H12-821_V1.0 Exam Dumps - HCIP-Datacom-Core Technology V1.0

The question indicates that a router performs a lookup in its FIB table for a packet and determines that the tunnel ID in the matching entry is 0, suggesting that the packet needs to be forwarded through a tunnel such as an MPLS tunnel. However, this is a misunderstanding of the FIB functionality.

FIB Table Overview The Forwarding Information Base (FIB) is used to make packet-forwarding decisions. Entries in the FIB include next-hop information, which can be directly linked to an interface or a tunnel.

If the Tunnel ID is 0 , it indicates that the packet is forwarded via a normal routing path and not through a tunnel.

For MPLS or other tunnels, the Tunnel ID would have a non-zero value pointing to the associated tunnel.

MPLS Tunnel Operation When a router forwards packets through an MPLS tunnel, a label-switched path (LSP) is set up. The FIB would reflect specific tunnel identifiers for packets that need such encapsulation.

HCIP-Datacom-Core Reference

Routing Principles and MPLS ​explain the forwarding mechanisms clearly, stating that if a packet is routed normally, the tunnel ID remains 0 .

The section on MPLS​clarifies the encapsulation process and the role of tunnel identifiers.

Hence, the claim in the question is incorrect. A Tunnel ID of 0 implies no tunneling is required, and normal IP forwarding occurs

In Huawei firewalls, the security level of a zone can be reconfigured by an administrator, making the statement that it cannot be changed false. Other statements accurately describe security level restrictions or defaults ​.

Comprehensive and Detailed Step-by-Step Explanation:

1. Understanding the Prefix List Configuration:

The command ip ip-prefix test index 10 permit 10.0.0.0 8 less-equal 32 defines the following:

The prefix base is 10.0.0.0 with a mask length of 8 bits.

The less-equal 32 condition allows routes with mask lengths ranging from 8 to 32 bits to match.

2. Analysis of Each Route:

Option A: 10.1.1.1/32

Correct .

The prefix 10.1.1.1/32 falls within the 10.0.0.0/8 network range and has a mask length of 32 bits, which satisfies the less-equal 32 condition.

Option B: 10.1.1.0/6

Incorrect .

The prefix 10.1.1.0/6 has a mask length of 6 bits, which is shorter than the base prefix length of 8. It does not satisfy the condition.

Option C: 10.1.1.0/24

Correct .

The prefix 10.1.1.0/24 falls within the 10.0.0.0/8 network range and has a mask length of 24 bits, which satisfies the less-equal 32 condition.

Option D: 10.0.0.0/16

Correct .

The prefix 10.0.0.0/16 falls within the 10.0.0.0/8 network range and has a mask length of 16 bits, which satisfies the less-equal 32 condition.

3. Summary:

The prefixes that match the configuration are 10.1.1.1/32, 10.1.1.0/24, and 10.0.0.0/16.

When a Huawei firewall receives a packet that does not match any existing session table entry, it discards the packet. This is part of the default firewall policy, which ensures that unrecognized traffic is treated as a potential security risk and blocked. This behavior is vital for preventing unauthorized access and mitigating external attacks. The feature aligns with Huawei ' s default security strategies as detailed in their firewall operation manuals ​.

ï‚· Export Routing Policy Changes

When an export routing policy is modified, BGP does not automatically resend affected routes. Manual intervention, such as a clear ip bgp command, is required to resend Update messages reflecting the new policy.

ï‚· Incorrect Options

B. IGP routes can also be advertised into BGP using redistribution, not just the network command.

C. A router can be configured with multiple BGP processes using different AS numbers (multi-instance BGP).

D. Open messages carry additional parameters such as AS number, Hold Time, and Router ID, not just the header.

ï‚· HCIP-Datacom-Core Reference

BGP policy and update behavior are detailed in the route control and redistribution chapters​​.

Comprehensive and Detailed Step-by-Step Explanation:

1. What is GRE (Generic Routing Encapsulation)?

GRE is a tunneling protocol that allows the encapsulation of various types of packets (e.g., IPv4, IPv6, multicast, etc.) to be transmitted over another protocol (e.g., IP).

GRE is used to create point-to-point connections over heterogeneous networks.

2. Analysis of Each Option:

Option A: GRE is a Layer 2 VPN encapsulation technology.

Incorrect.

GRE operates at Layer 3 (Network Layer) and encapsulates Layer 3 packets. It is not a Layer 2 VPN encapsulation technology like MPLS or Ethernet-over-IP.

Option B: GRE enables encapsulated data packets to be transmitted over another network layer protocol, but cannot encapsulate multicast data.

Incorrect.

GRE supports the encapsulation and transmission of multicast data packets. This is one of its key features, making it suitable for protocols like OSPF and multicast applications.

Option C: GRE tunnels can work with IPsec to ensure the security of multicast services such as voice and video.

Correct.

GRE by itself does not provide encryption or security. However, GRE can work with IPsec to secure the encapsulated traffic, including multicast data, for services like voice and video.

Option D: GRE tunnels can extend the working range of network protocols with hop limits.

Correct.

GRE encapsulates packets, effectively resetting their hop limits and allowing protocols with limited hop counts (e.g., RIP) to work over larger networks.

3. Summary:

The correct options are C and D .

A Totally Stubby Area in OSPF is a special type of stub area where only intra-area (Type 1) LSAs , router LSAs , and default routes (Type 3 LSA with 0.0.0.0/0) are allowed to be injected. It blocks inter-area routes (Type 3 LSAs for specific prefixes) and Type 5 LSAs (external routes) to reduce the size of the Link-State Database (LSDB) and enhance router performance.

Explanation of the Options:

A. Type 3 specific LSA – ❌ Correct Answer . These LSAs represent inter-area routes. Totally Stubby Areas do not allow Type 3 LSAs for specific routes , only for the default route (0.0.0.0/0).

B. Type 1 LSA – ✅ Allowed. These are Router LSAs generated by routers within the area and are necessary for OSPF to function.

C. Type 3 LSA that describes a default route – ✅ Allowed. This is the only Type 3 LSA permitted in a Totally Stubby Area. It provides a default route (0.0.0.0/0) to reach external destinations.

D. Type 2 LSA – ✅ Allowed if there are broadcast or NBMA networks in the area. These describe the network segment in multi-access environments and are generated by the DR.

Official Huawei Reference:

📘 Huawei HCIP-Datacom-Core Technology Study Guide –

Chapter: OSPF Special Areas

" A totally stub area does not allow inter-area Type 3 LSAs or external Type 5 LSAs to enter. Only a default route is injected in the form of a Type 3 LSA (0.0.0.0/0), which greatly reduces the LSDB size. "

📚 Also refer to:

Huawei VRP Command Guide > OSPF > Configuration Notes > OSPF Special Areas