H12-821_V1.0 Exam Dumps - Huawei HCIP-Datacom Questions and Answers

All four are valid reasons why IKE (Internet Key Exchange) negotiation might not be triggered:

A – Security policy mismatches can block data flows , preventing IPsec from initiating.

B – If the route to the peer is unreachable , no packets can reach the tunnel interface, and IKE will not start.

C – If the IPsec policy is not bound to the correct interface , no protection is triggered.

D – If the ACL does not match the actual traffic , the flow will bypass IPsec.

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

“Common causes of IKE negotiation failure include incorrect ACLs, misapplied policies, unreachable peers, and misconfigured security zones.”

(Chapter: VPN Technologies – Section: IPsec Troubleshooting)

RSTP improves convergence by introducing changes to the BPDU handling mechanism and port roles. However, RSTP does not rely on a fixed timeout of four Hello intervals for negotiation failure. Instead, RSTP uses a more dynamic mechanism to detect topology changes. The other options describe valid RSTP improvements ​.

In OSPF (Open Shortest Path First), each router maintains a Link-State Database (LSDB) , which must be synchronized with other routers in the same area. When an OSPF router receives an LSA (Link-State Advertisement) that it does not already have in its LSDB , it takes the following steps:

It updates its LSDB with the new LSA.

It floods the LSA to all its other OSPF neighbors (except the one from which it received the LSA).

This ensures that all routers in the OSPF area eventually converge to the same network topology.

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

“When an LSA is received and it is newer or not present in the LSDB, the router updates the LSDB and floods the LSA to other neighbors to ensure database synchronization.”

(Chapter: OSPF Fundamentals – Section: LSDB Synchronization)

 ACL Number Ranges

Basic ACLs : Numbered from 2000 to 2999.

Advanced ACLs : Numbered from 3000 to 3999.

Layer 2 ACLs : Numbered from 5000 to 5999.

User-defined ACLs : Numbered from 4000 to 4999.

 HCIP-Datacom-Core Reference

ACL classifications and their number ranges are covered in the ACL principles and configuration chapters​​.

 IS-IS Overview : Intermediate System to Intermediate System (IS-IS) is a link-state routing protocol. Routers exchange Link State Packets (LSPs) to maintain a synchronized link-state database. These LSPs are categorized into Level-1 LSPs (intra-area routing) and Level-2 LSPs (inter-area routing). Both types share the same packet format.

By default, Huawei firewalls create security zones named untrust , dmz , trust , and local . These zones facilitate security policies for inbound, outbound, and inter-zone traffic control ​.

Comprehensive and Detailed Step-by-Step Explanation:

IS-IS Area Division:

IS-IS divides areas by routers , not by links. A router is assigned to a specific IS-IS area, but it can belong to multiple levels:

Level 1: Maintains the LSDB (Link State Database) for the local area only.

Level 2: Maintains the LSDB for the backbone area and exchanges routes between areas.

Behavior of a Level 1-2 Router:

A router configured as Level 1-2 must maintain two separate LSDBs:

One for intra-area routes (Level 1).

One for inter-area routes (Level 2).

Incorrect Statement:

The statement that an IS-IS router only needs to maintain the LSDB of its area is incorrect because Level 1-2 routers maintain LSDBs for both levels.

Comprehensive and Detailed Step-by-Step Explanation:

ACL Capabilities:

ACLs are versatile tools that can match:

Data packets: Using IP addresses, protocols, ports, etc.

Routes: ACLs can be used in route filtering, matching both IP prefix length and mask length.

Correct Statement:

ACLs can match both the IP address prefix length and mask length in route filtering applications.