Huawei Updated H12-821_V1.0 Exam Questions and Answers by faye

IPv4 supports three main transmission modes:

Unicast: One-to-one communication.

Broadcast: One-to-all communication within a network.

Multicast: One-to-many communication to a group of interested receivers.Anycast is not a native IPv4 mode but is introduced in IPv6 ​.

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 a3-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.

TheLS Sequence Numberis 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.

Comprehensive and Detailed In-Depth Explanation:

TheFlag fieldin a routing table entry provides specific information about the route.

G (Gateway flag): This flag indicates that the next hop is agateway (another router)rather than a directly connected destination.

S (Static flag): This flag indicates that the route was manually configured as astatic route.

H (Host flag): This flag means that the destination is adirectly connected host, not a network.

D (Dynamic flag): This flag is used fordynamically learned routesfrom protocols like OSPF, EIGRP, or BGP.

Since we are looking for the flag that indicates thenext hop is a gateway, the correct answer isG.

????Reference:Huawei HCIA-Datacom Study Guide, Chapter on Routing Table and FIB Entries.

In a route-policy, attributes such asMED(Multi-Exit Discriminator) andLocal-Preferencecan be used in apply clauses to influence BGP route selection. Attributes likeAS_PathandTagare typically matched or filtered but not directly applied in the apply clause ​.