Frequently needed answers for Project Byzantium.

As with any project, if you want people to use it you have to make them interested in it. To make them interested in it, you have to tell them about it. In the era where Internet access is considered a fundamental human right by many, finding places to post about what you're working on is easy. So, as one might expect I've been hooking up with Internet activists and technologists wherever and whenever I can to exchange ideas and get the word about Project Byzantium out. However, it seems like I keep answering the same questions over and over again; granted, our wiki pages are set up mostly for developers and not so much for people browsing the site to see what it is that we're about. So, I hope to ameliorate that somewhat with this post by answering the most commonly asked questions and criticisms.

Please note that this entry will likely change over time as new questions are asked and answers change in response to new developments.

What are the goals of Project Byzantium?
The goal of Byzantium is to develop and maintain a distribution of Linux which can run from removable media (such as a CD-ROM, DVD-ROM, or USB storage device) without needing to be installed. This distribution of Linux will include a graphical desktop, a control panel application which configures and manipulates services running on the Byzantium node, and mesh routing software which allows the creation of an entirely separate wireless Internet, functionally indistinguishable from a wireless access point of the sort that you'd find in a coffee shop or at home. The Byzantium mesh network is theoretically uncensorable because it operates in a peer-to-peer fashion and avoids the existing infrastructure of the Net; any computer with a wireless network interface can become a part of the Byzantium mesh. Moreover, every Byzantium node comes with a number of collaboration and communication applications pre-installed, configured, and optimized for use by mobile clients (such as smartphones and MP3 players), from a wiki to a web-chat application to a collaborative word processor. Each application can be individually turned on and off, so a particular Byzantium node doesn't have to run everything all of the time, only the mesh routing software.

We will also write a book and get it translated into different languages which explains how Byzantium works in a manner which is easy to understand, how to set up Byzantium nodes without our distribution of Linux (also easy once you understand how), how to protect yourself if you're running a node, and how to solve some of the thornier non-software problems (such as bridging meshes over distances longer than the unaugmented maximum range of 802.11a/b/g/n). While it would be great if we could include a FabFi kit in every .iso image it's kind of hard to zip up an improvised antenna and cable set sitting on a workbench, so the best we can do is include and attribute the plans so you can build one yourself (at least until general purpose nanoassembly is perfected and we can include free/libre greyprints for one).

Why is the project called Byzantium?
Byzantium draws its name from the fact that we're aiming for Byzantine fault tolerance, which is a fancy way of saying that arbitrary members of the network this project will build can and will get fouled up in arbitrary and surprising ways. Not only could nodes crash for whatever reason, but they could run out of power, a critical USB device could be disconnected, the environment might interfere with wireless broadcasts, a node could overheat, a single process could die, or any number of other things. We aim to mitigate those risks by making it simple and quick to build a large mesh in a short period of time, so that if a few nodes do happen to go dark there will be plenty left over to take over for it (and the dead nodes can be brought back online quickly). Also, if a single process dies it can be easily restarted (or migrated to another node).

What is a mesh network?
A mesh network is a network in which some of the nodes route traffic for other nodes in addition to making services available and acting as clients in the network. In traditional wired or wireless networks every node has a default gateway though which it sends all traffic not destined for adjacent nodes on the local network. If that default gateway goes down the local network is isolated. In a mesh network every node on the local network can potentially act as a gateway for all other nodes within broadcast range. Under the hood of a mesh there is no default gateway, there are only neighboring routers (you can call them gateways if you like but this is actually technically inaccurate) that will relay traffic toward a destination and send responses back to a client. Also, due to the sheer number of routers in a mesh you don't have to worry about your active connections dropping just because you walked three blocks and your smartphone decided that another two or three mesh nodes were its preferred ("default") "gateways"; this is called mobile IP.

To put it another way, because every PC with a wireless NIC running Byzantium Linux is effectively a router, you don't have to go out and buy specialized equipment to set up a mesh. You just have to boot off of a USB key or CD (yes, CD-ROM - we're shooting for tiny here) and off you go.

Aren't meshes notoriously unreliable/inefficient/noisy/unworkable? Or, "Why aren't you using the FooMesh routing protocol?"

