Service Discovery Action Frames

5.2.7.1 WFD Service Discovery

If WFD Service Discovery is supported, the WFD Device shall make use of the Service Discovery action frames defined in [7], except as noted in the following.

A WFD Device shall set the following fields within a Service Discovery Action Frame;

• OI field to the WFA OUI 0x50 6F 9A

• OUI subtype field to 0x09

• Service protocol type to 0x04.

The query data field of the WFD Service Discovery Query frame transmitted by a WFD Device shall be comprised of a single Service Request TLV for each requested device role with each indicating information for which the requestor seeks response data. For example, if a WFD Device uses a Service Discovery Action Frame to query information from a WFD Device which can function as a WFD Source and a WFD Sink, then the WFD Device can include two TLVs within the same action frame. The query data format encapsulated in the Query Data field in Service TLV field for a WFD Service Discovery Query is specified in Table 5-45. The allowed sets of requested information for a WFD Service Discovery Query frame are identified in Table 5-3.

Field Size

0x02: Secondary Sink

0x03: dual role of WFD Source and Primary Sink List of WFD

subelement IDs

Variable Requested WFD Subelements as an array of subelement IDs as per Table 5-3

Table 5-45 : Query data format for a WFD Service Discovery Query frame

The response data field of the Service Discovery Response frame transmitted by a WFD Device in response to a received Service Discovery Query frame shall be comprised of the requested Service Response TLVs, where each contains response data specifying the respective information subelements. The Service Transaction ID in the Service Response TLV shall match the Service Transaction ID in the Query Data for the specific device role.

Subelements to be included in the WFD IE for WFD Service Discovery action frames are listed in Table 5-46.

Subelement name Requirements

WFD Device Information If requested, the WFD Device Information subelement shall be present in the WFD IE in the WFD Service Discovery Response action frames it transmits.

Associated BSSID If requested and if the responding WFD Device is associated with an infrastructure AP or a GO and the WFD Device sets its PC bit to 0b1 in the WFD Device Information subelement, the WFD Device shall include the Associated BSSID subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

WFD Audio Formats If requested and if the responding WFD Device has audio capability, the WFD Device shall include the WFD Audio Formats subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

WFD Video Formats If requested and if the responding WFD Device has video capability, the WFD Device shall include the WFD Video Formats subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

WFD 3D Video Formats If requested and if the responding WFD Device has 3D video capability over WFD, the WFD Device shall include the WFD Video Formats subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

WFD Content Protection If requested and if the responding WFD Device supports Content Protection, the WFD Device shall include the WFD Content Protection subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

Coupled Sink Information If requested and if the responding WFD Sink supports Coupled Sink Operation, the WFD Device shall include the Coupled Sink Information subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

WFD Extended Capability If requested and if the responding WFD Device supports at least one of UIBC, Remote I2C Read/Write, Preferred Display mode and TDLS as a preferred connectivity scheme for WFD, the WFD Device shall include the WFD Extended Capability subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

Local IP Address If requested and if the responding WFD Device supports TDLS as a preferred connectivity scheme for WFD, the WFD Device shall include the Local IP address subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

WFD Session Information If requested and if the WFD Device is acting as a GO and has WFD Session(s) with other WFD Device(s), the WFD Device shall include the WFD Session information subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

Alternate MAC Address If requested and if the responding WFD Device supports TDLS as a preferred connectivity scheme for WFD, the WFD Device shall include the Alternate MAC Address subelement in the WFD IE in the WFD Service Discovery Response action frames it transmits.

Table 5-46 : Information Subelement in WFD IE at WFD Service Discovery Response

6 RTSP Based WFD Control Plane

This chapter defines the methods and messages that are used to establish, maintain, manage and teardown WFD Sessions.

A WFD Sink shall establish a layer 3 connection with a WFD Source before beginning WFD Session establishment and management. WFD Session management shall use RTSP [23] (RFC2326) over TCP as the communication protocol. The WFD Sink shall use the WFD Session management Control Port value (contained in the WFD IE) for all session management communication.

Since the RTSP specification [23] does not allow an RTSP server to initiate the SETUP, PLAY, PAUSE or TEARDOWN methods, this Specification uses SET_PARAMETER messages with a wfd-trigger-method parameter to enable the RTSP server to trigger the client into initiating control operations while still maintaining compliance with [23].