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Routing Table

Warning: Make sure to read and understand how to Create Luos containers before reading this page.

The routing table is a feature of Luos allowing every containerSoftware element run by Luos that can communicate with other containers. It can be a driver or an app. (Initially called a module) to own a "map" (or topology) of the entire network of your device. This map allows containers to know their physical position and to search and interact with other containers easily.
This feature is particularly used by apps containers to find other containers they need to interact with. The routing table is shared by the container which launches the detection to other containers, but only apps containers store the routing table internaly.


The routing table is automatically generated when a network detections is initiated by a container and shared with other containers at the end of the detection. A detection can be initiated by any container, but driver containers should not be able to run it and this kind of features should be only used on app containers by including routingTable.h an using this routing table API.

To run a detection, type:


where app is the container_t pointer running the detection.

A non-detected container (not in the routing table) has a specific ID of 0. At the beginning of the detection, Luos erases each container's ID in the network, so all of them will have the ID 0 during this operation. You can use it on your containers code to act consequently to this detection if you need it (for example, a container can monitor its ID to detect if a detection has been made and if it has to reconfigure its auto-update).

Then the container running the detection will have the ID 1 and the other containers will have an ID between 2 and 4096, depending on their position from the container detector. The IDs are attributed to the containers according to their position from the detector container and to the branch they are in. The ID attribution begins first to the PTPA port, then PTPB, etc. When each container in the network has an attributed ID, the detection algorithm proceeds to the creation of the routing table and shares it with every containers (saved only one time per node).

Sometimes, multiple containers in the network can have the same alias, which is not allowed to prevent container confusion. In this case, detection algorithm will add a number after each instance of this alias on the routing table.

Warning: Be careful that during a detection, a container can change ID depending on the container running this detection. Do not consider your container's ID fixed. Also, be aware that every containers remove their auto-update configuration during the detection to prevent any ID movement.


As explained in this page, nodesHardware element (MCU) hosting and running Luos and hosting one or several containers. can host multiple containers. To get the topology of your device, the routing table references physical connexions between your nodes and lists all the containers in each one of them.

The routing table is a table of a routing_table_t structure containing nodes or containers information. The maximum number of containers and nodes are managed by the precompilation constant MAX_containerS_NUMBER (set to 40 by default).

routing_table_t routing_table[MAX_CONTAINERS_NUMBER];

The routing table structure has two modes: container entry mode and node entry mode.

typedef struct __attribute__((__packed__))
    entry_mode_t mode;
        struct __attribute__((__packed__))// CONTAINER mode entry
            uint16_t id;                // Container ID.
            uint16_t type;              // Container type.
            char alias[MAX_ALIAS_SIZE]; // Container alias.
        struct __attribute__((__packed__))// NODE mode entry
            // Watch out, this structure has a lot of similarities with the node_t struct.
            // It is similar to allow copy of a node_t struct directly in this one
            // but there is potentially a port_table size difference so
            // do not replace it with node_t struct.
            struct __attribute__((__packed__))
                uint16_t node_id : 12;  // Node id
                uint16_t certified : 4; // True if the node have a certificate
            uint16_t port_table[(MAX_ALIAS_SIZE + 2 + 2 - 2) / 2]; // Node link table
        uint8_t unmap_data[MAX_ALIAS_SIZE + 2 + 2];
} routing_table_t;

container entry mode

This mode allows routing_table to contain:

  • id: container's unique id
  • type: container's type
  • alias: container's alias

For more information, please refer to the containers page of this documentation.

Node entry mode

This mode gives physical information of your devices.

The node_id is the unique number that you can use to identify each one of your nodes. At the beginning (or when a reset detection is perfomed), all node IDs are set to 0. When the RoutingTB_DetectContainers API is called, Luos assigns a unique ID to nodes and containers in your system topology.

The certified Luos node can be certified for your system by including Luos licencing number in your product (feature in progress).

The port_table allows sharing of topological information of your network. Each element of this table corresponds to a physical Luos port of the node and indicates which node is connected to it by sharing a node's id.

Here is an example:

As shown on this image, elements of the port_table indicate the first or last container id of the connected node through a given port.

Specific values taken by port_table:

  • 0: this port is waiting to discover who is connected with. You should never see this value.
  • 0x0FFF: this port is not connected to any other Node.

Note: Routing tables can be easily displayed using Pyluos through a USB gate. Please refer to the Pyluos routing table section for more information.

Search tools

The routing table library provides the following search tools to find containers and nodes' information into a Luos network:

Find a container's id from its aliasRoutingTB_IDFromAlias(char* alias);uint16_t
Find a container's id from its type (return the first of the list)RoutingTB_IDFromType(luos_type_t type);uint16_t
Find a container's id from a containerRoutingTB_IDFromContainer(container_t *container);uint16_t
Find a container's alias from its id (return the first of the list)RoutingTB_AliasFromId(uint16_t id);char*
Find a container's type from its idRoutingTB_TypeFromID(uint16_t id);container_type_t
Find a container's type from its aliasRoutingTB_TypeFromAlias(char* alias);container_type_t
Find a container's string from its type (return the first of the list)RoutingTB_StringFromType(luos_type_t type);char*
Test if a container's type is a sensorRoutingTB_ContainerIsSensor(container_type_t type);uint8_t
Get the number of nodes in a Luos networkRoutingTB_GetNodeNB(void);uint16_t
Get a node's idRoutingTB_GetNodeID(unsigned short index);uint16_t

Management tools

Here are the management tools provided by the routing table library:

Compute the rooting tableRoutingTB_ComputeRoutingTableEntryNB(void);void
Detect the containers in a Luos networkRoutingTB_DetectContainers(container_t* container);void
Convert a node to a routing table entryRoutingTB_ConvertNodeToRoutingTable(routing_table_t *entry, node_t *node);void
Convert a container to a routing table entryRoutingTB_ConvertContainerToRoutingTable(routing_table_t* entry, container_t* container);void
Remove an entry in the routing table (by id)RoutingTB_RemoveOnRoutingTable(uint16_t id);void
Erase routing tableRoutingTB_Erase(void);void
Get the routing tableRoutingTB_Get(void);routing_table_t*
Get the last container in a Luos networkRoutingTB_GetLastContainer(void);uint16_t
Get the last entry in a Luos networkRoutingTB_GetLastEntry(void);uint16_t
Get the last node in a Luos networkRoutingTB_GetLastNode(void);uint16_t*
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