Early mesh networks weren't very good. The first experiments with mesh networking used dedicated hardware (and companies still like to build single-purpose modules that cost way too much money for most people to want to experiment with, let alone deploy). Due to the fact that each mesh node has to send broadcasts to neighboring nodes so they can keep their routing tables up to date some older protocols are notoriously inefficient (and this has unfortunately tarred all of them with the same brush). Some mesh routing protocols require that each node maintain a table of every other node in the mesh, and others are entirely too chatty. Also, older mesh routing protocols like OLSR do not attempt to avoid routing loops, which can bring a mesh to a screeching halt (though that problem is being fixed these days). What a lot of people don't realize thanks to first impressions is that newer mesh routing protocols (like the ones that Byzantium is using) learned from these mistakes and sought to not repeat them. A little research on mesh routing protocols will produce a lot of documentation and working, deployed source code that proves that these problems have been resolved. Case in point, the Battlemesh.

At this moment in time, Byzantium has packaged two mesh protocols for full-scale testing, Babel and BATMAN-advanced. Rather than quote their documentation verbatim I encourage you to take a look at the projects' introductory documentation and see for yourselves why we chose these two protocols.

What exactly is in a Byzantium node?
A Byzantium node is any wireless-enabled computer either running Byzantium Linux or has installed software that gives it compatible functionality. At the very least, a Byzantium node has the capacity to distribute network configuration information to wireless clients with DHCP and participate in a wireless mesh network as a router (using 802.11a/b/g). Byzantium nodes are capable of making services available to the mesh they are a part of but it is not expected that everyone will set up a wiki, microblog, or chat system. It is expected that a few Byzantium nodes will be able to distribute configuration information to other Byzantium nodes using ahcp, but just in case the Byzantium control panel application is able to set the network configuration of a node independently and interoperably.

What is Byzantium built with?
Byzantium is being built on top of Porteus Linux, an ultra-lightweight distribution of Linux built using Linux Live. Porteus aims for Slackware compatibility in most respects (including construction and interconversion of packages). To give you an idea of how small Porteus Linux is, the .iso image for v1.0 clocks in around 250 MB. Porteus Linux can be run entirely from a disk or it can be installed to removable media (like a USB key or MP3 player), so Byzantium Linux can be as well.

If Byzantium is a live distribution of Linux, how can I use the mesh? I don't know anything about Linux, I just have an iPhone!
While it's great if you boot Byzantium and set up a mesh node you don't have to. One of our design goals was to make it possible for anyone walking down the street with a smartphone to get on the mesh and use it. Byzantium nodes, as far as your smartphone, netbook, or laptop are concerned, may as well be one of the wireless access points at Starbucks, at home, or at the airport. Your wireless device needs to be capable of ad-hoc wireless networking, and you may need to install an application beforehand to do this.

How do you plan to provide services to users?
In either of our use cases, access to the global Net would be limited at best, likely unavailable. This means that many of the organizational tools that people use today (like Twitter and Facebook) could not be reached by users to exchange information. To remedy this, every Byzantium node will include a pre-installed, pre-configured web application that will fill in for one of those online services ( for Twitter, an as-yet-undecided lightweight social networking site for Facebook, and a wiki). Once we've gathered, installed, configured, and hardened each of those applications for inclusion in Byzantium Linux, the administrator of a running Byzantium node can use the control panel to turn on just the wiki or just the chat system with a few clicks of a mouse. When a web application is turned on, the frontpage of the Byzantium node will be updated to have a link to that application. Additionally, other Byzantium nodes will be notified of the existence of this service, and they will update their frontpages with links to it.

If this is a live distribution, can I save my configuration someplace so I don't have to re-do it when I reboot?
Yes. Porteus Linux (and thus Byzantium) are fully capable of storing data generated while the node is running so that the next time the node is booted it can pick up where it left off (including configuration information and any databases created earlier). Porteus already has a utility which can set up the persistent datastore on removable media (encrypted if you prefer, and if you have reason to fear for your safety or freedom we recommend that you use it) which we will interface with the control panel along with step-by-step instructions.

If there is no central DNS, how do you propose to tell users what's out there?
That's a bit of a trick. It's trivial for a node to put a link to services it's running on its frontpage, but to get neighboring nodes to do so a mechanism of some sort must be used to spread the entry. We looked at a couple of ways of going about this, and we think that the easiest way of going about it is to write our own client/server protocol that will distribute notices about one node's services to at least some of the other nodes in a mesh. When a service is activated on a node, the announcements will be made automatically without further user interaction and will appear on the frontpages of neighboring mesh nodes presently. Work is underway on this subsystem.

