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3.4
E2 Wireless I/O
WIBMesh
The ELPRO WIBMesh protocol is based on the “Ad hoc On-demand Distance Vector”
(AODV) routing algorithm which is a routing protocol designed for ad hoc networks.
AODV is capable of unicast (single addressed message) and multicast (Broadcast to all) routing and is an “on-demand” protocol, meaning that it builds and maintains these routes only as long as they are needed by the source devices. Another words the network is silent until a connection is needed. The Protocol creates a table, which shows the connection routes to other device in the system and uses sequence numbers to ensure the routes are kept as current as possible.
When a module in a network needs to make a connection to another module it broadcasts a request for connection. Other modules forward this message, and record the module address that they heard it from, creating a table of temporary routes back to the starting module. If a module receives a message and it already has an existing route to it, it will send a message backwards through the temporary route to the requesting module.
Each request for a route has a sequence number. Modules use this sequence number so that they do not repeat route requests that they have already passed on. Another such feature is that the route requests have a "time to live" number that limits how many times they can be retransmitted. Another such feature is that if a route request fails, another route request may not be sent until twice as much time has passed as the timeout of the previous route request.
The original starting module then begins using the route that has the least number of hops. Unused entries in the routing tables are recycled after a time.
When a link fails, a routing error is passed back to a transmitting node, and the process repeats.
