A method for measuring network performance parameters, comprising: receiving (02, 03), by a first device for measuring network performance parameters, at least two extended bidirectional forwarding detection, BFD, packets transmitted by a second device for measuring network performance parameters, said extended BFD packets comprising a packet loss monitoring Type-Length-Value, TLV; calculating network performance parameters according to the packet loss monitoring TLV in the received extended BFD packets; wherein a value field of the packet loss monitoring TLV comprises a transmit sequence number and a transmit count, and the transmit count is the number of preset type packets that have been transmitted when an extended BFD packet of the at least two BFD packets is transmitted by the second device; and wherein the calculating the network performance parameters comprises packet loss monitoring near-end calculation, and the packet loss monitoring near-end calculation is: a near-end packet loss Packet Loss[near-end]= |TxPacketCounter_L -TxPacketCoun ter_L |- |RxPacketCounterL [BFDl]-RxPacketCounterL |, wherein TxPacketCounter_L indicates the transmit count of the received extended BFD packet with transmit sequence number BFD1, and TxPacketCounter_L indicates the transmit count of the received extended BFD packet with transmit sequence number BFD2; and RxPacketCounterL indicates the number of preset type packets that have been received by the first device from the second device for measuring network performance parameters when the extended BFD packet with transmit sequence number BFD1 is received, and RxPacketCounterL indicates the number of preset type packets that have been received by the first device from the second device for measuring network performance parameters when the extended BFD packet with transmit sequence number BFD2 is received; wherein a field of the extended BFD packets is set to mark that the extended BFD packets comprise the packet loss monitoring TLV, said field being: a Poll field of the respective extended BFD packet; or an Authentication Present field of the respective extended BFD packet; or a reserved field of a Diagnostic (Diag) part in the respective extended BFD packet. receiving (02, 03), by a first device for measuring network performance parameters, at least two extended bidirectional forwarding detection, BFD, packets transmitted by a second device for measuring network performance parameters, said extended BFD packets comprising a packet loss monitoring Type-Length-Value, TLV; calculating network performance parameters according to the packet loss monitoring TLV in the received extended BFD packets; wherein a value field of the packet loss monitoring TLV comprises a transmit sequence number and a transmit count, and the transmit count is the number of preset type packets that have been transmitted when an extended BFD packet of the at least two BFD packets is transmitted by the second device; and wherein the calculating the network performance parameters comprises packet loss monitoring near-end calculation, and the packet loss monitoring near-end calculation is: a near-end packet loss Packet Loss[near-end]= |TxPacketCounter_L -TxPacketCoun ter_L |- |RxPacketCounterL [BFDl]-RxPacketCounterL |, wherein TxPacketCounter_L indicates the transmit count of the received extended BFD packet with transmit sequence number BFD1, and TxPacketCounter_L indicates the transmit count of the received extended BFD packet with transmit sequence number BFD2; and RxPacketCounterL indicates the number of preset type packets that have been received by the first device from the second device for measuring network performance parameters when the extended BFD packet with transmit sequence number BFD1 is received, and RxPacketCounterL indicates the number of preset type packets that have been received by the first device from the second device for measuring network performance parameters when the extended BFD packet with transmit sequence number BFD2 is received; a near-end packet loss Packet Loss[near-end]= |TxPacketCounter_L -TxPacketCoun ter_L |- |RxPacketCounterL [BFDl]-RxPacketCounterL |, wherein TxPacketCounter_L indicates the transmit count of the received extended BFD packet with transmit sequence number BFD1, and TxPacketCounter_L indicates the transmit count of the received extended BFD packet with transmit sequence number BFD2; and RxPacketCounterL indicates the number of preset type packets that have been received by the first device from the second device for measuring network performance parameters when the extended BFD packet with transmit sequence number BFD1 is received, and RxPacketCounterL indicates the number of preset type packets that have been received by the first device from the second device for measuring network performance parameters when the extended BFD packet with transmit sequence number BFD2 is received; wherein a field of the extended BFD packets is set to mark that the extended BFD packets comprise the packet loss monitoring TLV, said field being: a Poll field of the respective extended BFD packet; or an Authentication Present field of the respective extended BFD packet; or a Poll field of the respective extended BFD packet; or an Authentication Present field of the respective extended BFD packet; or a reserved field of a Diagnostic (Diag) part in the respective extended BFD packet.