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

Understanding SRLB (Segment Routing Local Block)

🔹What is SRLB?

SRLB (Segment Routing Local Block)is arange of local MPLS labelsused bySegment Routing (SR-MPLS).

These labels areonly relevant to the local routerand arenot advertised to other routers.

🔹Key SR-MPLS Label Blocks:

✅SRGB (Segment Routing Global Block)– Globally significant labels shared among routers.

✅SRLB (Segment Routing Local Block)– Locally significant labels, not shared.

Why is the Answer TRUE?

✅SRLB labels are only locally defined and are NOT distributed via IGP (OSPF or IS-IS).

✅They are used for local forwarding decisions within an SR-enabled router.

✅Only SRGB labels are advertised to ensure consistent global label assignment.

Real-World Application:

Traffic Engineering (TE):Uses SRLB forcustom local path optimizations.

Segment Routing Networks:Ensuresscalable MPLS forwardingwithout requiring full LDP signaling.

✅Reference:Huawei HCIE-Datacom Guide – Segment Routing Label Blocks (SRGB & SRLB)

Understanding IRB (Integrated Routing and Bridging) Forwarding in VXLAN

VXLAN (Virtual Extensible LAN) supportsLayer 2 and Layer 3 forwardingbetween Virtual Network Identifiers (VNIs).

IRB (Integrated Routing and Bridging)enables inter-subnet communication within a VXLAN fabric.

There aretwo modes of IRB forwarding:

Symmetric IRB

Asymmetric IRB

Why the Answer is "Symmetric" IRB Forwarding?

✔Ingress VTEP performs both Layer 2 and Layer 3 lookups:

Symmetric IRBrequiresboth ingress and egress VTEPsto performLayer 3 lookups.

Theingress VTEP (source gateway) performs a Layer 2 MAC lookup, then aLayer 3 lookupto find the destination VTEP.

Theegress VTEP (destination gateway) performs another Layer 3 lookupbefore forwarding the packet to the destination.

✔Asymmetric IRB does not perform two lookups at the ingress VTEP:

In Asymmetric IRB,the ingress VTEPperforms both Layer 2 and Layer 3 forwardingandsends a Layer 2 packet to the egress VTEP.

Theegress VTEP only does a Layer 2 lookup, not a Layer 3 lookup.

Since thequestion states that both L2 and L3 lookups occur at the ingress VTEP,asymmetric IRB is incorrect.

✔Why Symmetric IRB is More Common?

Scalability:Supportsany-to-any communicationacross VXLAN networks.

More Efficient Routing:UsesLayer 3 VXLAN encapsulation, ensuring efficient routing between VNIs.

📖Reference:Huawei HCIE Datacom – VXLAN Symmetric and Asymmetric IRB Forwarding

Huawei’suser access authentication configurationincludes the following components:

AAA scheme: Defines how users are authenticated (local, RADIUS, HWTACACS, etc.).

Domain: Groups users and associates them with an AAA scheme.

Access profile: Defines access control rules like 802.1X, MAC, Portal, or multi-mode authentication.

Correct workflow:

Bind theauthentication profile(which references the access profile) to theuser access interface.

Not the other way around.

Incorrect statement:

D.It incorrectly states youbind the access profile to the authentication profile, when in fact, theauthentication profile binds the access profileand is applied to the interface.

Correct answer: D

Understanding User Isolation in the Same VLAN

In a traditional VLAN,all devices within the same VLAN can communicateunless additional security policies are applied.To isolate users within the same VLAN, the following technologies can be used:

✅B. Port Isolation (Private VLAN or Layer 2 Isolation)

Prevents communication between ports within the same VLAN.

Common in enterprise and campus networksto improve security.

Example:Isolating guest users from employees within the same VLAN.

✅C. IPSG (IP Source Guard)

BlocksIP address spoofingwithin the same VLAN.

UsesDHCP snooping binding tableto verify whether a device is using anauthorized IP address.

✅D. Ethernet Port Security

Limits the number of MAC addressesallowed per port.

Preventsunauthorized devicesfrom communicating within the VLAN.

❌A. Super VLAN (Incorrect Choice)

Super VLANgroups multiple VLANs under a single Layer 3 gateway, but it doesnot provide isolationwithin the same VLAN.

