H12-891_V1.0 Exam Dumps - HCIE-Datacom V1.0

From the IS-IS error output, the key error is:

Mismatched Area Addr(L1): 13

This clearly indicates that the area addresses are different, which prevents the Level-1 adjacency from forming.

Why is Option D Correct?

IS-IS Level-1 routers must have the same area ID to form an adjacency.

Since the log shows a mismatched area address, the adjacency fails at Level-1.

If R3 and R4 were Level-2 routers, they could form an adjacency even with different area IDs.

Why Are the Other Options Incorrect?

❌ Option A: No authentication failure is reported.

❌ Option B: No " Mismatched Level " errors appear, so their levels are compatible.

❌ Option C: No " Bad Circuit Type " errors indicate mismatched circuit types.

Thus, the correct answer is D.

📖 Reference: Huawei HCIE Datacom – IS-IS Neighbor Troubleshooting

BGP in Huawei SD-WAN

Huawei SD-WAN uses BGP (Border Gateway Protocol) as the primary routing protocol to exchange VPN routes between Customer Premises Equipment (CPEs) and the controller.

✅ Why BGP is Used in SD-WAN?

Scalability: BGP can handle a large number of VPN routes.

Policy-Based Routing: BGP allows traffic engineering and policy control across SD-WAN tunnels.

Multiprotocol Support: Huawei SD-WAN uses MP-BGP to exchange IPv4, IPv6, and VPNv4 routes.

Let ' s dissect each option based on OSPFv3 LSA behavior from Huawei HCIE Datacom documentation.

✅ Option A: Correct

OSPFv3 uses Router LSAs (Type 1) to describe the local interfaces, links, and neighbors.

R1, as part of Area 0, will generate Router-LSAs and receive Router-LSAs from neighbors in the same area (R2 and R3 via switch S1).

Huawei Datacom Reference:

" Each OSPFv3 router originates a Type 1 Router LSA for each area it belongs to. "

(Source: HCIE-Datacom Study Guide v3.0 - OSPFv3 Fundamentals)

❌ Option B: Incorrect (Correct Answer)

Link-LSAs (Type 8) are not sent between routers. They are only generated for each link on which the router has at least one neighbor. These LSAs are only flooded on the local link.

R1 cannot receive two Link-LSAs from R2 about both links. It can only receive the Link-LSA that R2 generates for the shared link with R1. The other link (e.g., to R4 in Area 1) is irrelevant to R1.

Huawei Datacom Reference:

" A Link LSA is generated by a router for each attached link and is sent only to the routers on the same link. "

(Source: HCIE-Datacom Study Guide v3.0 - OSPFv3 LSA Types)

✅ Option C: Correct

On broadcast links, DRs generate Type 2 Network LSAs.

If R3 is the DR on the shared segment (with R1), R1 will have the Network-LSA from R3 in its LSDB.

Huawei Datacom Reference:

" The DR on a broadcast network generates a Type 2 Network LSA to describe all routers on that link. "

(Source: HCIE-Datacom Study Guide v3.0 - OSPFv3 LSDB Construction)

✅ Option D: Correct

R2 connects Area 0 and Area 1, hence it ' s an ABR.

ABRs generate Type 3 Inter-Area-Prefix LSAs to advertise IPv6 prefixes from one area to another.

R2 advertises Area 1 prefixes to Area 0 routers (R1 and R3).

Huawei Datacom Reference:

" Inter-Area-Prefix LSAs (Type 3) are generated by ABRs to advertise IPv6 prefixes from one area into another. "

(Source: HCIE-Datacom Study Guide v3.0 - ABR Functionality in OSPFv3)

In MPLS Traffic Engineering (TE), Label Switched Paths (LSPs) can be established:

Statically: Manual configuration.

Dynamically: Typically via RSVP-TE.

Protocol roles:

RSVP-TE: Used to dynamically establish and signal TE LSPs → ✅

OSPF / IS-IS: Act as IGP protocols and provide TE-related link-state information (like bandwidth) but do not establish LSPs themselves → ❌

BGP: Used for route advertisement, not for LSP setup in MPLS TE → ❌

Correct answers: A, C, D

Understanding L3VPNv4 Over SRv6 BE

🔹 What is L3VPNv4?

L3VPNv4 (Layer 3 VPN over IPv4) allows MPLS-based VPN services over an SRv6 backbone.

Uses MP-BGP (Multiprotocol BGP) to distribute VPN routes.

🔹 Why is an RR (Route Reflector) Needed?

An RR simplifies BGP route exchange between multiple PEs (Provider Edge routers).

Without proper configuration, RRs may filter VPNv4 routes, preventing PEs from learning routes correctly.

Why is the Command peer retain-route-target all Needed?

✅ Ensures that the RR retains all VPNv4 routes.

✅ Prevents the RR from filtering route targets (RTs), allowing full VPN reachability.

✅ Without this command, the RR might not reflect all VPNv4 routes, causing connectivity issues.

Real-World Application:

Enterprise MPLS VPNs: Ensures correct BGP route reflection in an SRv6-based L3VPN.

Carrier Networks: Helps service providers maintain full BGP VPN route distribution.

✅ Reference: Huawei HCIE-Datacom Guide – BGP Route Reflectors in L3VPN over SRv6

IS-IS (Intermediate System to Intermediate System) protocol has a limit on the size of Link-State PDUs (LSPs).

Why Fragmentation?

LSPs contain routing and topology information.

If the LSP exceeds the maximum size, fragmentation allows the device to store and forward more routes by breaking them into smaller LSPs.

Key Point: IS-IS fragmentation is essential in large-scale networks where routing tables grow beyond the default LSP size limit.

✅ Reference: Huawei HCIE-Datacom Guide - IS-IS Protocol and Route Scaling

In BGP, community attributes help control the advertisement scope of BGP routes. Here’s what each option means:

No_Export: This well-known community attribute prevents BGP routes from being advertised to external BGP (EBGP) peers. Routes with this attribute can still be advertised to internal BGP (IBGP) peers within the same AS. This ensures that the route remains within the originating AS.

No_Advertise: This attribute means that the route should not be advertised to any BGP peer, whether internal or external.

Internet: Indicates that the route can be advertised to all BGP peers, both internal and external, with no restrictions.

No_Export_Subconfed: Similar to No_Export, but it also restricts advertisement to peers within a BGP confederation. It ' s more specific and not generally used just to keep routes inside one AS.

Therefore, the correct answer is B. No_Export, as it is the attribute that ensures BGP routes remain within the AS by not being sent to EBGP peers.

Huawei AR routers used as egress gateways in CloudCampus solutions support multiple onboarding and deployment methods, including:

DHCP Option 148-based auto-deployment

Web-based management

CLI-based deployment and configuration (also supported)

So, the statement is incorrect—CLI-based deployment is supported.

Exact Extract - Huawei CloudCampus AR Router Deployment Guide:

“AR series routers support multiple deployment methods including CLI, DHCP Option 148, and web-based registration.”