Which statement about the Lightweight Access Point Protocol （LWAPP） is true？（）

A. A Voice over IP （VoIP） packet consists of the voice payload， IP header， TCP header， RTP header， and  Layer 2 link header.
B. The voice carrier stream uses H323 to set up， maintain， and tear down call endpoints.
C. Call control signaling uses Real-Time Transport Protocol （RTP） packets that contain actual voice  samples.
D. The sum of bandwidth necessary for each major application， including voice， video， and data， should not exceed 75 percent of the total available bandwidth for each link.

A. The CoS value is trusted for 802.1p or 802.1q tagged traffic.
B. The voice VLAN feature is disabled by default.
C. The IP phone accepts the priority of all tagged and untagged traffic and sets the CoS value to 4.
D. When the voice VLAN feature is enabled， all untagged traffic is sent according to the default CoS priority of the port.
E. PortFast is automatically disabled when a voice VLAN is configured.
F. The default CoS value for incoming traffic is set to 0.

A. A lightweight AP receives control and configuration from a WLAN controller to which it is associated.
B. A WLAN client that is operating in half-duplex mode will delay all clients in that WLAN
C. A dhoc mode allows mobile clients to connect directly without an intermediate AP
D. Another term for infrastructure mode is independent service set （IBSS）
E. The Aironet 1230 access point is an example of an access point that operates solely as a lightweight  access point.
F. WLANs are designed to share the medium and can easily handle an increased demand of channel  contention.