Huawei H12-821_V1.0 問題集

質問 1：
During the DHCP interaction process, the DHCP server and client exchange various types of packets. Which of the following packets is not sent from the client to the server?
A. DHCP Discover
B. DHCPNAK
C. DHCP Request
D. DHCP Release
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 2：
On a P2P IS-IS network, after a neighbor relationship is established between R1 and R2, R2 finds that its LSDB is not synchronized. Then, R2 requests corresponding LSPs from R1 for LSDB synchronization. The following figure shows the synchronization process. Drag the following packet types to the steps in which they are used.(Token is reusable)
正解：
Explanation of IS-IS Packet Types and Synchronization Process:
In the given scenario, R2 requests LSPs from R1 to synchronize its Link State Database (LSDB). The following IS-IS packet types are involved in this synchronization process:
1. P2P IIH (Point-to-Point IS-IS Hello):
* Purpose: Establishes and maintains IS-IS neighbor relationships.
* Step: This packet is exchanged initially to detect and maintain the adjacency between R1 and R2.
2. PSNP (Partial Sequence Number PDU):
* Purpose: Requests missing or outdated LSPs (Link State PDUs) from a neighbor to synchronize the LSDB.
* Step: In this case, R2 sends a PSNP to R1 to request the missing or outdated LSP.
3. LSP (Link State PDU):
* Purpose: Contains routing information and is used to update the LSDB.
* Step: R1 sends the requested LSPs to R2 for synchronization.
4. CSNP (Complete Sequence Number PDU):
* Purpose: Lists all LSPs in the sender ' s LSDB to help neighbors verify and request missing LSPs.
* Step: R1 sends a CSNP during retransmission timeout to notify R2 of its LSPs.

質問 3：
On an STP network, the root bridge, root port, and designated port are elected in sequence. The election rules of these ports are different. List the steps for electing the root port in sequence.
正解：
Explanation of Root Port Election in STP:
In a Spanning Tree Protocol (STP) network, the Root Port is selected on each switch (except the Root Bridge). The Root Port is the port with the lowest path cost to the Root Bridge. If there is a tie in path cost, the following criteria are used in sequence to break the tie:
Steps for Root Port Election in Sequence:
* RPC Comparison (Root Path Cost):
* The port with the lowest Root Path Cost is preferred.
* Root Path Cost is the cumulative cost of the path to the Root Bridge.
* Peer BID (Bridge ID) Comparison:
* If the Root Path Costs are equal, the Bridge ID of the connected switch (peer) is compared.
* The port connecting to the switch with the lower Bridge ID is preferred.
* Peer PID (Port ID) Comparison:
* If the Bridge IDs are equal, the Port ID of the peer ' s sending port is compared.
* The port connecting to the lower Port ID is preferred.
* Local PID (Port ID) Comparison:
* If all else is equal, the Local Port ID of the switch is used.
* The port with the lower Local Port ID is selected.

質問 4：
The figure shows the VRRP status switchover events . Match these events with their sequence numbers.


正解：

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.

質問 5：
Based on IGMP snooping, IGMP snooping proxy enables a switch to act as a substitute for an upstream Layer
3 device to send IGMP Query messages to downstream hosts, and also to act as a substitute for downstream hosts to send IGMP Report/Leave messages to an upstream device. As such, this function conserves bandwidth between the upstream device and the local device.
A. FALSE
B. TRUE
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 6：
STAs stay on different subnets before and after Layer 3 roaming. To enable the STAs to access the original network after roaming, network engineers need to configure user traffic to be forwarded to the original subnet over a CAPWAP tunnel.
A. FALSE
B. TRUE
正解：B
解説: (Topexam メンバーにのみ表示されます)