Huawei Updated H12-821_V1.0 Exam Questions and Answers by elis

The default sending interval for BFD (Bidirectional Forwarding Detection) control packets is 100 milliseconds. This interval ensures rapid detection of link faults, providing fast failover and minimizing downtime in network operations ​.

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)

From the command output, the interface S4/0/0 has its cost value explicitly listed under theCostsection as 20 for Level-1 circuits. This means that all traffic routed through this interface will incur this cost in the IS-IS metric calculation. The other options (such as circuit level and IPv6 support) are either not correct or not supported by the provided output ​.