H12-821_V1.0 Exam Dumps : HCIP-Datacom-Core Technology V1.0

A is false– Ports in MSTP can havedifferent roles and statesin different MSTIs. Each MSTI can independently elect a root and compute its own topology, which results indifferent port states per MSTI.

B is true– MSTIs use thesame spanning tree algorithm as STP (and RSTP)for calculating the spanning tree topology.

C is true– Each MSTI may have adifferent root bridgeand separate topology, depending on VLAN mappings.

D is true– MSTIs do not independently send BPDUs;only MSTI 0 (CIST)actually sends BPDUs, and information about other MSTIs is encapsulated within it. So thestatement is worded to test conceptual understanding, but not incorrect in MSTP context as framed.

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“MSTP allows different MSTIs to have different topologies. A port may be forwarding in MSTI 1 but blocking in MSTI 2. This independence improves VLAN-based traffic engineering.”

(Chapter: MSTP Concepts – Section: MSTI Behavior and Port Roles)

Comprehensive and Detailed Step-by-Step Explanation:

BGP Route Filtering:

BGP provides flexible policies for route filtering to optimize routing table size and reduce network resource usage.

By configuringroute filters, a device can advertise only required routes to peers, thereby improving efficiency.

Purpose of Filtering:

Reduces the routing table size.

Decreases CPU and memory usage on routers.

Limits unnecessary route propagation.

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.