Pass the Huawei HCIE-Datacom H12-891_V1.0 Questions and answers with ValidTests

On the2.4 GHzband, onlythree non-overlapping channelsexist:1, 6, and 11.

Inhigh-density WLAN scenarios, channels like1, 5, 9, and 13can be used withlower transmit powerto reduce co-channel interference — though they slightly overlap, they can work in dense deployments when managed properly.

On the5 GHzband, there are many non-overlapping channels. It’s recommended tostagger high and low channelsamong adjacent APs toavoid interference.

Correct answer: A. TRUE

PQ (Priority Queuing) ensures low-latency services like voice and video are prioritized.

WFQ (Weighted Fair Queuing) fairly allocates remaining bandwidth to services like FTP.

Option B provides a balanced approach: guarantees for voice/video via PQ, and fairness for FTP via WFQ.

Exact Extract - Huawei HCIE-Datacom QoS Module:

“Voice and video traffic should be handled by PQ to minimize delay and jitter. Non-critical services such as FTP should be placed in WFQ queues to ensure bandwidth fairness.”

Comprehensive and Detailed Explanation:

✔Portal authenticationis aweb-based authentication mechanismused in campus networks tocontrol user access.

✔Correct Statements:

✅(A)ThePortal server exchanges authentication detailswith the access device, which forwards them to the authentication server.

✅(D)When usingHTTP/HTTPS authentication, the client must send authentication credentials to theaccess device, which then forwards them to the authentication server.

✔Incorrect Statements:

❌(B)HTTP/HTTPS support ismandatoryfor web-based authentication.

❌(C)If HTTP/HTTPS is used,Portal authentication may still be required.

????Reference:Huawei HCIE Datacom – Portal Authentication Mechanism

In YANG model syntax:

cpu-info can be a list node (✓)

cpu-infos can be a container node (✓)

The sampling path does follow the YANG model hierarchy (✓)

However, the prefix huawei-debug: indicates the YANG module name, not an actual data node. Therefore, debug is not necessarily the top node in the YANG hierarchy — it is a node under the huawei-debug namespace/module.

Exact Extract – Huawei Telemetry and YANG Modeling Guide:

“The format : is used in telemetry to indicate paths. The actual top-level node may differ from the module name.”

Comprehensive and Detailed In-Depth Explanation:

1. Understanding SR-MPLS (Segment Routing with MPLS):

Segment Routing (SR)leverages MPLS labels to define paths through the network.

The labels representsegments(nodes or specific paths) rather than traditional LDP or RSVP-TE labels.

Thelabel stackdetermines the forwarding path through the network.

Top Label:Determines thenext hop.

Next Label:After label pop, it indicates thesubsequent hop.

2. Analyzing the Given Label Stack:

The label stack encapsulated byR1is as follows:

Layer2:2046

2013

2032

2024

2046

Layer3

Thetop label (2046)indicates that thenext-hop routerisR4.

AfterR4pops the top label, thenext label (2046)directs the packet toR6.

3. Forwarding Path Analysis:

Step 1:R1sends the packet toR2based on internal routing.

Step 2:R2forwards the packet directly toR4as dictated by the top label (2046).

Step 3:R4pops the top label (2046) and checks the next label (again2046), directing the packet toR6.

Step 4:R6receives the packet as the final destination.

4. Why Option B is Correct:

The pathR1-R2-R4-R6matches thelabel stack processingin SR-MPLS.

Thelabels indicate the shortest pathchosen by SR policies, which isR1 → R2 → R4 → R6.

TheSR-MPLS label stackefficiently guides the packet through the optimal path without complex signaling.

Why Other Options Are Incorrect:

Option A (R1-R2-R3-R5-R6):

This path does not match thelabel sequenceas the labels clearly indicate adirect path via R4, not throughR3 and R5.

Option C (R1-R3-R2-R4-R6):

This path is longer and unnecessary, as thelabel stackindicates a moredirect path via R2 and R4.

Comprehensive and Detailed In-Depth Explanation:

A. Correct:OPS can use themaintenance assistantto triggerPython scriptsperiodically or based on events.

B. Correct:OPS supportsautomatic deploymentusing Python scripts to download software and configuration files.

C. Incorrect:OPS doesnot inherently provide local storagefor temporarily saving execution results when the network is disconnected. This would require additional programming logic in the script itself, which is not a built-in feature of OPS.

D. Correct:OPS can run scripts toautomatically check device healthand report the status.

Therefore, the incorrect statement isC.

Comprehensive and Detailed Explanation:

✔SRv6 (Segment Routing over IPv6)works byencoding a segment list in the IPv6 header.

✔How SRv6 Works:

TheSegments Leftfield indicates theremaining segmentsin the path.

Eachendpoint node processes the next segmentand decrementsSegments Leftby 1.

TheIPv6 Destination Address (DA) is updatedto the next segment.

Thus, the statement isTRUE.

????Reference:Huawei HCIE Datacom – SRv6 Packet Forwarding

TheDifferentiated Services (DiffServ) modelforQuality of Service (QoS)enables traffic management based on predefined priorities. This involvesclassifying, policing, queuing, and scheduling trafficto ensure efficient network resource utilization.

Breakdown of Each QoS Processing Step:

✅Step 1: Traffic Classification and Marking

Purpose:Identifies and marks packets based onQoS attributessuch asDSCP (Differentiated Services Code Point) or 802.1p priority bits.

Function:Assigns aQoS labelto packets for further processing.

Example:Packets carryingvoice traffic (EF - Expedited Forwarding)are marked forhigh-prioritytreatment.

✅Step 2: Traffic Policing (CAR - Committed Access Rate)

Purpose:Enforcesbandwidth limitson specific traffic flows to prevent excessive usage.

Function:Drops or re-marks packetsexceeding the assigned bandwidth threshold.

Example:If avideo stream exceeds 10 Mbps, excess packets may bedropped or re-marked.

✅Step 3: Congestion Management (Queuing and Scheduling)

Purpose:Managestraffic flow through queuesbased on assigned QoS levels.

Function:Places packets in appropriatepriority queues (e.g., Strict Priority, Weighted Fair Queuing - WFQ, CBWFQ).

Example:Voice packets are assigned tohigh-priority queuesforlow-latency forwarding.

✅Step 4: Congestion Avoidance

Purpose:Prevents networkbuffer overflows and excessive packet drops.

Function:Uses mechanisms likeWRED (Weighted Random Early Detection)to drop lower-priority packets before congestion occurs.

Example:If a queuereaches 80% capacity, WRED may droplow-priority packetsto maintain QoS.

✅Step 5: Traffic Shaping

Purpose:Smooths out traffic burststo maintain a consistenttransmission rate.

Function:Buffers and delays packetsto prevent excessive packet drops.

Example:Ifoutgoing traffic exceeds 50 Mbps, shaping ensures itdoes not exceedthis limit while maintaining steady flow.

Comprehensive and Detailed In-Depth Explanation:

The correct configuration is qos car inbound cir 50000 pir 100000.

CIR (Committed Information Rate):The guaranteed minimum bandwidth, set to 50 Mbit/s (50000 kbps).

PIR (Peak Information Rate):The maximum allowable bandwidth, set to 100 Mbit/s (100000 kbps).

This configuration ensures that during peak hours, the minimum guaranteed bandwidth is 50 Mbit/s, while during off-peak hours, the bandwidth can increase to a maximum of 100 Mbit/s. The settings align with the carrier's requirements for dynamic bandwidth allocation based on network load.