3.1.2 Timers

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Each receiving node MUST have the following timers:

  • Maintenance timer:

    • This timer SHOULD be triggered immediately when a node is first opened to perform the initial maintenance. If the initial maintenance succeeds in establishing at least one neighbor connection, this timer SHOULD be set to 5 minutes. If the initial maintenance fails to establish any neighbor connections, the second maintenance SHOULD be scheduled after 10 seconds.

      Note After the second maintenance, this timer SHOULD be set to 5 minutes, whether a neighbor connection is established or not.

    • This timer is used to regularly run the maintenance cycle, which examines the neighbor connection set and tunes it for optimal throughput. The duration SHOULD be 5 minutes.

    • The timer SHOULD<2> be triggered immediately if the number of connected neighbors falls below MinNeighborCount.

When the node successfully joins the mesh and connects to at least one neighbor, the following timer is created:

  • MessageID Cache timer: A periodic timer used to initiate MessageId cache maintenance. (This removes previously seen MessageIds to maintain a reasonable cache size.) The period of this timer SHOULD be 1 minute.

If the mesh is secured with a password, the following timer is created for each new connection:

  • Security Handshake timer: Used to close the connection if the remote neighbor does not send a timely response during the authentication protocol. The period SHOULD be 1 minute.

For each connection where the ConnectionState data element is set to the Authenticated value, the following timer is created:

  • Connect Handshake timer: This timer exists to close the connection if the remote neighbor does not send a timely response. The period SHOULD be 1 minute.

For each connection where the ConnectionState data element is set to the Connected value, the following timer is created:

  • LinkUtility timer: This timer exists for each neighbor connection and is used to send a LinkUtility message at regular intervals. The period SHOULD be 1 minute.