Huawei H12-821_V1.0 - HCIP-Datacom-Core Technology V1.0

ï‚· IGMP:Manages IPv4 multicast group members and runs on the multicast network's last segment (that is, the network segment where a Layer 3 network device is connected to user hosts).

ï‚· PIM:Sends multicast data over the network to the multicast device that is connected to group members that have requested the multicast data, implementing multicast data forwarding based on routes.

ï‚· IGMP Snooping:Manages and controls the forwarding of multicast data packets to effectively suppress the flooding of multicast data packets on the Layer 2 network.

ï‚· IGMP (Internet Group Management Protocol):

IGMP is used by hosts and adjacent multicast routers to establish and maintain multicast group memberships on a local subnet.

It allows a host to inform a multicast router of its desire to receive multicast traffic for a specific group.

It operates at Layer 3 and runs on the last segment of the network.

HCIP-Datacom-Core Technology Training Material (Multicast Fundamentals)​.

ï‚· PIM (Protocol Independent Multicast):

PIM is a routing protocol designed for efficient routing of IP multicast traffic. It determines the paths over which multicast packets should be forwarded.

PIM is "protocol-independent" because it uses the underlying unicast routing table for RPF (Reverse Path Forwarding) checks.

It is responsible for distributing multicast data throughout the network.

Understanding the LSDB and Level-2 DIS Election in IS-IS:

In IS-IS, theDesignated Intermediate System (DIS)is elected for both Level-1 and Level-2 on broadcast networks to manage the link-state database (LSDB) and reduce the number of LSAs exchanged.

The election of the DIS is based on thehighest priority. If the priority is the same, the router with thehighest System IDbecomes the DIS.

HCIP-Datacom-Core Technology Training Material (IS-IS DIS Election)​​.

Analyzing the LSDB:

From the LSDB ofR1, the Level-2 link-state database includes the following entries:

LSPID 0100.0000.3003.00-00: This is R3, and it is present in the Level-2 LSDB with the sequence number and checksum details.

Other routers (R1, R2, R4) are present but do not have the characteristics of the Level-2 DIS in this topology.

Based on the System IDs,R3 (0100.0000.3003)has the highest System ID, making it theLevel-2 DIS.

Conclusion:

The Level-2 DIS on the network isR3, based on the election rules and the LSDB information shown in the figure.

ï‚· Transitive vs. Non-Transitive Attributes

The Community attribute is atransitive optional attribute, meaning that if a router receives a route with this attribute and does not understand its purpose, the router retains and propagates it to other peers.

Other options, such as AS_Path and MED, are well-defined mandatory or optional attributes with specific purposes.

ï‚· HCIP-Datacom-Core Reference

The behavior of optional transitive attributes is detailed in the BGP protocol and attribute chapters​​.

A is correct– Local attack defense can classify and prioritize packets (e.g., OSPF, BGP, SSH) andensure critical protocols are processed firstby the CPU.

B is correct– Thedynamic link protection functionensures session-based applications (like SSH)are not disruptedeven during a CPU attack.

C is false– Different protocols havedifferent importance levels, soindividual rate limitsshould be configured, not a uniform one.

D is correct– CPU protectionalso applies to management interfaces, such as those used for Telnet, SSH, or SNMP.

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“Devices support local attack defense by classifying packets, setting priorities, and limiting rates to protect CPU resources. These policies also apply to the management interface.”

(Chapter: Network Security – Section: Local Attack Defense)

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 ​.

If VRRP is not configured to track uplink interfaces, a failure in the master device's uplink or link will not trigger a switchover, resulting in a traffic blackhole. The VRRP mechanism relies on interface tracking to monitor connectivity and ensure role transitions upon faults. Without this configuration, no failover occurs, and traffic directed toward the master device is lost ​.

ATotally Stubby Areain OSPF is a special type of stub area where onlyintra-area (Type 1) LSAs,router LSAs, anddefault routes (Type 3 LSA with 0.0.0.0/0)are allowed to be injected. Itblocks inter-area routes (Type 3 LSAs for specific prefixes)andType 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 Areasdo 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

When STP and RSTP coexist in a network, RSTP switches will downgrade their operation to STP to ensure compatibility. However, this disables RSTP's rapid convergence features, as the protocol behaves like STP to maintain interoperability ​.

ï‚· pat

ï‚· trust

ï‚· 12.1.1.0

ï‚· inner