Method and apparatus for processing multicast frame

1. A method of processing a multicast frame in a wireless local area network system, the method comprising: transmitting a request message for requesting a Directed Multicast Service (DMS) in which at least one multicast frame is transmitted as at least one unicast frame by an Access Point (AP); receiving a response message from the AP in response to the request message; receiving the at least one multicast frame from the AP, the at least one multicast frame being transmitted as the at least one unicast frame, wherein the request message comprises a DMS descriptor list field comprising a Transmission Class (TCLAS) element field and a Transmission Specification (TSPEC) element field, wherein the TCLAS element field comprises a requested multicast group address for the DMS, wherein the TSPEC element field defines Quality of Service (QoS) expectations information for the DMS, and wherein the TSPEC element field comprises minimum data rate information for the DMS, mean data rate information for the DMS, and peak data rate information for the DMS; and terminating the DMS by receiving a termination message indicating a termination of the DMS from the AP, wherein the termination message includes a sequence control field, and the sequence control field indicates a sequence number of a last multicast frame transmitted as a unicast frame.

2. The method of claim 1 , wherein the at least one multicast frame satisfies the QoS expectations defined in the TSPEC element.

3. The method of claim 1 , further comprising: after the termination of the DMS, determining whether a received multicast frame is duplicated with the at least one multicast frame; and discarding the received multicast frame if the received multicast frame is duplicated with the at least one multicast frame.

4. A method of processing a multicast frame in a wireless local area network system, the method comprising:

transmitting a request message for requesting a Directed Multicast Service (DMS) in which at least one multicast frame is transmitted as at least one unicast frame by an Access Point (AP);

receiving a response message from the AP in response to the request message;

receiving the at least one multicast frame from the AP, the at least one multicast frame being transmitted as the at least one unicast frame,

wherein the request message comprises a DMS descriptor list field comprising a Transmission Class (TCLAS) element field and a Transmission Specification (TSPEC) element field,

wherein the TCLAS element field comprises a requested multicast group address for the DMS, and

wherein the TSPEC element field defines Quality of Service (QoS) expectations information for the DMS;

terminating the DMS by receiving a termination message indicating a termination of the DMS from the AP;

after the termination of the DMS, determining whether a received multicast frame is duplicated with the at least one multicast frame; and

discarding the received multicast frame if the received multicast frame is duplicated with the at least one multicast frame,

wherein the termination message includes a sequence control field, and the sequence control field indicates a sequence number of a last multicast frame transmitted as a unicast frame.

5. The method of claim 4 , wherein the step of determining whether the received multicast frame is duplicated is based on the sequence control field.

6. A wireless apparatus for processing a multicast frame in a wireless local area network system, the wireless apparatus comprising: a Radio Frequency (RF) unit configured to transmit and receive radio signals; and a processor operably coupled to the RF unit, and configured to: transmit a request message for requesting a Directed Multicast Service (DMS) in which at least one multicast frame is transmitted as at least one unicast frame by an Access Point (AP), receive a response message from the AP in response to the request message, receive the at least one multicast frame from the AP, the at least one multicast frame being transmitted as the at least one unicast frame, and terminate the DMS by receiving a termination message indicating a termination of the DMS from the AP, wherein the request message comprises a DMS descriptor list field comprising a Transmission Class (TCLAS) element field and a Transmission Specification (TSPEC) element field, wherein the TCLAS element field comprises a requested multicast group address for the DMS, wherein the TSPEC element field defines Quality of Service (QoS) expectations information for the DMS, wherein the TSPEC element includes minimum data rate information for the DMS, mean data rate information for the DMS, and peak data rate information for the DMS, and wherein the termination message includes a sequence control field, and the sequence control field indicates a sequence number of a last multicast frame transmitted as a unicast frame.

7. The wireless apparatus of claim 6 , wherein the at least one multicast frame satisfies the QoS expectations defined in the TSPEC element.