Fast data center congestion response

One or more tangible, non-transitory computer-readable storage mediums having stored thereon instructions to instruct a computing apparatus to:

• compute a bandwidth consumption of a flow associated with a packet received from a source host on an ingress port and assigned to a destination host communicatively coupled to a first egress port;
• determine based on the computed bandwidth consumption that the flow is congested;
• extract a flow identifier of the flow;
• calculate a quantitative flow throttle value for the flow;
• and
• build a packet configured to instruct the source host to throttle the flow;
• and
• send the packet to the source host via a second egress port.

A method of providing fast congestion response, comprising:

• computing a bandwidth consumption of a flow associated with a packet received from a source host on an ingress port and assigned to a destination host communicatively coupled to a first egress port;
• determining based on the computed bandwidth consumption that the flow is congested;
• extracting a flow identifier of the flow;
• calculating a quantitative flow throttle value for the flow;
• and
• building a packet configured to instruct the source host to throttle the flow;
• and
• sending the packet to the source host via a second egress port.

A congestion notification generator (CNG) circuit to:

• compute bandwidth consumption of a flow associated with a packet received from a source host on an ingress port and assigned to a destination host communicatively coupled to a first egress port, and determine based on the computed bandwidth consumption that the flow is congested;
• extract a flow identifier of the flow;
• calculate a quantitative flow throttle value for the flow;
• and
• build a congestion notification packet configured to instruct the source host to throttle the flow.