The embodiment of the invention discloses a
data transmission method and device, and a network
system. The network
system comprises a switch, at least one computing node, and at least one network node, wherein the initial status of each
virtual router configured in each network node is an active status, and at least one
virtual machine is configured in each computing node. The method applied to the switch of the network
system comprises the following steps: receiving a target data packet sent by a first host, wherein the target data packet carries an
IP address of the first host and a first target
IP address; according to the
IP address of the first host or the first target IP address, determining a first
virtual router from the virtual routers in the active status; and sending the targetdata packet to the first
virtual router, so that the first virtual
router sends the target data packet to a target
virtual machine based on the first target IP address, wherein the target
virtual machine is determined by the first virtual
router according to the first target IP address. The
data transmission method and device and the network system provided by the embodiment of the invention havethe
advantage that
continuous data transmission can be guaranteed.