Espressif ESP32-S2 Programming Manual page 1323

Chapter 4. API Guides
preferred parent node due it having fewer downstream connections (fewer child nodes) compared to node B.
Panel B of the illustration above demonstrates the case where the root node is within range of the idle node G. In
other words, the root node' s beacon frames are above the RSSI threshold when received by node G. The root node is
always the shallowest node in an ESP-WIFI-MESH network hence is always the preferred parent node given multiple
parent node candidates.
Note: Users may also define their own algorithm for selecting a preferred parent node, or force a node to only
connect with a specific parent node (see the
Routing Tables
Each node within an ESP-WIFI-MESH network will maintain its individual routing table used to correctly route ESP-
WIFI-MESH packets (see
node will consist of the MAC addresses of all nodes within the particular node's subnetwork (including the
MAC address of the particular node itself). Each routing table is internally partitioned into multiple subtables with
each subtable corresponding to the subnetwork of each child node.
Using the diagram above as an example, the routing table of node B would consist of the MAC addresses of nodes B
to I (i.e. equivalent to the subnetwork of node B). Node B's routing table is internally partitioned into two subtables
containing of nodes C to F and nodes G to I (i.e. equivalent to the subnetworks of nodes C and G respectively).
ESP-WIFI-MESH utilizes routing tables to determine whether an ESP-WIFI-MESH packet should be for-
warded upstream or downstream based on the following rules.
1. If the packet's destination MAC address is within the current node's routing table and is not the current node,
select the subtable that contains the destination MAC address and forward the data packet downstream to the child
node corresponding to the subtable.
2. If the destination MAC address is not within the current node's routing table, forward the data packet upstream
to the current node's parent node. Doing so repeatedly will result in the packet arriving at the root node where the
routing table should contain all nodes within the network.
Note: Users can call
ble, or esp_mesh_get_routing_table_size()
Espressif Systems
Mesh Manual Networking
ESP-WIFI-MESH Packet) to the correct destination node. The routing table of a particular
Fig. 9: ESP-WIFI-MESH Routing Tables Example
esp_mesh_get_routing_table()
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Example).
to obtain a node's routing ta-
to obtain the size of a node's routing table.
1312 Release v4.4