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Use the hop_limit field of MeshPacket to limit max delivery depth in

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the mesh.
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geeksville
2020-05-18 17:35:23 -07:00
parent 53c3d9baa2
commit 26d3ef529e
9 changed files with 51 additions and 33 deletions
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8
docs/software/mesh-alg.md
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@@ -1,12 +1,10 @@
# Mesh broadcast algorithm
FIXME - instead look for standard solutions. this approach seems really suboptimal, because too many nodes will try to rebroast. If
all else fails could always use the stock Radiohead solution - though super inefficient.
great source of papers and class notes: http://www.cs.jhu.edu/~cs647/
reliable messaging tasks (stage one for DSR):
- fix FIXME - should snoop packet not sent to us
- add a 'messagePeek' hook for all messages that pass through our node.
- DONE use the same 'recentmessages' array used for broadcast msgs to detect duplicate retransmitted messages.
- keep possible retries in the list with to be rebroadcast messages?
@@ -14,7 +12,6 @@ reliable messaging tasks (stage one for DSR):
- delay some random time for each retry (large enough to allow for acks to come in)
- once an ack comes in, remove the packet from the retry list and deliver the ack to the original sender
- after three retries, deliver a no-ack packet to the original sender (i.e. the phone app or mesh router service)
- add a max hops parameter, use it for broadcast as well (0 means adjacent only, 1 is one forward etc...). Store as three bits in the header.
dsr tasks
@@ -55,6 +52,8 @@ when we receive a routeError packet
TODO:
- optimize our generalized flooding with heuristics, possibly have particular nodes self mark as 'router' nodes.
- DONE reread the radiohead mesh implementation - hop to hop acknowledgement seems VERY expensive but otherwise it seems like DSR
- DONE read about mesh routing solutions (DSR and AODV)
- DONE read about general mesh flooding solutions (naive, MPR, geo assisted)
@@ -62,6 +61,7 @@ TODO:
- REJECTED - seems dying - possibly dash7? https://www.slideshare.net/MaartenWeyn1/dash7-alliance-protocol-technical-presentation https://github.com/MOSAIC-LoPoW/dash7-ap-open-source-stack - does the opensource stack implement multihop routing? flooding? their discussion mailing list looks dead-dead
- update duty cycle spreadsheet for our typical usecase
- DONE generalize naive flooding
- DONE add a max hops parameter, use it for broadcast as well (0 means adjacent only, 1 is one forward etc...). Store as three bits in the header.
a description of DSR: https://tools.ietf.org/html/rfc4728 good slides here: https://www.slideshare.net/ashrafmath/dynamic-source-routing
good description of batman protocol: https://www.open-mesh.org/projects/open-mesh/wiki/BATMANConcept