Huawei H12-891_V1.0 - HCIE-Datacom V1.0

Comprehensive and Detailed Explanation:

VGMP (Virtual Group Management Protocol)is used inHuawei firewallsforhot standby and high availability.

When is VGMP Activated?✔Whenhot standby is enabled, firewalls must synchronize their states to maintain failover capability.✅✔VGMPsends packets periodicallyto check if the standby firewall is operational.

Why Other Options Are Incorrect?❌Priority increase (B):Does not trigger VGMP packets directly.❌Link detection timeout (C):Affects failover but does not initiate VGMP packets.❌Hot standby being disabled (A):Disables VGMP, preventing packets from being sent.

Thus, the correct answer isD.

📖Reference:Huawei HCIE Datacom – Firewall Hot Standby and VGMP

In MPLS (Multiprotocol Label Switching), Label Switching Routers (LSRs) handle packets based onFECs (Forwarding Equivalence Classes)and their positions in the label-switched path:

Ingress LSR:The entry point for labeled packets; it classifies packets into FECs and assigns the initial label.

Transit LSR:Intermediate routers that swap labels and forward packets along the LSP.

Egress LSR:The last router in the LSP that removes the label and forwards the packet normally.

An LSRcannotbeboth an ingress and a transit router for the same FEC, because an ingress LSR is defined as thestarting pointfor that specific FEC's LSP. If it’s the ingress, it means the labeled pathstarts there, so it can't be in themiddle (transit)of that same path.

Therefore, the statement isFALSE.

Comprehensive and Detailed In-Depth Explanation:

During a network migration test, it is crucial not only to verify that the network itself is functioning correctly but also to ensure thatupper-layer application servicesare running properly on the newly migrated network. Migration testing aims to confirm that the transition has not disrupted service functionality.

Option A and C focus solely on network performance, which is necessary but insufficient.

Option B refers to command outputs, which are technical checks and do not guarantee service continuity.

Option D correctly identifies that successful migration is indicated byproper operation of upper-layer application services, as the primary purpose of a network is to support these applications.

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

The command output shows:

*>i before both networks, which means these routes are the preferred routes (*) and are learned via internal BGP (i).

Two networks are listed: 3002::3 and 3002::4, which means R1does havethese two routes in its BGP IPv6 routing table.

For 3002::4, the path origin shows 65001 i, which means this route originated from AS 65001 and was learned through IBGP.

The AS Path attribute is only shown for 3002::4, but both routes are clearly present.

Therefore, the correct conclusion is:

D. R1 has routes 3002::3/128 and 3002::4/128.

InHTTP status codes:

401 Unauthorized: The server has received the request butrequires authentication. This typically means:

No token or credentials were provided.

Credentials/token were incorrect or expired.

Other options:

403 (Access Denied)would mean correct credentials butinsufficient permissions.

404: Resource does not exist.

503: Service unavailable.

Correct answer: A. Unauthorized

Huawei IPsec supports multiple modes for establishing Security Associations (SAs):

A. Template negotiation — Used in IPsec policy templates and dynamic VPNs.

B. IKE auto-negotiation mode — Automatically negotiates parameters via IKE Phase 1/2.

C. Certificate negotiation — IPsec peers can authenticate each other using certificates during IKE negotiation.

D. Manual mode — Static IPsec SAs can be manually configured without IKE, often used in simple or static topologies.

Exact Extract - Huawei Security Configuration Guide (USG Series):

“IPsec SAs can be established manually or dynamically through IKE, including using PSKs or certificates. Template-based approaches simplify large-scale deployment.”

Link-LSA (Type 8)in OSPFv3 performs the following:

Advertises therouter’s link-local addressto neighbors.

Advertises therouter’s interface IDon the link.

CarriesIPv6 prefixesassociated with the interface (since Router LSA no longer does this in OSPFv3).

TheOptions field in Link-LSAcontainscapabilities of the originating router,notthe options from Network-LSA.

So,Option D is incorrect— the Link-LSA doesnot advertise options from the Network-LSA.

Correct answer: D

Understanding 6PE & 6VPE in MPLS Networks

6PE (IPv6 Provider Edge) and 6VPE (IPv6 VPN Provider Edge) areMPLS-based solutionsthat allowIPv6 trafficto be carried over anMPLS IPv4 core networkwithout requiring the entire backbone to support IPv6.

🔹6PE (IPv6 over MPLS - No VPN)

Used forglobal IPv6 routingwithout VPN segmentation.

No need forVRFs (VPN Routing and Forwarding instances)because IPv6 prefixes arehandled natively.

🔹6VPE (IPv6 VPN over MPLS - Supports VPNs)

ExtendsMPLS L3VPNto supportIPv6 routing inside VPN instances.

UsesMP-BGP VPNv6to distribute IPv6 prefixes insideMPLS VPNs.

Why is the Answer TRUE?

✅No VRFs are required for 6PE:

6PEonly needs BGP labeled IPv6 routesin theglobal routing table.

IPv6 prefixes are carried usingMPLS labelswithout VPN segmentation.

✅VRFs are required for 6VPE, NOT for 6PE:

6VPE requires VPN instances (VRFs)forIPv6 L3VPNs, but6PE does not.

✅Real-World Application:

6PE is used in large ISP networkswhere IPv6 deployment is needed butwithout VPN separation.

6VPE is used for enterprise MPLS VPNs, allowing customers to haveisolated IPv6 routing tables.

✅Reference:Huawei HCIE-Datacom Guide – MPLS IPv6 Transition Technologies (6PE & 6VPE)

Virtual Networks in Huawei CloudCampus Solution:

Virtual networks (VNs) aresegmented based on services(e.g., IoT, Guest Wi-Fi, Enterprise Wi-Fi).

Each VN has its ownrouting and forwarding instance(VRF).

Isolation Between Virtual Networks:

By default,different virtual networks are isolated.

If inter-VN communication is required, it must be manually configuredusingpolicy-based routing (PBR), inter-VRF routing, or firewall policies.

Reference from Huawei HCIE-Datacom Documentation:

Huawei CloudCampus Solution Guide – Virtual Networks and Segmentation

HCIE-Datacom Training Material – Policy-Based Inter-VN Communication