----- Forwarded message from haxwithaxe <m...@haxwithaxe.net> ----- Date: Fri, 19 Jul 2013 01:32:43 -0400 From: haxwithaxe <m...@haxwithaxe.net> To: FreedomBox <freedombox-disc...@lists.alioth.debian.org> Subject: Re: [Freedombox-discuss] Serval Mesh Extenders User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6
On 07/17/2013 12:11 PM, Eugen Leitl wrote: > ----- Forwarded message from John Gilmore <g...@toad.com> ----- > > Date: Tue, 16 Jul 2013 11:17:54 -0700 > From: John Gilmore <g...@toad.com> > To: Eugen Leitl <eu...@leitl.org>, g...@toad.com > Cc: freedombox-discuss <freedombox-disc...@lists.alioth.debian.org> > Subject: Re: [Freedombox-discuss] [HacDC:Byzantium] Re: Serval Mesh Extenders > >> if you expect every single device to be a mesh node in the same >> collision domain within range of each other of course it won't work :P > > It is not obvious that "of course it won't work". A sensible mesh > protocol would avoid congesting its medium, having most nodes avoid > forwarding packets for each other in order to increase the amount of > end-user traffic it could carry. So the real issue is that people > have to manually configure "mesh nodes" versus "end user nodes", generally in most use cases i've seen there are mesh nodes that are setup as APs for non-mesh nodes as well so there is little thinking to be done once the nodes are turned on. there are protocols that say they do more intelligent or less verbose communication but i haven't personally tested any in that way beyond ~28 mesh nodes in a small room. > because if every node is a mesh node, the mesh protocol doesn't work. > This operational requirement of current mesh protocols violates the > principle of least surprise and the zero configuration principle. there will always be a tiny bit of config as a certain amount of collusion is required to get some details matched. with most protocols the collusion amounts to using the defaults and joining the right adhoc network (ala babel). in the case of byzantium we have a preconfigured network so it will just have to (automatically) run the mesh protocol to be usable. > These multiport nodes run a "spanning tree algorithm" together, which > will pick a working subset of multiport nodes and disable forwarding > on the rest, to avoid traffic loops that congest the network. When most if not all of the contemporary, deployed, wireless mesh protocols implement loop avoidance or prevention of some kind. some of which are mathematically proven to prevent loops (so the babel people say). > the network configuration changes, the algorithm adapts within a few > seconds. Networks can have thousands of nodes without running into > scale issues. See https://en.wikipedia.org/wiki/Ethernet for more > details. on a practical level we have complex ways of consolidating the physical infrastructure in wired systems that make having that many wired nodes practical and you can in fact have thousands of nodes in a wireless mesh (not all in the same small room though :P). athens municipal wireless mesh network >1k mesh nodes and is the ISP for a giant chunk of athens, greece. http://www.awmn.net/ << literally all greek to me http://en.wikipedia.org/wiki/Athens_Wireless_Metropolitan_Network > The promise of mesh networks was to offer the same level of end-user > utility and convenience as Ethernet, with radio links rather than > wires. So far that promise has been unfulfilled. i'm too young to have heard that particular promise so my apologies for making assumptions :) by the time i heard about mesh networking, wifi was already at 802.11b. in my opinion wireless mesh is very close in the way of end user friendlyness and way ahead in not needing wires running between each of the nodes. i would even argue in many cases the time and energy spent running cables can be greater than setting up a wireless mesh. there are project like byzantium and serval that are trying to make things as easy as possible for end users. while it might not be the vision the people on roofnet had in mind the infrastructural mesh acting as a backbone for non-mesh clients is a decent short* term solution for several practical problems. some links that may interest you http://www.olsr.org/ - what freifunk, commotion wirelss, and byzantium use http://www.pps.univ-paris-diderot.fr/~jch/software/babel/ - babel which is what byzantium used to use http://bmx6.net/ - bmx6 which is a derivative of batman that is supposed to solve many of the issues that batman-adv has http://battlemesh.org/ - really big wireless mesh shootout and more info on the limits of the different protocols * when we get this whole ISPs not shutting down community/municipal networks in the US and someone writes a decent mesh protocol implementation for windows that doesn't require cygwin :P ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org";>leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://ativel.com http://postbiota.org AC894EC5: 38A5 5F46 A4FF 59B8 336B 47EE F46E 3489 AC89 4EC5 -- Too many emails? Unsubscribe, change to digest, or change password by emailing moderator at compa...@stanford.edu or changing your settings at https://mailman.stanford.edu/mailman/listinfo/liberationtech
