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Location and Persistence Based Routing (LPBR) thoughts

December 16th, 2010 No comments

I think that once we have some robust way of relying upon what a location is, we can start to be a little bit more sophisticated with the routing protocol. i.e. making real-time decisions about routing based on the current history, rather than the broad ranking.

For example, extending the idea in PBR which uses duration of contact, and including the idea of Prophet and various others, which use the time since the last meeting with a node, we can use these for locations, and contacts;

Node A keeps a record of contacts and locations, and interrogates
            other nodes on encounter.
On encountering another node B, pass the message for C:
     if B spends more time than A, at any location that node C does
     or B has visited the destination nodes most popular location(s)
           more recently than A
     or B has seen the destination node more recently than A
          ?(and it has a regular pattern (periodicity) of seeing the destination
           node which can be predicted, and means that B will see C
           sooner than A)?
      or B has spent more time than A, with node C in the past

This effectively pushes the message to to the places that the destination node often visits, and to the nodes that see the destination more often.

In a large network, with many very weakly connected communities, it would be difficult to penetrate the destination communities with messages, however, an enhancement to get messages sent widely is to use some other broadcasting mechanism first, such as spray and wait, where there are a limited copies of a message, of which half are shared at every contact until each node has one copy.

At this point the Spray and wait protocol would hold onto the message waiting to see the destination. However, if we then start LPBR routing from this point, we could find that one or some of those messages are with nodes in the destination community, and therefore a greater likelihood of getting the message to the destination.

Categories: Ideas, projects