Pass the Huawei HCIP-Datacom H12-831_V1.0 Questions and answers with Dumpstech

To mitigate DHCP-based DoS attacks, Huawei switches provide several protective measures through DHCP Snooping:

✅ A. Configure trusted interfaces – Only ports connected to authorized DHCP servers should be marked as trusted. All other interfaces are untrusted and DHCP replies (from rogue servers) will be discarded.

✅ C. CHADDR field verification – DHCP snooping can check the CHADDR field to ensure that the MAC address in the DHCP packet matches the one learned on the port, helping prevent spoofing attacks.

✅ D. Limit MAC address learning – Limits the number of dynamic MAC addresses a port can learn, preventing flooding of DHCP requests with spoofed MACs.

❌ B is incorrect – While DHCP snooping can generate bindings, it does not generate static MAC address entries based on these bindings. Static MAC addresses must be manually configured or generated via port security, not DHCP snooping.

✅ Official Reference from Huawei:

" To prevent DoS attacks caused by a large number of DHCP requests, DHCP snooping allows rate limiting, CHADDR field verification, and trusted port configuration. "

— [Huawei HCIA-Datacom Certification Guide – DHCP Snooping Chapter]

Comprehensive and Detailed In-Depth Explanation:

Understanding the LSA Table in the Figure

The LSDB (Link-State Database) of R4 displays an Intra-Area-Prefix-LSA for Area 0.0.0.1. The table contains:

Three LSAs originating from R4 (10.0.4.4)

Prefixes referencing both Router-LSAs and Network-LSAs

Different Sequence Numbers and Checksums, indicating multiple link-state changes

OSPFv3 LSA Types Relevant to the Question

Router-LSA (Type 1)

Generated by every router to describe its links within an area.

Network-LSA (Type 2)

Generated only by the Designated Router (DR) for multi-access networks (such as Ethernet).

Advertises all routers connected to the same segment.

Intra-Area-Prefix-LSA (Type 9)

Advertises IPv6 prefixes associated with a Router-LSA (Type 1) or Network-LSA (Type 2).

Analysis of Each Statement

A. The three LSAs belong to area 1. ✅ (True)

The table explicitly shows " Intra-Area-Prefix-LSA (Area 0.0.0.1) " , meaning all LSAs are for Area 1.

The Link State IDs also indicate intra-area advertisements.

✅ Statement A is correct.

B. Area 1 is a stub area. ❌ (False)

There is no indication that Area 1 is a stub area.

Stub areas do not receive Type 5 (External) LSAs, and the LSDB does not show Type 3 (Inter-Area) LSAs either.

Network-LSAs (Type 2) are not typically seen in stub areas unless explicitly configured.

❌ Statement B is incorrect.

C. No OSPFv3 neighbor relationship is established on at least one link of R4. ✅ (True)

One LSA references a Router-LSA, while two reference Network-LSAs.

A Router-LSA alone suggests that R4 has at least one point-to-point or unnumbered link with no OSPFv3 adjacency.

This means R4 has an interface with no neighbor (e.g., a passive interface or down link).

✅ Statement C is correct.

D. R4 is the DR on a link. ✅ (True)

The presence of Network-LSAs (Type 2) indicates that a multi-access link exists.

Since R4 is the origin of the Network-LSA, it must be the DR (Designated Router) for that link.

✅ Statement D is correct.

Final Conclusion:

✅ A. The three LSAs belong to area 1. (True)

❌ B. Area 1 is a stub area. (False)

✅ C. No OSPFv3 neighbor relationship is established on at least one link of R4. (True)

✅ D. R4 is the DR on a link. (True)

Thus, the correct answers are: A, C, D.

???? Topology Summary:

R6 has Loopback0 IP: 2000::6/128 in Area 2 (common area).

R4 is in Area 1, which is a totally stub area — it can’t receive external (Type-5) or NSSA (Type-7) LSAs, only default route (::/0).

R1 and R2 are ABRs that connect areas.

R5 and Area 3 are not relevant here because the destination (R6) is in Area 2.

???? Option A: R4 → R2 → R6

❌ False

R4 is in Area 1, and R2 is not connected to Area 1. R4 cannot reach R2 directly, so this path is invalid.

???? Option B: R4 → R1 → R5 → R3 → R6

❌ False

Although technically possible by topology, this path is not optimal and unlikely to be selected by SPF.

Also, R4 would use default routes via R1 (ABR), not route through Area 3 when shorter paths exist.

???? Option C: R4 → R1 → R3 → R6

✅ True

Valid path:

R4 (in Area 1) uses default route to R1 (ABR).

R1 forwards to R3, which connects to R6.

This is a valid and efficient OSPFv3 path.

