A packet processing method performed by a first network device in an Ethernet virtual private network, EVPN, the EVPN comprising the first network device and a second network device, and the method comprises the steps of: • receiving a virtual extensible local area network, VXLAN, packet from the second network device, ∘ wherein the VXLAN packet comprises a path identifier, a service packet, and a flag bit, ∘ wherein the path identifier indicates a path from the first network device to a virtualized network function, VNF, device through an interface processing unit, IPU, the first network device is connected to the IPU, the service packet comprises a destination Internet Protocol, IP, address, the destination IP address is an IP address of the VNF device, and the IPU is connected to the VNF device, ∘ wherein the flag bit is used to indicate that the VXLAN packet comprises the path identifier; • determining based on the flag bit that the VXLAN packet comprises the path identifier; • in response to the determination that the VXLAN packet comprises the path identifier, determining (step 304), based on the path identifier and based on equal-cost multipath, ECMP, routing information, first routing information contained in the ECMP routing information, wherein the first routing information indicates the path from the first network device to the VNF device through the IPU; and • forwarding the service packet to the VNF device via the IPU based on the first routing information and the destination IP address. • receiving a virtual extensible local area network, VXLAN, packet from the second network device, ∘ wherein the VXLAN packet comprises a path identifier, a service packet, and a flag bit, ∘ wherein the path identifier indicates a path from the first network device to a virtualized network function, VNF, device through an interface processing unit, IPU, the first network device is connected to the IPU, the service packet comprises a destination Internet Protocol, IP, address, the destination IP address is an IP address of the VNF device, and the IPU is connected to the VNF device, ∘ wherein the flag bit is used to indicate that the VXLAN packet comprises the path identifier; ∘ wherein the VXLAN packet comprises a path identifier, a service packet, and a flag bit, ∘ wherein the path identifier indicates a path from the first network device to a virtualized network function, VNF, device through an interface processing unit, IPU, the first network device is connected to the IPU, the service packet comprises a destination Internet Protocol, IP, address, the destination IP address is an IP address of the VNF device, and the IPU is connected to the VNF device, ∘ wherein the flag bit is used to indicate that the VXLAN packet comprises the path identifier; • determining based on the flag bit that the VXLAN packet comprises the path identifier; • in response to the determination that the VXLAN packet comprises the path identifier, determining (step 304), based on the path identifier and based on equal-cost multipath, ECMP, routing information, first routing information contained in the ECMP routing information, wherein the first routing information indicates the path from the first network device to the VNF device through the IPU; and • forwarding the service packet to the VNF device via the IPU based on the first routing information and the destination IP address.