In RSTP, a port in the discarding state neither forwards data frames nor learns MAC addresses. A port in the learning state does not forward data frames but starts learning MAC addresses. Therefore, options A and B are correct, while C and D are incorrect due to misunderstandings of these states .

Comprehensive and Detailed In-Depth Explanation:
* STP Port Roles:
* Root Port (RP) # Connects directly to the Root Bridge.
* Designated Port (DP) # Forwards traffic for a given segment.
* RSTP introduces two additional roles to improve redundancy:
* Backup Port # A redundant Designated Port (on the same switch).
* Alternate Port # A backup Root Port (path to the Root Bridge).
* All four roles exist in RSTP, making the correct answer A, B, C, D.
# Reference: Huawei HCIA-Datacom Study Guide, RSTP Port Roles and Rapid Convergence.

Explanation:
1 # A Startup message with a priority of 255 is received.2 # A Startup message with a priority less than 255 is received.3 # A Shutdown message is received.4 # The Master_Down timer expires, an Advertisement packet with the priority of 0 is received, or a packet with a priority lower than the local priority is received.5 # A packet with a priority higher than the local priority is received.6 # A Shutdown message is received.
# Reference: Huawei HCIA-Datacom Study Guide, VRRP Status Transitions.

Comprehensive and Detailed Step-by-Step Explanation:
1. Understanding IGMP (Internet Group Management Protocol):
* IGMP is used in multicast networking to manage membership of devices in multicast groups.
* Key parameters in the configuration provided:
* Interface IP Address: 192.168.1.1
* IGMP Version: 2
* Query Interval (Configured): 60 seconds
* Maximum Query Response Time: 10 seconds
* Querier Address: 192.168.1.1
2. Analysis of Each Statement:
Option A: The IP address of the interface is 192.168.1.1.
* Correct (True Statement).
* The configuration clearly shows that the IP address of the interface is 192.168.1.1.
Option B: The maximum response time to Query messages is 10s.
* Correct (True Statement).
* The configuration explicitly mentions: Value of maximum query response time for IGMP: 10 s.
Option C: The interval for sending Group-Specific Query messages is 60s.
* Incorrect (False Statement).
* The 60-second value refers to the query interval, which is the time interval between general queries sent by the querier.
* The interval for group-specific queries is not specified in this configuration. It is determined dynamically based on the multicast environment and is usually shorter than the general query interval.
Option D: The IGMP version is IGMPv2.
* Correct (True Statement).
* The configuration specifies: Current IGMP version is 2.
3. Why Option C is False:
* The 60-second value is for general query interval, not group-specific query interval.
* The statement misinterprets the configuration, making it false.
4. Summary:
C: (The interval for sending Group-Specific Query messages is 60s).

Comprehensive and Detailed Step-by-Step Explanation:
1. What is the BFD Echo Function?
BFD (Bidirectional Forwarding Detection) is used to detect link failures.
TheEcho functionis an optional feature that tests link connectivity by looping back packets sent from the local device through the forwarding path.
2. Analysis of Each Statement:
Option A: If URPF is enabled on the peer end, BFD packets may be incorrectly discarded on the peer end.
Correct.
URPF (Unicast Reverse Path Forwarding) checks whether the source IP address of an incoming packet is reachable via the interface it was received on. Since the Echo function uses loopback packets, this can conflict with URPF, causing the packets to be dropped.
Option B: In the BFD Echo function, the device uses the IP address of the outbound interface as the source IP address by default.
Correct.
By default, the outbound interface's IP address is used as the source address for BFD Echo packets.
Option C: The BFD Echo function applies only to single-hop BFD sessions.
Incorrect.
The BFD Echo function can be used for both single-hop and multi-hop BFD sessions.
Option D: When configuring a BFD session supporting the BFD Echo function, you need to configure both the local and remote discriminators.
Incorrect.
The BFD Echo function is locally configured and does not require setting remote discriminators. The function operates independently of the remote device's configuration.
3. Summary:
The correct statements areAandB.
Reference:
Huawei HCIA-Datacom Study Guide, Chapter "BFD Echo Function Configuration."