US 2026/0303534 A1 · INCAST CONGESTION MANAGEMENT

Abstract

Devices, systems, methods, and processes for incast congestion management are described herein. Typically, in a Packet Sequence Number (PSN) based Remote Direct Memory Access (RDMA) network, Priority Flow Control (PFC) is asserted upstream when an incast congestion event occurs, which can victimize unrelated flows. Thus, instead of asserting PFC, a switch in the PSN based RDMA network detects an incast congestion event and directly notifies one or more Reliable Connection (RC) Queue Pairs (QPs) of various sending devices, associated with the incast congestion event using Receiver Not Ready (RNR) negative acknowledgements (NACKs). These RNR NACKs are associated with unique pause time-periods. The associated RC QPs receive the RNR NACKs and pause packet transmission. The associated RC QPs resume packet transmission upon expiration of corresponding pause time-periods. Thus, the packet transmission from the contributing RC QPs is spaced out, avoiding all packets reaching a switch output port at the same time.

Claims20

Dependent claims

A device, comprising:

a processor;
a network interface controller configured to provide access to a network;
and
a memory communicatively coupled to the processor, wherein the memory comprises a congestion management logic that is configured to:
detect an incast congestion event;
generate a negative acknowledgement for a Reliable Connection (RC) Queue Pair (QP) associated with the detected incast congestion event;
transmit the negative acknowledgement to a network device associated with the RC QP;
utilize a Send Queue (SQ) of each identified RC QP to pause packet transmission until an expiration of a pause time-period indicated in a corresponding RNR NACK;
and
determine one or more first packets among a plurality of packets that are to be dropped due to the incast congestion event.

7 more elements

Dependencies are inferred from the claim text.

Incast congestion management

Life of this patent

Incast congestion management

Life of this patent

Abstract

Claims20