Data center network, flow balancing method thereof and controller

The invention is suitable for the field of communication, and provides a data center network, a flow balancing method thereof and a controller. The data center network includes: a controller configures one or more of COS, TOS and TTL as a hash factor(s) for ECMP routing of network equipment; flow of Hypervisor or vSw in the network equipment and a physical server is collected, and when an interconnection link failure between network equipment is determined or occurrence of congestion is determined according to flow, a packaging control strategy is sent to the Hypervisor or the vSw; the physical server determines the value(s) of one or more fields of COS, TOS and TTL fields of an NVO3 message in a source physical server; and the network equipment receives configuration of the controller, and uses one or more of the COS, TOS and TTL configured in the NVO3 message as the hash factors to perform ECMP routing. The data center network in the invention realizes an optimal utilization rate of a physical network.