Can you provide access to the Internet from a Byzantium mesh?
The short answer is yes.

The longer answer is yes, if a Byzantium node has an active connection to the Internet, and if the ISP is not blocking or filtering traffic of some kind. The mesh routing protocols used with Byzantium were chosen for a number of reasons, among them the capability to detect usable connections to the global net and act as gateways (the "default routers" I mentioned earlier). A feature to activate this functionality will be added to the control panel.

We are also researching the possibility of routing traffic destined for the global Net through Tor. While this is doable, it may not be a good idea for reasons of latency, plus it will probably break the mobile IP functionality of the mesh (meaning that whatever sessions you have running will break, compromising your anonymity in the process).

Can't an attacker set up their own Byantium node?
Absolutely. An attacker can also set up their own wireless access point at your corner coffee shop, their own Tor exit node, and can plug into a switch at your telco's central office and monitor traffic. We can't stop them from doing that (if we could, we would stop people from doing bad things, bring peace to the world, end injustice, and make every backspace and delete key on every keyboard vanish).

Byzantium was designed primarily for people using wireless devices to get online - that means smartphones, the odd MP3 player, and laptop computers or netbooks. That also means that, if it comes down to it, taking cover if you need to is possible. You can get onto a Byzantium mesh from inside a house, a rooftop, inside a vehicle (probably with difficulty due to all the metal), a store, or anywhere else you could reasonably duck out of sight for a few minutes. So far as anyone knows attackers aren't doing radio direction finding to locate users of wi-fi, and one must wonder how useful it would be to do so except in the most exceptional of cases. Direction finding is time-consuming, easy to spot and requires a certain amount of skill. Wi-fi is fairly common in developed areas; in some locations there is so much wireless activity that it can be a nuisance. One person staring intently at their cellphone isn't that different from another unless you're looking over their shoulder or roughing up everyone within visual range. If there is anyone nearby monitoring wireless traffic with readily available software, unless you are the only source of traffic in the area and in view of the observers it would be reasonably easy to blend into the crowd so long as you do not give away information that could uniquely identify you (such as your name or a precise location). Operational security cannot be ignored if you're using a Byzantium mesh.

Do you need help developing or testing Byzantium?
Yes! Absolutely! There are only a few of us working on Byzantium right now. We need:

  • Developers to work on the back end of the control panel (built in Python using CherryPy).
  • Developers to write code that runs under the hood of a Byzantium node, such as shell scripts supporting other functions.
  • Web developers to work on the front end of the control panel (which uses HTML and the Mako template system) and help with the user interface. We need it to be as simple and rapidly usable as possible.
  • People who can help us translate the control panel and documentation into languages other than English. i18n experience would be a plus. At a minimum we need Arabic, Farsi, and Chinese.
  • People to port existing Slackware packages and build new modules for Porteus Linux.
  • People to configure and package web applications for inclusion in Byzantium.
  • Alpha and beta testers! We need to know what works, what doesn't, and what needs to be reworked to be more efficient.
Why haven't you published yet?
A few people have remarked that we have published no whitepapers and presented at no academic conferences since the inception of Project Byzantium. We're not inventing new technologies, we're assembling technologies that have been around for years that no one else has pulled together into a coherent, easy to use system. In many cases, some of this software has never been packaged by maintainers of Linux distributions. The code we're writing is for the user interface, to make it fast and easy to set up and use. We've read the academic papers and watched recordings of the conferences, which is how we selected the technologies Byzantium is built around. There is no need to reinvent the wheel (at least, not right now) when the hard work has already been done, it's just waiting to be used. If nothing else, Project Byzantium obviates the need to track down and pull together software from all around the Net in a hurry, a scramble which may not be possible if the Net is locked down or goes offline entirely. Byzantium is pre-configured with sane and secure defaults for everything, defaults that we've put through their paces time and again because we use it ourselves.

We are going to be at a couple of cons, though. I'll be going to ContactCon in October of 2011, and I also plan on pitching Byzantium as a featured project at hacker conventions, like HOPE. Watch this FAQ for updates...

This work by The Doctor [412/724/301/703] is published under a Creative Commons By Attribution / Noncommercial / Share Alike v3.0 License.