A method for locating loss of a service packet, the method being applied to a Virtual extensible Local Area Network Tunnel End Point, VTEP, comprising: obtaining a simulation packet for simulating a service forwarding path for routing a service packet from the VTEP to another VTEP; wherein the service packet is a packet that was sent from a first Virtual Machine, VM, accessing the VTEP, was routed through the service forwarding path by the VTEP, and did not reach a second VM accessing the another VTEP, and packet character parameters of the simulation packet are identical to packet character parameters of the service packet; calculating an outer User Datagram Protocol, UDP, source port number based on the packet character parameters of the simulation packet according to a local chip forwarding logic; performing a Virtual extensible Local Area Network, VXLAN, encapsulation for the simulation packet based on the outer UDP source port number and a VXLAN tunnel identification which is stored in a local register entry; wherein, the local register entry matches with the simulation packet; a value of the first reserve field of a VXLAN header of the simulation packet is a set value; forwarding the simulation packet with the VXLAN encapsulation through the VXLAN tunnel corresponding to the VXLAN tunnel identification, so that each device on the service forwarding path which has received the simulation packet with the VXLAN encapsulation sends a packet loss locating parameter to a packet loss locating device, which determines a packet loss location on the service forwarding path based on a device identity in the last received packet loss locating parameter. obtaining a simulation packet for simulating a service forwarding path for routing a service packet from the VTEP to another VTEP; wherein the service packet is a packet that was sent from a first Virtual Machine, VM, accessing the VTEP, was routed through the service forwarding path by the VTEP, and did not reach a second VM accessing the another VTEP, and packet character parameters of the simulation packet are identical to packet character parameters of the service packet; calculating an outer User Datagram Protocol, UDP, source port number based on the packet character parameters of the simulation packet according to a local chip forwarding logic; performing a Virtual extensible Local Area Network, VXLAN, encapsulation for the simulation packet based on the outer UDP source port number and a VXLAN tunnel identification which is stored in a local register entry; wherein, the local register entry matches with the simulation packet; a value of the first reserve field of a VXLAN header of the simulation packet is a set value; forwarding the simulation packet with the VXLAN encapsulation through the VXLAN tunnel corresponding to the VXLAN tunnel identification, so that each device on the service forwarding path which has received the simulation packet with the VXLAN encapsulation sends a packet loss locating parameter to a packet loss locating device, which determines a packet loss location on the service forwarding path based on a device identity in the last received packet loss locating parameter. <EOS>