-based-discovery) which explains how we will address the likely second bottleneck. More on the third one in future posts.
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For more details on these bottlenecks, see [Scalability estimate: How many users can Waku and the Status app support?](https://discuss.status.im/t/scalability-estimate-how-many-users-can-waku-and-the-status-app-support/1514).
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## Simulation
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The ultimate test is real-world usage. Until then, we have a simulation thanks to Kim De Mey from the Nimbus team!
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We have two network topologies, Star and full mesh. Both networks have 6 full nodes, one traditional light node with bloom filter, and one Waku light node.
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One of the full nodes sends 1 envelope over 1 of the 100 topics that the two light nodes subscribe to. After that, it sends 10000 envelopes over random topics.
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For light node, bloom filter is set to almost 10% false positive (bloom filter: n=100, k=3, m=512). It shows the number of valid and invalid envelopes received for the different nodes.
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**Star network:**
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| Description | Peers | Valid | Invalid |
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| --------------- | ----- | ----- | ------- |
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| Master node | 7 | 10001 | 0 |
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| Full node 1 | 3 | 10001 | 0 |
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| Full node 2 | 1 | 10001 | 0 |
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| Full node 3 | 1 | 10001 | 0 |
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| Full node 4 | 1 | 10001 | 0 |
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| Full node 5 | 1 | 10001 | 0 |
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| Light node | 2 | 815 | 0 |
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| Waku light node | 2 | 1 | 0 |
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**Full mesh:**
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| Description | Peers | Valid | Invalid |
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| --------------- | ----- | ----- | ------- |
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| Full node 0 | 7 | 10001 | 20676 |
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| Full node 1 | 7 | 10001 | 9554 |
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| Full node 2 | 5 | 10001 | 23304 |
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| Full node 3 | 5 | 10001 | 11983 |
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| Full node 4 | 5 | 10001 | 24425 |
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| Full node 5 | 5 | 10001 | 23472 |
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| Light node | 2 | 803 | 803 |
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| Waku light node | 2 | 1 | 1 |
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Things to note:
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- Whisper light node with ~10% false positive gets ~10% of total traffic
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- Waku light node gets ~1000x less envelopes than Whisper light node
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- Full mesh results in a lot more duplicate messages, expect for Waku light node
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Run the simulation yourself [here](https://github.com/status-im/nimbus/tree/master/waku#testing-waku-protocol). The parameters are configurable, and it is integrated with Prometheus and Grafana.
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## Difference between Waku and Whisper
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Summary of main differences between Waku v0 spec and Whisper v6, as described in [EIP-627](https://eips.ethereum.org/EIPS/eip-627):
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- Handshake/Status message not compatible with shh/6 nodes; specifying options as association list
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- Include topic-interest in Status handshake
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- Upgradability policy
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- `topic-interest` packet code
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- RLPx subprotocol is changed from shh/6 to waku/0.
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- Light node capability is added.
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- Optional rate limiting is added.
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- Status packet has following additional parameters: light-node, confirmations-enabled and rate-limits
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- Mail Server and Mail Client functionality is now part of the specification.
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- P2P Message packet contains a list of envelopes instead of a single envelope.
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## Next steps and future plans
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Several challenges remain to make Waku a robust and suitable base
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communication protocol. Here we outline a few challenges that we are addressing and will continue to work on:
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- scalability of the network
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- incentived infrastructure and spam-resistance
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- build with resource restricted devices in mind, including nodes being mostly offline
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For the third bottleneck, a likely candidate for fixing this is Kademlia routing. This is similar to what is done in [Swarm's](https://swarm.ethereum.org/]) PSS. We are in the early stages of experimenting with this over libp2p in [nim-libp2p](https://github.com/status-im/nim-libp2p). More on this in a future post!
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## Acknowledgements
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_Image from "caged sky" by mh.xbhd.org is licensed under CC BY 2.0 (https://ccsearch.creativecommons.org/photos/a9168311-78de-4cb7-a6ad-f92be8361d0e)_
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