H12-821_V1.0 Exam Results

 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.

 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.

 HCIP-Datacom-Core Reference

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

Comprehensive and Detailed In-Depth Explanation:

In IS-IS, routes are distributed differently based on router levels:

Level-1 (L1) routers → Maintain specific routes only within their own area.

Level-2 (L2) routers → Maintain specific routes for the entire network (inter-area routing).

Level-1-2 (L1/L2) routers → Store both L1 and L2 routes and act as area border routers.

In the diagram, R2 and R3 are L1/L2 routers, meaning they store specific routes for both their area and other areas.

R1 is only an L1 router, meaning it only has intra-area routes, and R7 is an L2-only router, meaning it does not store all specific routes.

Therefore, R2 and R3 have specific routes for the entire network.

???? Reference: Huawei HCIA-Datacom Study Guide, IS-IS Routing Levels and Route Distribution.

Comprehensive and Detailed in-depth Step-by-Step Explanation:

In OSPF, Link State Advertisements (LSAs) are used to exchange routing and topology information. Each LSA in the OSPF network is uniquely identified using a 3-tuple identifier, which consists of:

Link State ID:

The Link State ID uniquely identifies the LSA within the OSPF area. Its value depends on the LSA type. For example, for a Router LSA, the Link State ID is the originating router’s Router ID.

Advertising Router:

This is the Router ID of the router that generated the LSA. It identifies which router is responsible for creating and advertising this LSA.

LSType:

This field identifies the type of LSA (e.g., Router LSA, Network LSA, Summary LSA, AS-External LSA, etc.). It is crucial for interpreting the purpose and content of the LSA.

The LS Sequence Number is not part of the 3-tuple that uniquely identifies the LSA. Instead, it is used to determine the most recent version of the LSA in case there are multiple instances of the same LSA.