???? Option D: R4 → R1 → R2 → R6

✅ True

Also valid:

R4 goes to R1 via default.

R1 forwards to R2 (connected to R6).

SPF may select this path depending on link costs.

Both C and D are feasible.

✅ Final Answer: C, D

Official Huawei Extract:

" In a totally stub or NSSA area, routers use default routes learned from the ABR. Forwarding decisions to external or inter-area routes are made at the ABR level (e.g., R1), and the traffic is then forwarded based on SPF calculation. "

— [Huawei HCIA-Datacom Certification Guide – OSPFv3 Area Types and Route Selection]

Comprehensive and Detailed In-Depth Explanation:

Understanding the BGP and IS-IS Network Topology in the Question:

IS-IS Areas:

Area 49.0001 (Level-1 IS-IS): Contains R1, R2, R4, R5.

Area 49.0002 (Level-2 IS-IS): Contains R3, R6.

R2 acts as an ABR (Area Border Router) and redistributes routes between Level-1 and Level-2 using import-route isis level-2 into level-1.

BGP Route Reflection & Peering:

R2 and R5 are Route Reflectors (RRs).

iBGP peering is established among all routers (R1, R2, R3, R4, R5, R6).

R1 and R4 import 192.168.1.0/24 into BGP, meaning this prefix will be advertised to all iBGP peers.

R3 and R6 import 192.168.2.0/24 into BGP, meaning this prefix will also be advertised to all iBGP peers.

Route Distribution Analysis:

A. The route 192.168.2.0/24 in the routing table of R4 has two next hops. ✅ (Correct)

R3 and R6 import 192.168.2.0/24 into BGP.

R2 and R5 (Route Reflectors) learn this route and reflect it to their clients (R1, R3, R4, R6).

R4 receives two valid paths to 192.168.2.0/24 via R2 and R5 (both iBGP peers).

Since both routes have the same BGP attributes and cost, they are installed as equal-cost paths in R4 ' s routing table.

✅ Statement A is correct: The routing table of R4 has two next hops for 192.168.2.0/24.

B. The routing table of R1 contains two equal-cost default routes. ❌ (Incorrect)

In an IS-IS Level-1-2 setup, default routes are usually provided to Level-1 routers from an ABR (like R2).

However, the question does not mention that R1 is receiving two default routes or that it is in an equal-cost multipath (ECMP) scenario.

R1 may have only one default route, depending on route preference and cost.

❌ Statement B is incorrect: The routing table of R1 does not necessarily contain two equal-cost default routes.

C. The routing table of R4 contains two equal-cost default routes. ❌ (Incorrect)

Similar to R1, R4 is also a Level-1 router in IS-IS.

If R4 were receiving default routes from multiple ABRs (R2 and R5), then it could have equal-cost paths.

However, there is no indication that R4 is receiving two default routes in this scenario.

❌ Statement C is incorrect: The routing table of R4 does not necessarily contain two equal-cost default routes.

D. The routing table of R1 contains the route 192.168.2.0/24. ✅ (Correct)

R3 and R6 import 192.168.2.0/24 into BGP.

R2 and R5 (Route Reflectors) reflect this route to their iBGP peers, including R1.

Since R1 is an iBGP client of R2 and R5, it will receive 192.168.2.0/24 and install it in its routing table.

✅ Statement D is correct: The routing table of R1 contains the route 192.168.2.0/24.

Final Conclusion:

✅ A. The route 192.168.2.0/24 in the routing table of R4 has two next hops.

❌ B. The routing table of R1 does not necessarily contain two equal-cost default routes.

❌ C. The routing table of R4 does not necessarily contain two equal-cost default routes.

✅ D. The routing table of R1 contains the route 192.168.2.0/24.

Thus, the correct answers are: A, D.

Comprehensive and Detailed In-Depth Explanation:

To verify the correct answer, let ' s analyze the LSA types in OSPFv3 and how they work in the given topology.

1. Understanding OSPFv3 LSAs in the Figure

From the command output shown in the image:

LS Type: Intra-Area-Prefix-LSA (Type 9 in OSPFv3).

Originating Router: 10.0.2.2 (R2).

Referenced LS Type: 0x2002, which corresponds to a Network-LSA (Type 2).

Prefix Advertised: 2000:23::/64, which is an IPv6 prefix associated with a network segment.

2. What is an Intra-Area-Prefix LSA (Type 9) in OSPFv3?

In OSPFv3, Type 9 LSAs (Intra-Area-Prefix LSAs) describe IPv6 prefixes associated with either Router-LSAs (Type 1) or Network-LSAs (Type 2).

