RE: Relay behaviour of mesh when buffer is full

Omkar Kulkarni — Wed, 20 Feb 2019 15:40:59 GMT

Hi,

Your observation is correct, mesh stack will add network PDU to network cache even if it fails to relay. This is something that could be improved in the mesh stack.

About other points:

1. Tx path simply won't accept any new packets until there is sufficient space available in the buffer. It will not drop already queued packets.

2. Packet buffers for originator and relay roles are different. Their sizes can be controlled by these settings: `CORE_TX_QUEUE_BUFFER_SIZE_ORIGINATOR`, `CORE_TX_QUEUE_BUFFER_SIZE_RELAY`.

3. Mesh stack will not check for the number of packets getting originated. The recommendation specified in the mesh specification is not an enforced shall statement. It is mainly directed towards end application developers and network administrators to not configure (many) nodes in their network such that they will generate a lot of traffic. However, in a certain application specific scenario, there could a reasonable requirement to do so for a short period of time without harming a network at large (for example, health model publishing faults at a higher cadence, while other models on other elements on the same node are also publishing their own messages, leading to a higher number of messages being published by a node until the fault is resolved.) Applying a stack level constraint will kill the possibility of momentary higher traffic for valid reasons.