Finding neighboring mesh nodes: Difference between revisions
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[[Category:Byzantium]] | |||
= Assumptions = | = Assumptions = | ||
* There is at least one mesh node. | * There is at least one mesh node. | ||
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** Bindings for multiple languages are available | ** Bindings for multiple languages are available | ||
** Protocol in a nutshell: | ** Protocol in a nutshell: | ||
*** Ad-hoc DHS over IP multicast (224.0.0.251) | *** Ad-hoc DHS over IP multicast (224.0.0.251, port 5353/UDP) | ||
*** Each node has a resource record for each service | *** Each node has a resource record for each service | ||
**** SRV | **** SRV | ||
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** Resolution is done by the host running an Avahi implementation - broadcast a resolution request to the multicast domain and listen for a response | ** Resolution is done by the host running an Avahi implementation - broadcast a resolution request to the multicast domain and listen for a response | ||
** Node needs to have its hostname set (machinename.local) | ** Node needs to have its hostname set (machinename.local) | ||
** Ignores point-to-point links by default. Add "allow-point-to-point=yes" in avahi-daemon.conf | |||
*** Do mesh interfaces have the POINTTOPOINT flag? | |||
** wide-area functionality seems relevant to a mesh. | |||
** deny-interfaces=eth0 in avahi-daemon.conf may be necessary to prevent mDNS traffic from going over gateways. | |||
** avahi-daemon implements service announcement and listening, and interfaces with Avahi-enabled client apps. | |||
** avahi-dnsconfd connects to avahi-daemon and keeps track of unicast DNSes detected. | |||
** Read manage for avahi-daemon.conf! | |||
** Will need an /etc/avahi/services/foo.service XML file for each service offered by a node. | |||
*** Manpage avahi.service(5) documents all required XML tags. | |||
** Each mesh node will have a list of all mesh nodes it's heard from in recent memory. This can be used to build the directory of neighboring services. | |||
* XMPP service discovery | * XMPP service discovery | ||
** XEP-0030 | ** Message oriented, based on XML | ||
** Jabber's protocol. | |||
** [http://xmpp.org/extensions/xep-0030.html XEP-0030] | |||
** Used for discovering other XMPP entities/services implemented by XMPP servers. | |||
*** Could be used for discovering and federating apps running on other nodes (i.e., distributed microblog). | |||
* | = Notes = | ||
* KDE comes with something called Personal File Server, which allows arbitrary directories to be made available over HTTP(S?). It's Avahi-enabled. KDE is packagedwith Porteus. There's our file dump. | |||
* | * avahi-bookmarks allows the user to access HTTP resources with a web browser. | ||
* nss-mdns should be enabled in /etc/nssswitch.conf. | |||
Latest revision as of 20:54, 3 April 2012
Assumptions
- There is at least one mesh node.
- Meshes are not built through collusion, i.e., each person setting up a node does not do so knowing that others are as well.
- Mesh nodes are able to broadcast the existence of services they run ("I run a microblog!")
- Services can be activated on a node (implying that their presence will be announced) or deactivated (implying that their presence will not be announced)
- Mesh nodes continually listen for announcements of services from neighboring mesh nodeds
- Mesh nodes maintain directories of services running on neighboring mesh nodes
- ...except when a service is designed to automatically federate with others of a like type (i.e., announcements of content from one will automatically be incorporated into cached announcements on the node)
- Clients neither broadcast nor listen for service announcements
- Smartphones
- MP3 players
- Computers not running Byzantium
Existing protocols
- Avahi/ZeroConf/mDNS
- Included in Porteus Linux
- Host can publish running services
- Host can be informed of services running on other hosts
- User does not have to specifically configure any of this
- Host admins may have to configure this
- Bindings for multiple languages are available
- Protocol in a nutshell:
- Ad-hoc DHS over IP multicast (224.0.0.251, port 5353/UDP)
- Each node has a resource record for each service
- SRV
- TXT
- PTR
- Types documented in /usr/share/avahi/service-types on Windbringer. File is part of Avahi on all systems.
- HAS NOTHING TO DO WITH dnsmasq!
- Resolution is done by the host running an Avahi implementation - broadcast a resolution request to the multicast domain and listen for a response
- Node needs to have its hostname set (machinename.local)
- Ignores point-to-point links by default. Add "allow-point-to-point=yes" in avahi-daemon.conf
- Do mesh interfaces have the POINTTOPOINT flag?
- wide-area functionality seems relevant to a mesh.
- deny-interfaces=eth0 in avahi-daemon.conf may be necessary to prevent mDNS traffic from going over gateways.
- avahi-daemon implements service announcement and listening, and interfaces with Avahi-enabled client apps.
- avahi-dnsconfd connects to avahi-daemon and keeps track of unicast DNSes detected.
- Read manage for avahi-daemon.conf!
- Will need an /etc/avahi/services/foo.service XML file for each service offered by a node.
- Manpage avahi.service(5) documents all required XML tags.
- Each mesh node will have a list of all mesh nodes it's heard from in recent memory. This can be used to build the directory of neighboring services.
- XMPP service discovery
- Message oriented, based on XML
- Jabber's protocol.
- XEP-0030
- Used for discovering other XMPP entities/services implemented by XMPP servers.
- Could be used for discovering and federating apps running on other nodes (i.e., distributed microblog).
Notes
- KDE comes with something called Personal File Server, which allows arbitrary directories to be made available over HTTP(S?). It's Avahi-enabled. KDE is packagedwith Porteus. There's our file dump.
- avahi-bookmarks allows the user to access HTTP resources with a web browser.
- nss-mdns should be enabled in /etc/nssswitch.conf.