In multi-access networks (e.g., Ethernet), the DR (Designated Router) generates a Network-LSA (Type 2), which represents the shared network segment.

R2 is likely the DR in this topology, meaning it generates a Network-LSA (Type 2) and an associated Intra-Area-Prefix LSA (Type 9) for the subnet.

3. Analyzing Why the Statement is TRUE

R2 (10.0.2.2) is the originator of the Intra-Area-Prefix LSA (Type 9).

The LSA references a Network-LSA (Type 2), confirming that R2 is the DR for the subnet.

This means the LSA is correctly describing the IPv6 prefix associated with the network.

Since the LSA is visible in R3 ' s LSDB, R3 is learning this information from R2.

All these points confirm that the statement is TRUE.

OSPFv3 uses Router-LSAs to describe the routing topology of individual routers within an OSPF area.

Each OSPFv3 router originates a Router-LSA for every area to which its OSPFv3 interfaces belong. Router-LSAs contain information about link types, interface identifiers, neighboring routers, and link costs.

In the displayed topology, R1, R2, and R3 all participate in OSPFv3 Area 0. Because Router-LSAs have area flooding scope, each participating router receives the Router-LSAs generated by the other routers in that area.

Consequently, R2 ' s Area 0 link-state database contains Router-LSAs originated by R1, R2, and R3.

The three routers form one common OSPFv3 area, and no additional area or router is shown.

Therefore, the total number of Router-LSAs in the relevant LSDB is 3.

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 Training Material.pdf

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Comprehensive and Detailed In-Depth Explanation:

The Link Layer Discovery Protocol (LLDP) is used for discovering neighboring devices. The given LLDP output contains key details about the neighboring device (R2), including its system name, interface, and management IP address. Let ' s analyze each option carefully:

Option A: " The sysname of the peer device is R2. " ✅ Correct

The output clearly shows System name: R2, which confirms that the neighbor ' s system name is indeed R2.

Option B: " The interface number of the peer device is GE0/0/0. " ✅ Correct

The Port ID in the LLDP output is GE0/0/0, which matches the statement in Option B.

Option C: " The VLAN ID of the peer device is 1. " ❌ Incorrect

The given LLDP output does not mention any VLAN ID information. Therefore, this option is false.

Option D: " The management IP address of the peer device is 192.168.1.1. " ✅ Correct

The Management address field in the LLDP output confirms the IP address as 192.168.1.1, making this statement true.

HCIP-Datacom-Advanced Routing & Switching Technology References:

Huawei HCIP-Datacom Official Certification Guide, Chapter on LLDP and Network Device Discovery.

HCIA/HCIP Datacom Training Materials – LLDP Neighbor Discovery Commands.

Huawei Datacom Configuration Guide – Section on display lldp neighbor interface.

A super-VLAN provides a shared Layer 3 gateway for its associated sub-VLANs, but the sub-VLANs remain separate broadcast domains. Because hosts in different sub-VLANs commonly use addresses from the same IP subnet, they initially attempt direct ARP resolution. The ARP broadcast cannot cross the sub-VLAN boundary. Enabling proxy ARP on the super-VLAN’s VLANIF interface allows the switch to respond and then route traffic between the sub-VLANs. Therefore, option D is correct.

The other options are incorrect:

A: The super-VLAN’s VLANIF interface becomes Up only when at least one physical interface in an associated sub-VLAN is Up—not merely any physical interface on the switch.

B: Huawei explicitly prohibits configuring VLAN 1 as a super-VLAN.

C: Different sub-VLANs are independent broadcast domains and cannot communicate directly at Layer 2. Their communication requires Layer 3 forwarding through the super-VLAN VLANIF interface, normally assisted by proxy ARP.

Huawei also specifies that a super-VLAN contains no physical interfaces; physical interfaces belong to its sub-VLANs. Huawei Super-VLAN overview, Huawei super-VLAN restrictions

BGP/MPLS IP VPN networks use Multiprotocol BGP (MP-BGP) to distribute VPNv4 routing information between Provider Edge (PE) routers.

An MP-BGP Update message carries the VPNv4 route prefix, next-hop information, VPN label, and extended community attributes, including the export Route Target (RT).

The VPNv4 prefix consists of a Route Distinguisher (RD) and an IPv4 prefix, allowing overlapping customer networks to be distinguished.

The next-hop address identifies the PE router associated with the advertised route. The RT determines which VPN instances are permitted to import the route.

However, the public network label is not distributed through the VPNv4 BGP Update message. It is normally assigned and distributed through the provider ' s MPLS label distribution mechanism, such as LDP.

Therefore, the correct answers are B, C, and D.

HCIP-Datacom-Advanced Routing & Switching Technology V1.0 Training Material.pdf

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