Packet order recovery in a programmable edge switch in a data center network

A method comprising:

• in an edge switch with one or more programmable Application Specific Integrated Circuits (ASICs) configured to implement programmable functions, receiving incoming packets associated with flows in a data center network where the flows are forwarded on a per-packet basis, wherein at a particular time at a particular switch port the flows include a number of active concurrent flows;
• maintaining a state table that includes a state of the flows and of received incoming packets, wherein the state table includes a corresponding state for a subset of all flows through the edge switch and entries in the state table are only kept for a refresh time window that has a value where the number of active concurrent flows is orders of magnitude higher than a number of flows in the state table, and wherein the state table is stored in registers of the programmable ASICs and managed via the programmable functions;
• and
• dequeuing the received incoming packets based on one or more packet dequeue conditions and the state table, including re-ordering of the received incoming packets in a correct order based on the state table such that the re-ordering is performed at the edge switch as opposed to a server, wherein the re-ordering comprises dequeuing a packet of the received incoming packets within the edge switch before being transmitted to the server when a sequence number of the packet indicates a correct order and, when the sequence number of the packet indicates an incorrect order, maintaining a payload of the packet and recirculating a header of the packet.

A data center network comprising:

• a plurality of switches communicatively coupled to a plurality of servers,
• wherein packets associated with flows in the data center network are forwarded on a per-packet basis, wherein at a particular time at a particular switch port the flows include a number of active concurrent flows;, and
• wherein each of the plurality of switches include one or more programmable Application Specific Integrated Circuits (ASICs) configured to implement programmable functions, wherein the one or more programmable ASICs include are configured to
• maintain a state table that includes a state of the flows and of received incoming packets, wherein the state table includes a corresponding state for a subset of all flows through a particular edge switch of the plurality of switches and entries in the state table are only kept for a refresh time window that has a value where the number of active concurrent flows is orders of magnitude higher than a number of flows in the state table, and wherein the state table is stored in registers of the programmable ASICs and managed via the programmable functions, and
• dequeue the received incoming packets based on one or more packet dequeue conditions and the state table, including re-ordering of the received incoming packets in a correct order based on the state table such that the re-ordering is performed at the particular edge switch as opposed to a server, wherein the re-ordering comprises dequeuing a packet of the received incoming packets within the particular edge switch before being transmitted to the server when a sequence number of the packet indicates a correct order and, when the sequence number of the packet indicates an incorrect order, maintaining a payload of the packet and recirculating a header of the packet.