Low latency, low loss, and scalable throughput congestion signaling from lower protocol layer to higher protocol layer of network stack

A network device, comprising:

• a higher protocol layer circuit;
• and
• a lower protocol layer circuit coupled to the higher protocol layer circuit, wherein
• the lower protocol layer circuit is configured to:
• maintain a receive buffer to buffer for one or more upstream data packets of at least one upstream Low Latency, Low Loss, and Scalable throughput (L4S) data flow;
• detect a congestion in the receive buffer;
• and
• transmit, to the higher protocol layer circuit, a congestion signal configured to indicate the detected congestion.

A method, comprising:

• in a network device that comprises a higher protocol layer circuit and a lower protocol layer circuit:
• maintaining, by the lower protocol layer circuit, a Low Latency, Low Loss, and Scalable throughput (L4S) data queue, wherein the L4S data queue buffers one or more L4S data packets of at least one L4S data flow for transmission;
• detecting, by the lower protocol layer circuit, a congestion in the L4S data queue;
• and
• transmitting, by the lower protocol layer circuit, a congestion signal to the higher protocol layer circuit, wherein the congestion signal indicates the detected congestion.