Huawei Updated H12-891_V1.0 Exam Questions and Answers by indy

Comprehensive and Detailed Explanation:

The IS-IS peer output shows:

IPv4 Peer Address:10.1.34.1

IPv6 Peer Address:FE80::2E0:FCFF:FE98:2576

MT IDs (Multi-Topology) Supported:0 (IPv4), 2 (IPv6)

Sinceboth IPv4 and IPv6 peer addressesare listed, it confirms thatboth IPv4 and IPv6 IS-IS neighbor relationships are establishedbetweenR4 and ee8c.a0c2.baf3.

????Reference:Huawei HCIE Datacom – IS-IS Multi-Topology Support

Network Slicing Using Channelized Sub-Interfaces and FlexE

Bothchannelized sub-interfacesandFlexE (Flexible Ethernet)are used fornetwork slicing, but they have differentapplication scenarios:

✅A. Channelized sub-interface is recommended for interfaces with bandwidth < 50 Gbit/s.

Channelized sub-interfacessplit a physical interfaceinto multiple logical sub-interfaces.

Best for lower-bandwidth links (<50 Gbit/s).

✅B. FlexE is recommended for 50GE and higher-rate interfaces.

FlexEdivides a high-bandwidth physical link(e.g.,100GE, 400GE) into multiple virtual slices.

Used in high-speed backbone and data center networks.

✅C. Only FlexE-based network slicing can be deployed across OTN devices.

FlexE is compatible with Optical Transport Network (OTN)and can be used for long-haul slicing across OTN.

❌D. Only channelized sub-interface-based network slicing can be deployed across MSTP devices.

Incorrect!While MSTP supports channelized interfaces,FlexE is not restricted to MSTP deployment.

Reference from Huawei HCIE-Datacom Documentation:

Huawei FlexE Technology Whitepaper – Network Slicing in Transport Networks

HCIE-Datacom Training Material – Channelized Sub-Interface and FlexE in Network Slicing

VRRP (Virtual Router Redundancy Protocol) and Flapping

VRRP ensuresgateway redundancyby allowing multiple routers to work together as avirtual router.Flappingoccurs when themaster and backup routers frequently switch roles.

Causes of VRRP Flapping:

✅A. Too small interval between Advertisement packet transmissions–Can cause flapping

If theAdvertisement interval is too short, frequent VRRP state changes can occur.

✅C. Packet loss on an interface of the backup device–Can cause flapping

If thebackup router loses VRRP packets, it might assume themaster is downand initiate an election.

✅D. Flapping on the link transmitting VRRP Advertisement packets–Can cause flapping

If the link used for VRRPexperiences instability, packets may be lost, triggering VRRP role changes.

Incorrect Answer Explanation:

❌B. Inconsistent preemption delay settings – Does NOT cause VRRP flapping

Preemption delay only affectswhen a router takes over as masterafter recovering from a failure.

It doesnot directly cause flappingbecause the role change happens onlyafter a delay, preventing frequent transitions.

Reference from Huawei HCIE-Datacom Documentation:

Huawei VRRP Configuration Guide – Preventing VRRP Flapping

HCIE-Datacom Study Material – VRRP Timers and Stability

Comprehensive and Detailed Explanation:

✔BIER vs. PIM Multicast Routing:

BIER (Bit Index Explicit Replication)eliminates the need formulticast distribution trees (MDTs)by encodingreceiver information into the packet header.

PIM (Protocol Independent Multicast)requiresMDTs to manage multicast forwarding paths.

✔Correct Statements:

✅(A) BIER uses a Bitstring fieldin packet headers for forwarding.

✅(B) PIM builds MDTsto define multicast paths.

✅(C) BIER does NOT require MDTs, making it more scalable.

❌(D) Incorrect→ BIER does not require hop-by-hop join messages.

????Reference:Huawei HCIE Datacom – BIER and PIM Comparison