A method of transmitting packets between virtual extensible local area network tunnel end point, VTEP, devices of different domains, each domain (DC1; DC2) comprises an egress VTEP device (10; 20) and at least one local VTEP device (10a-c; 20d-f), wherein a plurality of intra-domain virtual extensible local area network, VXLAN, tunnels are established between the egress VTEP device and each of the at least one local VTEP device, the method comprising: receiving, by an egress VXLAN tunnel end point, VTEP, device, a first packet from one of the at least one local VTEP device through an intra-domain VXLAN tunnel between the egress VTEP device and the one of the at least one local VTEP device; determining, by the egress VTEP device, a first tunnel interface by querying a media access control, MAC, address table according to a destination MAC address of the first packet; acquiring, by the egress VTEP device, a second VXLAN identifier by querying a stored inter-domain VXLAN identifier mapping relationship according to a first VXLAN identifier carried in the first packet; replacing, by the egress VTEP device, the first VXLAN identifier carried in the first packet with the second VXLAN identifier; sending, by the egress VTEP device, the first packet carrying the second VXLAN identifier to an egress VTEP device on an opposite end through an inter-domain VXLAN tunnel corresponding to the first tunnel interface; receiving, by the egress VTEP device, a second packet from the egress VTEP device on the opposite end, through an inter-domain VXLAN tunnel; determining, by the egress VTEP device, a second tunnel interface by querying the MAC address table according to a destination MAC address of the second packet; sending, by the egress VTEP device, the second packet to one of the at least one local VTEP device through an intra-domain VXLAN tunnel corresponding to the second tunnel interface; wherein the egress VTEP device and the local VTEP device belongs to a same domain, and the intra-domain VXLAN tunnel is a VXLAN tunnel established between the egress VTEP device and the local VTEP device; and the egress VTEP device and the egress VTEP device on the opposite end belongs to different domains, and the inter-domain VXLAN tunnel is a VXLAN tunnel established between the egress VTEP device and the egress VTEP device on the opposite end. receiving, by an egress VXLAN tunnel end point, VTEP, device, a first packet from one of the at least one local VTEP device through an intra-domain VXLAN tunnel between the egress VTEP device and the one of the at least one local VTEP device; determining, by the egress VTEP device, a first tunnel interface by querying a media access control, MAC, address table according to a destination MAC address of the first packet; acquiring, by the egress VTEP device, a second VXLAN identifier by querying a stored inter-domain VXLAN identifier mapping relationship according to a first VXLAN identifier carried in the first packet; replacing, by the egress VTEP device, the first VXLAN identifier carried in the first packet with the second VXLAN identifier; sending, by the egress VTEP device, the first packet carrying the second VXLAN identifier to an egress VTEP device on an opposite end through an inter-domain VXLAN tunnel corresponding to the first tunnel interface; receiving, by the egress VTEP device, a second packet from the egress VTEP device on the opposite end, through an inter-domain VXLAN tunnel; determining, by the egress VTEP device, a second tunnel interface by querying the MAC address table according to a destination MAC address of the second packet; sending, by the egress VTEP device, the second packet to one of the at least one local VTEP device through an intra-domain VXLAN tunnel corresponding to the second tunnel interface; wherein the egress VTEP device and the local VTEP device belongs to a same domain, and the intra-domain VXLAN tunnel is a VXLAN tunnel established between the egress VTEP device and the local VTEP device; and the egress VTEP device and the egress VTEP device on the opposite end belongs to different domains, and the inter-domain VXLAN tunnel is a VXLAN tunnel established between the egress VTEP device and the egress VTEP device on the opposite end.