Deadlock avoidance in leaf-spine networks

One or more non-transitory computer readable storage media encoded with instructions that, when executed by a processor of a leaf switch in a network, cause the processor to:

• monitor traffic of a plurality of packets in the network, the network including a first spine switch connected to the leaf switch and a second spine switch connected to the leaf switch;
• mark a packet of the plurality of packets with an identifier associated with an inbound uplink port of the leaf switch when the packet is received from one of the first spine switch and the second spine switch;
• detect a valley routing condition in the network when the packet marked with the identifier is being routed to an outbound uplink port of the leaf switch to be transmitted to one of the first spine switch and the second spine switch;
• and
• upon detecting the valley routing condition in the network, drop packets associated with a no-drop class of service, at the leaf switch.

An apparatus comprising:

• a plurality of ports configured to receive inbound packets and to send outbound packets in a network, the network including a first spine switch connected to one of the plurality of network ports and a second spine switch connected to one of the plurality of ports;
• a processor coupled to the plurality of network ports, wherein the processor is configured to:
• mark a packet with an identifier associated with an inbound uplink port of the plurality of network ports when the packet is received from one of the first spine switch and the second spine switch;
• detect a valley routing condition in the network when the packet marked with the identifier is being routed to an outbound uplink port to be transmitted to one of the first spine switch and the second spine switch;
• and
• upon detection of the valley routing condition in the network, drop packets associated with a no-drop class of service.