2.1 KiB
WIP
Data Link Layer
This component represents the data link layer. It will handle board to board communication (abstracting away the RMT specific details of transmitting physical raw bits over wires).
Frame Definitions
See ./include/Frames.h for frame definitions.
There will be two types of frames: Control and Generic.
Control frames will contain all control information (eg. Spinning a DC motor, moving a servo to a particular angle, sensor information). These frames will have a limit of 256B of data size with a total packet size of 41B. These frames will not be fragmented.
Generic frames will contain all other information. They will have a max data size of 16MiB if fragmented (max 2**16 fragments). Each fragment will still maintain a max 256B data size.
To differentiate between the two frames, the type field in both frames will be compared against. If the MSB is set to 1, it will be determined to be a control packet.
Routing Information Protocol (RIP) Table
See ./include/Tables.h for table definitions. See DataLinkRIP.cpp for function definitions.
It handles all known (advertised) boards on the same network of ESP32-S3 boards. It will broadcast its stored routing table to its neighbours roughly every 30 seconds or upon receiving a routing table from its neighbours. All routes on a routing table will expire after 180 seconds, unless refreshed/updated/re-advertised by that respective board. The routing table itself will be used to route frames using the path with the least number of hops (known locally).
Frame Management
See DataLinkFrames.cpp for more information.
It handles generic frame fragmentation, user handling of receiving received frames (stored in a queue, per channel), and a thread to handle polling the available channels for receiving.
Send Frames Scheduler
See DataLinkScheduler.cpp for more information.
It handles all TX frames passed from the user and schedules them to be sent. The frames are stored in a priority queue (per channel), where Control frames has a higher priority than Generic frames (generally). The actual scheduler algorithm can be found in Scheduler.h.