Updated Huawei H12-821_V1.0 Practice Questions BY Strickland

Understanding DIS Election in IS-IS:

On an IS-IS broadcast network, a Designated Intermediate System (DIS) is elected to create and update pseudonodes for efficient communication.

The election is based on the following criteria:

DIS Priority: The router with the highest priority is elected as the DIS.

Router ID (tie-breaker): If priorities are equal, the router with the highest Router ID is elected.

Analyzing the DIS Priorities and Router IDs:

R1: Priority = 64, Router ID = 1.1.1.1

R2: Priority = 1, Router ID = 2.2.2.2

R3: Priority = 127, Router ID = 3.3.3.3

R4: Priority = 10, Router ID = 4.4.4.4

Among the routers, R3 has the highest DIS priority (127), making it the DIS.

Correct Option:

Option B (R3): Correct, as R3 has the highest priority.

Option A (R1): Incorrect, as its priority is lower (64).

Option C (R4): Incorrect, as its priority is lower (10).

Option D (R2): Incorrect, as its priority is the lowest (1).

HCIA-Datacom Study Guide, Chapter: IS-IS DIS Election

Huawei IS-IS Configuration and DIS Role Details

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)