Which two statements are true? (Choose two.)

You just implemented a Layer 2 network that uses RSTP.
Which two statements are true? (Choose two.)

A.
All operational switch ports configured for edge mode will immediately transition to the forwarding state.

B.
All operational switch ports configured for full-duplex operation will function in point-to-point mode.

C.
You must manually specify the interfaces you want to operate in point-to-point mode.

D.
Edge ports automatically discard received BPDUs.

Explanation:
Rapid Spanning Tree Protocol

In 2001, the IEEE introduced Rapid Spanning Tree Protocol (RSTP) as 802.1w. RSTP provides significantly faster spanning tree convergence after a topology change, introducing new convergence behaviors and bridge port roles to do this. RSTP was designed to be backwards-compatible with standard STP.

While STP can take 30 to 50 seconds to respond to a topology change, RSTP is typically able to respond to changes within 3Hello times (default: 3 times 2 seconds) or within a few milliseconds of a physical link failure. The so-called Hello time is an important and configurable time interval that is used by RSTP for several purposes; its default value is 2 seconds.

Standard IEEE 802.1D-2004 incorporates RSTP and obsoletes the original STP standard.

RSTP adds new bridge port roles in order to speed convergence following a link failure.

RSTP bridge port roles:

* Root – A forwarding port that is the best port from Nonroot-bridge to Rootbridge
* Designated – A forwarding port for every LAN segment
* Alternate – An alternate path to the root bridge. This path is different than using the root port.
* Backup – A backup/redundant path to a segment where another bridge port already connects.
* Disabled – Not strictly part of STP, a network administrator can manually disable a port

Additional RSTP Operation Details:

* Detection of root switch failure is done in 3 hello times, which is 6 seconds if default hello times have not been changed.
* Ports may be configured as edge ports if they are attached to a LAN that has no other bridges attached. These edge ports transition directly to the forwarding state. RSTP still continues to monitor the port for BPDUs in case a bridge is connected. RSTP can also be configured to automatically detect edge ports. As soon as the bridge detects a BPDU coming to an edge port, the port becomes a non-edge port.
* Unlike in STP, RSTP will respond to BPDUs sent from the direction of the root bridge. An RSTP bridge will “propose” its spanning tree information to its designated ports. If another RSTP bridge receives this information and determines this is the superior root information, it sets all its other ports to discarding. The bridge may send an “agreement” to the first bridge confirming its superior spanning tree information. The first bridge, upon receiving this agreement, knows it can rapidly transition that port to the forwarding state bypassing the traditional listening/learning state transition. This essentially creates a cascading effect away from the root bridge where each designated bridge proposes to its neighbors to determine if it can make a rapid transition. This is one of the major elements that allows RSTP to achieve faster convergence times than STP.
* As discussed in the port role details above, RSTP maintains backup details regarding the discarding status of ports. This avoids timeouts if the current forwarding ports were to fail or BPDUs were not received on the root port in a certain interval.
* RSTP will revert to legacy STP on an interface if a legacy version if an STP BPDU is detected on that port.