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Messages and data structures used in DSR

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• ROUTE REQUEST messages
  • ROUTE REQUEST message:

    ROUTE REQUEST message = a control message used by the DSR algorithm to discover a source route

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  • Format of the ROUTE REQUEST message:

    ROUTE REQUEST packet format:

    Note:

    The list of nodes in the source route will be: constructed by the nodes that has received the ROUTE REQUEST message !!!

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• Data struture used by the DSR routing
  • The DSR routing uses 2 main data structures (caches) to reduce operational overhead in the route discovery operation:

    "Route Request IDs" cache Source routes cache

    (There are other data structures (caches) used to make the operation more efficient.

    These "minor" data structures Will be introduced later).

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  • "Route Request IDs" cache:

    "Route Request IDs" cache = a cache to save recently used Route Req IDs to minimize the message transmission in the flooding operation When a node receives a ROUTE REQUEST message: The Route Req ID in the ROUTE REQUEST is added to the "Route Request IDs" cache Example: A node will discard another ROUTE REQUEST message that contain a Route Req ID found in its "Route Req IDs" cahce

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  • (Source) Route cache:

    Route cache = a data structure used to store the source routes received in ROUTE REPLY messagse The node will use these source routes first when the node wants to transmit a message !!! A node will only initialize the Route discovery procedure (with will flood) when there is no source route found in the route cache