Real-World Application:

Public Wi-Fi Networks:Ensures thatusers within the same VLAN cannot communicatewith each other.

Enterprise Security:Prevents unauthorized access or attacks withinshared VLANs.

✅Reference:Huawei HCIE-Datacom Guide – VLAN Security and User Isolation Technologies

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

Comprehensive and Detailed Explanation:

✔The Best Protection Against MITM and Spoofing Attacks:

✅(D) Associating DHCP Snooping with IPSG (IP Source Guard) and DAI (Dynamic ARP Inspection)providescomplete protectionby:

Blocking rogue DHCP servers.

Preventing MAC/IP spoofing.

Ensuring only valid clients access the network.

✔Why Not Other Options?

❌(A) Configuring trusted/untrusted interfacesonly helpsblock rogue DHCP servers, but does not prevent spoofing.

❌(B) Limiting MAC address learningprevents MAC flooding, but does not stopMITM attacks.

❌(C) Checking the CHADDR field in DHCP Snoopinghelps detectspoofed requests, but does not block all MITM scenarios.

📖Reference:Huawei HCIE Datacom – Security Mechanisms for Intranet Protection

A screenshot of a computer AI-generated content may be incorrect.

IPsec (Internet Protocol Security) provides secure communication over IP networks through several essential functions. Let’s explain each function and its purpose:

1. Data Origin Authentication:

Description:The receiver verifies the identity of the sender.

This function ensures that the data received actually comes from the claimed source.

IPsec achieves this usingIKE (Internet Key Exchange)anddigital signatures.

TheAuthentication Header (AH)andEncapsulating Security Payload (ESP)support authentication.

Use Case:Verifying that a message claiming to be from a specific IP address is genuinely from that source.

2. Data Encryption:

Description:The sender encrypts the data, and the receiver decrypts the data.

Encryption ensuresdata confidentialityby transforming readable data (plaintext) into unreadable data (ciphertext).

Only the intended receiver with the correct decryption key can convert the ciphertext back to plaintext.

Common encryption algorithms used includeAES (Advanced Encryption Standard)andDES (Data Encryption Standard).

Use Case:Protecting sensitive data transferred over public networks.

3. Data Integrity:

Description:The receiver verifies received data to determine whether the data has been tampered with.

Ensures that the data was not altered during transmission.

Uses cryptographichash functions(e.g.,SHA-1, SHA-256) to generate amessage digest.

The digest is sent with the data and verified on the receiving side.

Use Case:Detecting any changes made to the data packet during transmission.

4. Anti-Replay:

Description:The receiver rejects duplicate data packets.

Prevents attackers from capturing packets and replaying them later.

Usessequence numbersto detect replayed or duplicated packets.

The receiver keeps asliding windowof sequence numbers to compare incoming packets.

Use Case:Blocking malicious actors from sending previously intercepted packets to disrupt communication.

Why This Mapping Is Correct:

The functions and descriptions are aligned based on the core concepts of IPsec and the roles they play in ensuring secure data transmission.

Each function addresses a specific aspect of security:authentication, confidentiality, integrity, and replay protection.

Understanding Telemetry Encoding Formats

🔹What is Telemetry?

Telemetry is a real-time network monitoring methodthat provideshigh-frequency data collection.

Used inAI-driven networks for predictive analytics and automation.

🔹Common Telemetry Encoding Formats:

✅GPB (Google Protocol Buffers)

Highly efficient binary formatthat reducesmessage size and CPU overhead.

Commonly used forhigh-speed, real-time analytics.

✅JSON (JavaScript Object Notation)

Human-readable format, widely used inRESTful APIs.

Less efficientthan GPB in high-speed telemetry buteasier to debug.

🔹Why is the Answer FALSE?

❌GPB is not mandatory; JSON can also be used in telemetry.

✅Huawei supports both GPB and JSON telemetry encoding formats.

Real-World Application:

Cloud Networking:UsesGPB for fast data collectionandJSON for API-based telemetry visualization.

AI-Driven Networks:High-speedAI analyticsleverageGPB encodingfor efficiency.

✅Reference:Huawei HCIE-Datacom Guide – Telemetry Encoding Formats and Data Collection