Configuring switches in a network fabric

A computer readable medium storing specific computer-executable instructions that, when executed by a processor, cause a computer system for:

• providing a network fabric including a first plurality of switches and a plurality of blocks of switches, the first plurality of switches communicatively coupling a plurality of host machines to the plurality of blocks of switches, wherein each block of switches of the plurality of blocks of switches includes a second plurality of switches arranged in a hierarchical manner including a first layer of switches that are communicatively coupled to a second layer of switches;
• configuring a routing policy for each switch included in the first layer of switches, wherein the switch included in the first layer of switches comprises a first set of ports that are communicatively coupled to the first plurality of switches and a second set of ports that are communicatively coupled to the second layer of switches, wherein the routing policy causes traffic received on a first port included in the first set of ports to be always forwarded on a second port included in the second set of ports of the switch;
• and
• responsive to a first GPU included in a first host machine transmitting a packet intended for a second GPU included in a second host machine, routing the packet via the network fabric based on the configuring.

A computing device comprising:

• a processor;
• and
• a memory including instructions that, when executed with the processor, cause the computing device to, at least:
• provide a network fabric including a first plurality of switches and a plurality of blocks of switches, the first plurality of switches communicatively coupling a plurality of host machines to the plurality of blocks of switches, wherein each block of switches of the plurality of blocks of switches includes a second plurality of switches arranged in a hierarchical manner including a first layer of switches that are communicatively coupled to a second layer of switches;
• configure a routing policy for each switch included in the first layer of switches, wherein the switch included in the first layer of switches comprises a first set of ports that are communicatively coupled to the first plurality of switches and a second set of ports that are communicatively coupled to the second layer of switches, wherein the routing policy causes traffic received on a first port included in the first set of ports to be always forwarded on a second port included in the second set of ports of the switch;
• and
• responsive to a first GPU included in a first host machine transmitting a packet intended for a second GPU included in a second host machine, route the packet via the network fabric based on the routing policy configured for switches included in the first layer of switches.